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PIEWriter dot codes are case-insensitive, and I've deciphered that .pp is a
paragraph break.  Replace those with blank lines.  The NUL at EOF was escaped,
but it can be simply deleted.  Did so.
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13
D1S1/CH1#064000.txt
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@ -12,7 +12,7 @@
.ce .ce
CHAPTER 1 - INTRODUCTION CHAPTER 1 - INTRODUCTION
.sp 2 .sp 2
.pp
Beneath Apple DOS is intended Beneath Apple DOS is intended
to serve as a companion to Apple's to serve as a companion to Apple's
DOS Manual, providing additional DOS Manual, providing additional
@ -35,7 +35,7 @@ contents of the DOS Manual. Since
all chapters presented here may not all chapters presented here may not
be of use to each Apple owner, each be of use to each Apple owner, each
has been written to stand on its own. has been written to stand on its own.
.pp
The information presented here is a The information presented here is a
result of intensive disassembly and result of intensive disassembly and
annotation of various versions of DOS annotation of various versions of DOS
@ -53,7 +53,7 @@ presented here, all of the material
included in Beneath Apple DOS has included in Beneath Apple DOS has
been thoroughly researched and been thoroughly researched and
tested. tested.
.pp
There were several reasons There were several reasons
for writing Beneath Apple DOS: for writing Beneath Apple DOS:
.SP1 .SP1
@ -68,7 +68,7 @@ To allow you to customize DOS to fit your needs.
.br .br
To provide complete information on diskette formatting. To provide complete information on diskette formatting.
.br .br
.pp
When Apple Computer Inc. introduced When Apple Computer Inc. introduced
its Disk Operating System (DOS) its Disk Operating System (DOS)
version 3 in 1978 to support the version 3 in 1978 to support the
@ -95,7 +95,7 @@ where the
Disk Operating System Disk Operating System
Manual leaves off. Manual leaves off.
.bp .bp
.pp
Throughout this manual, discussion Throughout this manual, discussion
centers primarily on DOS version centers primarily on DOS version
3.3. The reasons for this are that 3.3 3.3. The reasons for this are that 3.3
@ -106,7 +106,7 @@ would imagine. Wherever there is a
major difference between the various major difference between the various
DOS releases in a given topic, each DOS releases in a given topic, each
release will be covered. release will be covered.
.pp
In addition to the DOS dependent In addition to the DOS dependent
information provided, many of the information provided, many of the
discussions also apply to discussions also apply to
@ -117,4 +117,3 @@ the track and sector level is, for
the most part, the same. the most part, the same.
.br .br
.nx ch2 .nx ch2
\x00

57
D1S1/CH2#064000.txt
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@ -3,7 +3,7 @@
.ce .ce
CHAPTER 2 - THE EVOLUTION OF DOS CHAPTER 2 - THE EVOLUTION OF DOS
.sp 2 .sp 2
.pp
Since its introduction, Apple DOS has Since its introduction, Apple DOS has
gone through three major versions. gone through three major versions.
All of these versions look All of these versions look
@ -22,7 +22,7 @@ fit on a track from 13 to 16.
DOS 3 - 29 June 1978 DOS 3 - 29 June 1978
.br .br
DOS 3.1 - 20 July 1978 DOS 3.1 - 20 July 1978
.pp
The first release of DOS was The first release of DOS was
apparently a victim of a rush at apparently a victim of a rush at
Apple to introduce the DISK II. As Apple to introduce the DISK II. As
@ -32,7 +32,7 @@ and the introduction of the AUTOSTART
ROM, a new release was needed. ROM, a new release was needed.
.SP1 .SP1
DOS 3.2 - 16 February 1979 DOS 3.2 - 16 February 1979
.pp
Although DOS 3.2 embodied more Although DOS 3.2 embodied more
changes from its changes from its
predecessor than any other release of predecessor than any other release of
@ -44,37 +44,37 @@ are listed below:
.pi-2 .pi-2
.in2 .in2
.ps0 .ps0
.pp
- NOMON C,I,O is the initial default - NOMON C,I,O is the initial default
under DOS 3.2. MON C,I,O was the under DOS 3.2. MON C,I,O was the
default under DOS 3.1. default under DOS 3.1.
.pp
- Input prompts (>,],*) are echoed - Input prompts (>,],*) are echoed
when MON O is in effect, not under when MON O is in effect, not under
MON I as was the case under 3.1. MON I as was the case under 3.1.
.pp
- When a DOS command was entered from - When a DOS command was entered from
the keyboard, DOS executed it and the keyboard, DOS executed it and
then passed a blank followed by a then passed a blank followed by a
carriage return to BASIC under 3.1. Under 3.2 carriage return to BASIC under 3.1. Under 3.2
only a carriage return is passed. only a carriage return is passed.
.pp
- Under 3.2, certain commands may not - Under 3.2, certain commands may not
be entered from the keyboard but may be entered from the keyboard but may
only be used within a BASIC program only be used within a BASIC program
(READ, WRITE, POSITION, OPEN, (READ, WRITE, POSITION, OPEN,
APPEND). APPEND).
.pp
- Under 3.2, when LOADing an APPLESOFT program, - Under 3.2, when LOADing an APPLESOFT program,
DOS automatically DOS automatically
converts from APPLESOFT ROM format to converts from APPLESOFT ROM format to
APPLESOFT RAM format if the RAM version of APPLESOFT RAM format if the RAM version of
BASIC is in use and vice versa. BASIC is in use and vice versa.
.pp
- DOS 3.1 could not read lower case - DOS 3.1 could not read lower case
characters from a text file; DOS 3.2 characters from a text file; DOS 3.2
can. can.
.pp
.bp .bp
- Some DOS commands are allowed to - Some DOS commands are allowed to
create a new file, others will not. create a new file, others will not.
@ -88,30 +88,30 @@ XYZ, and then printed the file not
found error message.) Under 3.2, OPEN found error message.) Under 3.2, OPEN
is allowed to create a file if one is allowed to create a file if one
does not exist, but LOAD may not. does not exist, but LOAD may not.
.pp
- Under 3.1, exiting to the monitor - Under 3.1, exiting to the monitor
required that the monitor status required that the monitor status
register location ($48) be set to register location ($48) be set to
zero before reentering DOS. Under DOS zero before reentering DOS. Under DOS
3.2 this is no longer necessary. 3.2 this is no longer necessary.
.pp
- The Read/Write-Track/Sector (RWTS) - The Read/Write-Track/Sector (RWTS)
section of DOS disables interrupts section of DOS disables interrupts
while it is executing. Under 3.1, while it is executing. Under 3.1,
RWTS could be interrupted by a RWTS could be interrupted by a
peripheral while writing to a disk, peripheral while writing to a disk,
destroying the disk. destroying the disk.
.pp
- The default for the B (byte offset) keyword is 0 - The default for the B (byte offset) keyword is 0
under 3.2. under 3.2.
.pp
- DOS was reassembled for 3.2 causing most of - DOS was reassembled for 3.2 causing most of
its interesting locations and its interesting locations and
routines to move slightly. This routines to move slightly. This
played havoc with user programs and played havoc with user programs and
utilities which had DOS addresses utilities which had DOS addresses
built into them. built into them.
.pp
- Additional file types (beyond - Additional file types (beyond
T, I, A, and B) are defined within T, I, A, and B) are defined within
DOS 3.2, although no commands yet DOS 3.2, although no commands yet
@ -122,14 +122,14 @@ DOS TOOLKIT for relocatable object
module assembler files. At present, module assembler files. At present,
no other use is made of these no other use is made of these
extra file types. extra file types.
.pp
- Support was added under 3.2 for the - Support was added under 3.2 for the
AUTOSTART ROM. AUTOSTART ROM.
.pp
- All files open when a disk full - All files open when a disk full
condition occurs are closed by DOS condition occurs are closed by DOS
3.2. 3.2.
.pp
- As with each new release of DOS, - As with each new release of DOS,
several new programs were added to several new programs were added to
the master diskette for 3.2. Among the master diskette for 3.2. Among
@ -145,7 +145,7 @@ renamed.
.ps1 .ps1
.sp1 .sp1
DOS 3.2.1 - 31 July 1979 DOS 3.2.1 - 31 July 1979
.PP
DOS 3.2.1 was essentially a DOS 3.2.1 was essentially a
"maintenance release" of DOS 3.2. "maintenance release" of DOS 3.2.
Minor patches were made to RWTS and Minor patches were made to RWTS and
@ -155,7 +155,7 @@ done. Additional delays were added
following a switch between drives. following a switch between drives.
.bp .bp
DOS 3.3 - 25 August 1980 DOS 3.3 - 25 August 1980
.PP
Introduced in mid 1980 as a Introduced in mid 1980 as a
hardware/software upgrade from DOS hardware/software upgrade from DOS
3.2.1, the DOS 3.3 package includes 3.2.1, the DOS 3.3 package includes
@ -183,7 +183,7 @@ received a few patches:
.pi-2 .pi-2
.in2 .in2
.ps0 .ps0
.pp
- The initial DOS bootstrap loader - The initial DOS bootstrap loader
was moved to $800 under 3.3. It was was moved to $800 under 3.3. It was
at $300 under 3.2. In addition, as at $300 under 3.2. In addition, as
@ -191,16 +191,16 @@ stored on the diskette (track 0
sector 0) it is nibbilized in the sector 0) it is nibbilized in the
same way as all other sectors under same way as all other sectors under
3.3. 3.3.
.pp
- A bug in APPEND which caused it to - A bug in APPEND which caused it to
position improperly if the file was a position improperly if the file was a
multiple of 256 bytes long was fixed multiple of 256 bytes long was fixed
under 3.3. under 3.3.
.pp
- A VERIFY command is internally - A VERIFY command is internally
executed after every SAVE or BSAVE executed after every SAVE or BSAVE
under 3.3. under 3.3.
.pp
- All 4 bytes are used in the Volume - All 4 bytes are used in the Volume
Table Of Contents (VTOC) free sector bit map when Table Of Contents (VTOC) free sector bit map when
keeping track of free sectors. This keeping track of free sectors. This
@ -208,20 +208,20 @@ allows DOS to handle up to 32 sectors
per track. Of course, RWTS will only per track. Of course, RWTS will only
handle 16 sectors due to hardware handle 16 sectors due to hardware
limitations. limitations.
.pp
- If a LANGUAGE CARD is present, DOS - If a LANGUAGE CARD is present, DOS
stores a zero on it at $E000 during stores a zero on it at $E000 during
bootstrap to force the HELLO program bootstrap to force the HELLO program
on the master diskette to reload on the master diskette to reload
BASIC. BASIC.
.pp
- DOS is read into memory from the - DOS is read into memory from the
top down (backwards) under 3.3 rather than the top down (backwards) under 3.3 rather than the
bottom up. Its image is bottom up. Its image is
still stored in the same order on the still stored in the same order on the
diskette (tracks 0, 1, and 2), diskette (tracks 0, 1, and 2),
however. however.
.pp
- Additional programs added to the - Additional programs added to the
master diskette under 3.3 include master diskette under 3.3 include
FID, a generalized file utility which FID, a generalized file utility which
@ -234,7 +234,7 @@ will boot a 13 sector diskette,
and a new COPY program and a new COPY program
which will also support single drive which will also support single drive
copies. copies.
.pp
- Under 3.2, speed differences in - Under 3.2, speed differences in
some drives prevented their use some drives prevented their use
together with the DOS COPY program. together with the DOS COPY program.
@ -246,4 +246,3 @@ applies.
.in0 .in0
.ps1 .ps1
.nx ch3.1 .nx ch3.1
\x00

51
D1S1/CH3.1#064000.txt
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@ -3,7 +3,7 @@
.ce .ce
CHAPTER 3 - DISK II HARDWARE AND TRACK FORMATTING CHAPTER 3 - DISK II HARDWARE AND TRACK FORMATTING
.sp 2 .sp 2
.pp
Apple Computer's excellent manual on Apple Computer's excellent manual on
the Disk Operating System (DOS) the Disk Operating System (DOS)
provides only very basic information provides only very basic information
@ -14,7 +14,7 @@ diskette. The first section will
contain a brief introduction to the contain a brief introduction to the
hardware, and may be skipped by those hardware, and may be skipped by those
already familiar with the DOS manual. already familiar with the DOS manual.
.pp
For system housekeeping, DOS divides For system housekeeping, DOS divides
diskettes into tracks and sectors. diskettes into tracks and sectors.
This is done during the This is done during the
@ -43,7 +43,7 @@ tracks, although they are invisible
to the eye on a real diskette. to the eye on a real diskette.
.sp1 .sp1
*** INSERT FIGURE 3.1 HERE *** *** INSERT FIGURE 3.1 HERE ***
.pp
It should be pointed out, for the It should be pointed out, for the
sake of accuracy, that the disk arm sake of accuracy, that the disk arm
can position itself over 70 "phases". can position itself over 70 "phases".
@ -67,7 +67,7 @@ two phases from one another. See
APPENDIX B for more information on APPENDIX B for more information on
protection schemes. protection schemes.
.bp .bp
.pp
A sector is a subdivision of a track. A sector is a subdivision of a track.
It is the smallest unit of It is the smallest unit of
"updatable" data on the diskette. "updatable" data on the diskette.
@ -130,14 +130,14 @@ USABLE* BYTES PER DISKETTE
* Excludes DOS, VTOC, and CATALOG * Excludes DOS, VTOC, and CATALOG
.bp .bp
TRACK FORMATTING TRACK FORMATTING
.pp
Up to this point we have broken down Up to this point we have broken down
the structure of data to the track the structure of data to the track
and sector level. To better and sector level. To better
understand how understand how
data is stored and retrieved, we will data is stored and retrieved, we will
start at the bottom and work up. start at the bottom and work up.
.pp
As this manual is primarily concerned As this manual is primarily concerned
with software, no attempt will be with software, no attempt will be
made to deal with the specifics of made to deal with the specifics of
@ -150,7 +150,7 @@ hardware converts analog data to
digital data but how this is digital data but how this is
accomplished is beyond the scope of accomplished is beyond the scope of
this manual. this manual.
.pp
Data is recorded on the diskette Data is recorded on the diskette
using frequency modulation as the using frequency modulation as the
recording mode. Each data bit recording mode. Each data bit
@ -163,7 +163,7 @@ pattern shown represents a binary
value of 101. value of 101.
.sp1 .sp1
*** INSERT FIGURE 3.2 HERE *** *** INSERT FIGURE 3.2 HERE ***
.pp
As can be seen in Figure 3.3, the As can be seen in Figure 3.3, the
clock bits and data bits (if present) clock bits and data bits (if present)
are interleaved. The presence of a are interleaved. The presence of a
@ -177,7 +177,7 @@ bit and the leading edge of the next
clock bit. clock bit.
.sp1 .sp1
*** INSERT FIGURE 3.3 HERE *** *** INSERT FIGURE 3.3 HERE ***
.PP
A byte would consist of eight (8) A byte would consist of eight (8)
consecutive bit cells. The most consecutive bit cells. The most
significant bit cell is usually significant bit cell is usually
@ -200,7 +200,7 @@ illustrates the relationship of the
bits within a byte. bits within a byte.
.bp .bp
*** INSERT FIGURE 3.4 HERE *** *** INSERT FIGURE 3.4 HERE ***
.PP
To graphically show how bits are To graphically show how bits are
stored and retrieved, we must take stored and retrieved, we must take
certain liberties. The diagrams are certain liberties. The diagrams are
@ -218,7 +218,7 @@ embodies the function of data flow to
and from the diskette. and from the diskette.
.sp1 .sp1
*** INSERT FIGURE 3.5 HERE *** *** INSERT FIGURE 3.5 HERE ***
.pp
Figure 3.5 shows the three bits, 101, Figure 3.5 shows the three bits, 101,
being read from the diskette data being read from the diskette data
stream into the data latch. Of stream into the data latch. Of
@ -229,7 +229,7 @@ clock bits. This task is done by the
hardware and is shown more for hardware and is shown more for
accuracy than for its importance to accuracy than for its importance to
our discussion. our discussion.
.pp
Writing data can be depicted in much Writing data can be depicted in much
the same way (see Figure 3.6). the same way (see Figure 3.6).
The clock bits which The clock bits which
@ -250,7 +250,7 @@ Self-sync bytes will be covered in
detail shortly. detail shortly.
.sp1 .sp1
*** INSERT FIGURE 3.6 HERE *** *** INSERT FIGURE 3.6 HERE ***
.PP
A "field" is made up of a group of A "field" is made up of a group of
consecutive consecutive
bytes. The number of bytes varies, bytes. The number of bytes varies,
@ -273,7 +273,7 @@ computer time
to decode the address field before to decode the address field before
the corresponding data field can pass the corresponding data field can pass
beneath the read/write head. beneath the read/write head.
.pp
All gaps are primarily alike in All gaps are primarily alike in
content, consisting of self-sync content, consisting of self-sync
hexadecimal FF's, and vary only in hexadecimal FF's, and vary only in
@ -283,7 +283,7 @@ of a typical track, broken into its
major components. major components.
.bp .bp
*** INSERT FIGURE 3.7 HERE *** *** INSERT FIGURE 3.7 HERE ***
.PP
Self-sync or auto-sync bytes are Self-sync or auto-sync bytes are
special bytes that make up the three special bytes that make up the three
different types of gaps on a track. different types of gaps on a track.
@ -325,14 +325,14 @@ have been stripped out and 0's and
1's have been used for clarity. 1's have been used for clarity.
.sp1 .sp1
*** INSERT FIGURE 3.8 HERE *** *** INSERT FIGURE 3.8 HERE ***
.pp
There is no way from looking at the There is no way from looking at the
data to tell what bytes are data to tell what bytes are
represented, because we don't know represented, because we don't know
where to start. This is exactly the where to start. This is exactly the
problem that self-sync bytes problem that self-sync bytes
overcome. overcome.
.pp
A self-sync byte is defined to be a A self-sync byte is defined to be a
hexadecimal FF with a special hexadecimal FF with a special
difference. It is, in fact, a 10 bit difference. It is, in fact, a 10 bit
@ -344,7 +344,7 @@ elsewhere on the disk and a self-sync
hex FF byte. hex FF byte.
.bp .bp
*** INSERT FIGURE 3.9 HERE *** *** INSERT FIGURE 3.9 HERE ***
.pp
A self-sync is generated by using a A self-sync is generated by using a
40 cycle (micro-second) loop while 40 cycle (micro-second) loop while
writing an FF. A bit is written writing an FF. A bit is written
@ -378,7 +378,7 @@ the data unless there is an error on
the track. the track.
.sp1 .sp1
*** INSERT FIGURE 3.10 *** *** INSERT FIGURE 3.10 ***
.PP
We can now discuss the particular We can now discuss the particular
portions of a track in detail. The portions of a track in detail. The
three gaps will be covered first. three gaps will be covered first.
@ -395,7 +395,7 @@ bytes must be maintained for
each gap type (as discussed earlier). each gap type (as discussed earlier).
The result is fairly uniform gap The result is fairly uniform gap
sizes within each particular track. sizes within each particular track.
.pp
Gap 1 is the first data written to a Gap 1 is the first data written to a
track during initialization. Its track during initialization. Its
purpose is twofold. The gap purpose is twofold. The gap
@ -422,7 +422,7 @@ as a Gap 3 type for Address Field
number 0 (See Figure 3.7 for number 0 (See Figure 3.7 for
clarity). clarity).
.bp .bp
.pp
Gap 2 appears after each Address Gap 2 appears after each Address
Field and before each Data Field. Field and before each Data Field.
Its length varies from five to ten bytes Its length varies from five to ten bytes
@ -474,7 +474,7 @@ byte. Figure 3.12 illustrates this.
*** INSERT FIGURE 3.11 HERE *** *** INSERT FIGURE 3.11 HERE ***
.SP1 .SP1
*** INSERT FIGURE 3.12 HERE *** *** INSERT FIGURE 3.12 HERE ***
.PP
Gap 3 appears after each Gap 3 appears after each
Data Field and before each Address Data Field and before each Address
Field. It is longer than Gap 2 and Field. It is longer than Gap 2 and
@ -498,7 +498,7 @@ the first part of the gap can be
overwritten or damaged. (See Figure overwritten or damaged. (See Figure
3.11 for clarity) 3.11 for clarity)
.bp .bp
.pp
An examination of the contents of the An examination of the contents of the
two types of fields is in order. two types of fields is in order.
The Address Field contains The Address Field contains
@ -516,7 +516,7 @@ detailed illustration is given in
Figure 3.13. Figure 3.13.
.sp1 .sp1
*** INSERT FIGURE 3.13 HERE *** *** INSERT FIGURE 3.13 HERE ***
.PP
The prologue consists of three bytes The prologue consists of three bytes
which form a unique sequence, found which form a unique sequence, found
in no other component of the track. in no other component of the track.
@ -552,7 +552,7 @@ that the drive is still in sync with
the bytes on the disk. These bytes the bytes on the disk. These bytes
are probably unnecessary, but do are probably unnecessary, but do
provide a means of double checking. provide a means of double checking.
.pp
The other field type is the Data The other field type is the Data
Field. Much like the Address Field, Field. Much like the Address Field,
it consists of a prologue, data, it consists of a prologue, data,
@ -575,4 +575,3 @@ in the Address Field and it serves
the same function. the same function.
.bp .bp
.nx ch3.2 .nx ch3.2
\x00

50
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@ -3,7 +3,7 @@
.ce .ce
CHAPTER 3 - DISK II HARDWARE AND TRACK FORMATTING CHAPTER 3 - DISK II HARDWARE AND TRACK FORMATTING
.sp 2 .sp 2
.pp
Apple Computer's excellent manual on Apple Computer's excellent manual on
the Disk Operating System (DOS) the Disk Operating System (DOS)
provides only very basic information provides only very basic information
@ -14,7 +14,7 @@ diskette. The first section will
contain a brief introduction to the contain a brief introduction to the
hardware, and may be skipped by those hardware, and may be skipped by those
already familiar with the DOS manual. already familiar with the DOS manual.
.pp
For system housekeeping, DOS divides For system housekeeping, DOS divides
diskettes into tracks and sectors. diskettes into tracks and sectors.
This is done during the This is done during the
@ -43,7 +43,7 @@ tracks, although they are invisible
to the eye on a real diskette. to the eye on a real diskette.
.sp1 .sp1
*** INSERT FIGURE 3.1 HERE *** *** INSERT FIGURE 3.1 HERE ***
.pp
It should be pointed out, for the It should be pointed out, for the
sake of accuracy, that the disk arm sake of accuracy, that the disk arm
can position itself over 70 "phases". can position itself over 70 "phases".
@ -67,7 +67,7 @@ two phases from one another. See
APPENDIX B for more information on APPENDIX B for more information on
protection schemes. protection schemes.
.bp .bp
.pp
A sector is a subdivision of a track. A sector is a subdivision of a track.
It is the smallest unit of It is the smallest unit of
"updatable" data on the diskette. "updatable" data on the diskette.
@ -130,14 +130,14 @@ USABLE* BYTES PER DISKETTE
* Excludes DOS, VTOC, and CATALOG * Excludes DOS, VTOC, and CATALOG
.bp .bp
TRACK FORMATTING TRACK FORMATTING
.pp
Up to this point we have broken down Up to this point we have broken down
the structure of data to the track the structure of data to the track
and sector level. To better and sector level. To better
understand how understand how
data is stored and retrieved, we will data is stored and retrieved, we will
start at the bottom and work up. start at the bottom and work up.
.pp
As this manual is primarily concerned As this manual is primarily concerned
with software, no attempt will be with software, no attempt will be
made to deal with the specifics of made to deal with the specifics of
@ -150,7 +150,7 @@ hardware converts analog data to
digital data but how this is digital data but how this is
accomplished is beyond the scope of accomplished is beyond the scope of
this manual. this manual.
.pp
Data is recorded on the diskette Data is recorded on the diskette
using frequency modulation as the using frequency modulation as the
recording mode. Each data bit recording mode. Each data bit
@ -163,7 +163,7 @@ pattern shown represents a binary
value of 101. value of 101.
.sp1 .sp1
*** INSERT FIGURE 3.2 HERE *** *** INSERT FIGURE 3.2 HERE ***
.pp
As can be seen in Figure 3.3, the As can be seen in Figure 3.3, the
clock bits and data bits (if present) clock bits and data bits (if present)
are interleaved. The presence of a are interleaved. The presence of a
@ -177,7 +177,7 @@ bit and the leading edge of the next
clock bit. clock bit.
.sp1 .sp1
*** INSERT FIGURE 3.3 HERE *** *** INSERT FIGURE 3.3 HERE ***
.PP
A byte would consist of eight (8) A byte would consist of eight (8)
consecutive bit cells. The most consecutive bit cells. The most
significant bit cell is usually significant bit cell is usually
@ -200,7 +200,7 @@ illustrates the relationship of the
bits within a byte. bits within a byte.
.bp .bp
*** INSERT FIGURE 3.4 HERE *** *** INSERT FIGURE 3.4 HERE ***
.PP
To graphically show how bits are To graphically show how bits are
stored and retrieved, we must take stored and retrieved, we must take
certain liberties. The diagrams are certain liberties. The diagrams are
@ -218,7 +218,7 @@ embodies the function of data flow to
and from the diskette. and from the diskette.
.sp1 .sp1
*** INSERT FIGURE 3.5 HERE *** *** INSERT FIGURE 3.5 HERE ***
.pp
Figure 3.5 shows the three bits, 101, Figure 3.5 shows the three bits, 101,
being read from the diskette data being read from the diskette data
stream into the data latch. Of stream into the data latch. Of
@ -229,7 +229,7 @@ clock bits. This task is done by the
hardware and is shown more for hardware and is shown more for
accuracy than for its importance to accuracy than for its importance to
our discussion. our discussion.
.pp
Writing data can be depicted in much Writing data can be depicted in much
the same way (see Figure 3.6). the same way (see Figure 3.6).
The clock bits which The clock bits which
@ -250,7 +250,7 @@ Self-sync bytes will be covered in
detail shortly. detail shortly.
.sp1 .sp1
*** INSERT FIGURE 3.6 HERE *** *** INSERT FIGURE 3.6 HERE ***
.PP
A "field" is made up of a group of A "field" is made up of a group of
consecutive consecutive
bytes. The number of bytes varies, bytes. The number of bytes varies,
@ -273,7 +273,7 @@ computer time
to decode the address field before to decode the address field before
the corresponding data field can pass the corresponding data field can pass
beneath the read/write head. beneath the read/write head.
.pp
All gaps are primarily alike in All gaps are primarily alike in
content, consisting of self-sync content, consisting of self-sync
hexadecimal FF's, and vary only in hexadecimal FF's, and vary only in
@ -283,7 +283,7 @@ of a typical track, broken into its
major components. major components.
.bp .bp
*** INSERT FIGURE 3.7 HERE *** *** INSERT FIGURE 3.7 HERE ***
.PP
Self-sync or auto-sync bytes are Self-sync or auto-sync bytes are
special bytes that make up the three special bytes that make up the three
different types of gaps on a track. different types of gaps on a track.
@ -325,14 +325,14 @@ have been stripped out and 0's and
1's have been used for clarity. 1's have been used for clarity.
.sp1 .sp1
*** INSERT FIGURE 3.8 HERE *** *** INSERT FIGURE 3.8 HERE ***
.pp
There is no way from looking at the There is no way from looking at the
data to tell what bytes are data to tell what bytes are
represented, because we don't know represented, because we don't know
where to start. This is exactly the where to start. This is exactly the
problem that self-sync bytes problem that self-sync bytes
overcome. overcome.
.pp
A self-sync byte is defined to be a A self-sync byte is defined to be a
hexadecimal FF with a special hexadecimal FF with a special
difference. It is, in fact, a 10 bit difference. It is, in fact, a 10 bit
@ -344,7 +344,7 @@ elsewhere on the disk and a self-sync
hex FF byte. hex FF byte.
.bp .bp
*** INSERT FIGURE 3.9 HERE *** *** INSERT FIGURE 3.9 HERE ***
.pp
A self-sync is generated by using a A self-sync is generated by using a
40 cycle (micro-second) loop while 40 cycle (micro-second) loop while
writing an FF. A bit is written writing an FF. A bit is written
@ -378,7 +378,7 @@ the data unless there is an error on
the track. the track.
.sp1 .sp1
*** INSERT FIGURE 3.10 *** *** INSERT FIGURE 3.10 ***
.PP
We can now discuss the particular We can now discuss the particular
portions of a track in detail. The portions of a track in detail. The
three gaps will be covered first. three gaps will be covered first.
@ -395,7 +395,7 @@ bytes must be maintained for
each gap type (as discussed earlier). each gap type (as discussed earlier).
The result is fairly uniform gap The result is fairly uniform gap
sizes within each particular track. sizes within each particular track.
.pp
Gap 1 is the first data written to a Gap 1 is the first data written to a
track during initialization. Its track during initialization. Its
purpose is twofold. The gap purpose is twofold. The gap
@ -422,7 +422,7 @@ as a Gap 3 type for Address Field
number 0 (See Figure 3.7 for number 0 (See Figure 3.7 for
clarity). clarity).
.bp .bp
.pp
Gap 2 appears after each Address Gap 2 appears after each Address
Field and before each Data Field. Field and before each Data Field.
Its length varies from five to ten bytes Its length varies from five to ten bytes
@ -474,7 +474,7 @@ byte. Figure 3.12 illustrates this.
*** INSERT FIGURE 3.11 HERE *** *** INSERT FIGURE 3.11 HERE ***
.SP1 .SP1
*** INSERT FIGURE 3.12 HERE *** *** INSERT FIGURE 3.12 HERE ***
.PP
Gap 3 appears after each Gap 3 appears after each
Data Field and before each Address Data Field and before each Address
Field. It is longer than Gap 2 and Field. It is longer than Gap 2 and
@ -498,7 +498,7 @@ the first part of the gap can be
overwritten or damaged. (See Figure overwritten or damaged. (See Figure
3.11 for clarity) 3.11 for clarity)
.bp .bp
.pp
An examination of the contents of the An examination of the contents of the
two types of fields is in order. two types of fields is in order.
The Address Field contains The Address Field contains
@ -516,7 +516,7 @@ detailed illustration is given in
Figure 3.13. Figure 3.13.
.sp1 .sp1
*** INSERT FIGURE 3.13 HERE *** *** INSERT FIGURE 3.13 HERE ***
.PP
The prologue consists of three bytes The prologue consists of three bytes
which form a unique sequence, found which form a unique sequence, found
in no other component of the track. in no other component of the track.
@ -552,7 +552,7 @@ that the drive is still in sync with
the bytes on the disk. These bytes the bytes on the disk. These bytes
are probably unnecessary, but do are probably unnecessary, but do
provide a means of double checking. provide a means of double checking.
.pp
The other field type is the Data The other field type is the Data
Field. Much like the Address Field, Field. Much like the Address Field,
it consists of a prologue, data, it consists of a prologue, data,

35
D1S1/CH3.2#064000.txt
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@ -1,6 +1,6 @@
.SP2 .SP2
DATA FIELD ENCODING DATA FIELD ENCODING
.pp
Due to Apple's hardware, it is not Due to Apple's hardware, it is not
possible to read all 256 possible possible to read all 256 possible
byte values from a diskette. byte values from a diskette.
@ -22,7 +22,7 @@ This amounts to about 88K of data per
diskette, or roughly 72K of space diskette, or roughly 72K of space
available to the user; typical for 5 available to the user; typical for 5
1/4 single density drives. 1/4 single density drives.
.pp
Fortunately, a second technique for Fortunately, a second technique for
writing data to diskette was devised writing data to diskette was devised
that allows 13 that allows 13
@ -39,7 +39,7 @@ track format used by DOS 3 through
DOS 3.2.1. The "5 and 3" scheme DOS 3.2.1. The "5 and 3" scheme
represented a hefty 33% increase over represented a hefty 33% increase over
comparable drives of the day. comparable drives of the day.
.pp
Currently, of course, DOS 3.3 Currently, of course, DOS 3.3
features 16 sectors per track and features 16 sectors per track and
provides a 23% increase in disk provides a 23% increase in disk
@ -52,7 +52,7 @@ was to the logic of the "state
machine" in the P6 PROM, now allowing machine" in the P6 PROM, now allowing
two consecutive zero bits in data two consecutive zero bits in data
bytes. bytes.
.pp
These three different encoding These three different encoding
techniques techniques
will now be covered in some detail. will now be covered in some detail.
@ -74,7 +74,7 @@ are all set to one to guarantee
meeting the two requirements. meeting the two requirements.
.sp1 .sp1
*** INSERT FIGURE 3.15 HERE *** *** INSERT FIGURE 3.15 HERE ***
.PP
No matter what value the original No matter what value the original
data data byte has, this technique data data byte has, this technique
insures that the high bit is set and insures that the high bit is set and
@ -90,7 +90,7 @@ the byte containing the even bits.
This is illustrated in Figure 3.16. This is illustrated in Figure 3.16.
.sp1 .sp1
*** INSERT FIGURE 3.16 HERE *** *** INSERT FIGURE 3.16 HERE ***
.PP
It is important that the least It is important that the least
significant bit contain a 1 when the significant bit contain a 1 when the
odd-bits byte is left shifted. The odd-bits byte is left shifted. The
@ -98,7 +98,7 @@ entire
operation is carried out in the operation is carried out in the
RDADR subroutine at $B944 in DOS RDADR subroutine at $B944 in DOS
(48K). (48K).
.pp
The major difficulty with the above The major difficulty with the above
technique is that it takes up a lot of technique is that it takes up a lot of
room on the track. To overcome this room on the track. To overcome this
@ -126,7 +126,7 @@ An overview is diagrammed in Figure
3.17. 3.17.
.sp1 .sp1
*** INSERT FIGURE 3.17 HERE *** *** INSERT FIGURE 3.17 HERE ***
.PP
First, the 256 bytes that will make First, the 256 bytes that will make
up a sector must be translated to up a sector must be translated to
five bit bytes. This is done by the five bit bytes. This is done by the
@ -150,7 +150,7 @@ contains three areas, graphically
illustrating the name "5 and 3". illustrating the name "5 and 3".
.bp .bp
*** INSERT FIGURE 3.18 HERE *** *** INSERT FIGURE 3.18 HERE ***
.PP
A total of 410 bytes are needed to A total of 410 bytes are needed to
store the original 256. This can be store the original 256. This can be
calculated by finding the total bits calculated by finding the total bits
@ -166,7 +166,7 @@ involving a one to one look-up in the
table given in Figure 3.19. table given in Figure 3.19.
.sp1 .sp1
*** INSERT FIGURE 3.19 HERE *** *** INSERT FIGURE 3.19 HERE ***
.pp
The Data Field has a checksum much The Data Field has a checksum much
like the one in the Address Field, like the one in the Address Field,
used to verify the integrity of the used to verify the integrity of the
@ -181,7 +181,7 @@ Figure 3.19. This can best be
illustrated by Figure 3.20 on the following page. illustrated by Figure 3.20 on the following page.
.sp1 .sp1
*** INSERT FIGURE 3.20 HERE *** *** INSERT FIGURE 3.20 HERE ***
.PP
The reason for this transformation The reason for this transformation
can be better understood by examining can be better understood by examining
how the information is retrieved from how the information is retrieved from
@ -205,7 +205,7 @@ for that point in the series.
This process is diagrammed in Figure 3.21. This process is diagrammed in Figure 3.21.
.bp .bp
*** INSERT FIGURE 3.21 HERE *** *** INSERT FIGURE 3.21 HERE ***
.pp
The third encoding technique, currently The third encoding technique, currently
used by DOS 3.3, is similar to the "5 used by DOS 3.3, is similar to the "5
and 3". It was made possible by a and 3". It was made possible by a
@ -238,7 +238,7 @@ is done by the prenibble routine
results are shown in Figure 3.22. results are shown in Figure 3.22.
.sp1 .sp1
*** INSERT FIGURE 3.22 (20) HERE *** *** INSERT FIGURE 3.22 (20) HERE ***
.PP
A total of 342 bytes are needed, A total of 342 bytes are needed,
shown by finding the total number of shown by finding the total number of
bits (256 x 8 = 2048) and dividing by bits (256 x 8 = 2048) and dividing by
@ -255,7 +255,7 @@ of exclusive-ORs, exactly as with the
*** INSERT FIGURE 3.23 (21) HERE *** *** INSERT FIGURE 3.23 (21) HERE ***
.sp1 .sp1
SECTOR INTERLEAVING SECTOR INTERLEAVING
.PP
Sector interleaving is the staggering Sector interleaving is the staggering
of sectors on a track to maximize of sectors on a track to maximize
access speed. There is usually a access speed. There is usually a
@ -287,7 +287,7 @@ are stored in descending sequential
order, no single interleaving scheme order, no single interleaving scheme
works well for both booting and works well for both booting and
sequentially accessing a file. sequentially accessing a file.
.pp
A different approach has been used in A different approach has been used in
DOS 3.3 in an attempt to maximize DOS 3.3 in an attempt to maximize
performance. The interleaving is now performance. The interleaving is now
@ -309,7 +309,7 @@ problem if RWTS is used for disk
access, but would become a access, but would become a
consideration if access were made consideration if access were made
without RWTS. without RWTS.
.pp
To eliminate the access differences To eliminate the access differences
between booting and reading files, between booting and reading files,
another change has been made. During another change has been made. During
@ -319,7 +319,7 @@ order into memory, just as files are
accessed. This means one accessed. This means one
interleaving scheme can minimize disk interleaving scheme can minimize disk
access time. access time.
.pp
It is interesting to point out that It is interesting to point out that
Pascal, Fortran, and CP/M diskettes Pascal, Fortran, and CP/M diskettes
all use software interleaving also. all use software interleaving also.
@ -331,4 +331,3 @@ differences is presented in Figure
*** INSERT FIGURE 3.24 (22) HERE *** *** INSERT FIGURE 3.24 (22) HERE ***
.br .br
.nxch4 .nxch4
\x00

45
D1S1/CH4#064000.txt
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@ -2,7 +2,7 @@
.np .np
.ce .ce
CHAPTER 4 - DISKETTE DATA FORMATS CHAPTER 4 - DISKETTE DATA FORMATS
.pp
As was described in CHAPTER 3, a 16 As was described in CHAPTER 3, a 16
sector diskette consists of 560 data sector diskette consists of 560 data
areas of 256 bytes each, called areas of 256 bytes each, called
@ -12,7 +12,7 @@ rings or tracks of 16 sectors each.
The way DOS allocates these tracks of The way DOS allocates these tracks of
sectors is the subject of sectors is the subject of
this chapter. this chapter.
.pp
A file (be it APPLESOFT, A file (be it APPLESOFT,
INTEGER, BINARY, or TEXT type) INTEGER, BINARY, or TEXT type)
consists of one or more sectors consists of one or more sectors
@ -42,7 +42,7 @@ DOS uses sectors is given in Figure
*** INSERT FIGURE 4.1 *** *** INSERT FIGURE 4.1 ***
.sp1 .sp1
DISKETTE SPACE ALLOCATION DISKETTE SPACE ALLOCATION
.pp
The map in Figure 4.1 shows that the The map in Figure 4.1 shows that the
first three tracks of each diskette first three tracks of each diskette
are always reserved for the bootstrap are always reserved for the bootstrap
@ -80,7 +80,7 @@ track is allocated elsewhere on the
disk in the manner described above. disk in the manner described above.
.bp .bp
THE VTOC THE VTOC
.pp
The Volume Table Of Contents is the "anchor" of the The Volume Table Of Contents is the "anchor" of the
entire diskette. On any diskette entire diskette. On any diskette
accessible by any version of DOS, the accessible by any version of DOS, the
@ -146,7 +146,7 @@ BIT MAPS OF FREE SECTORS ON A GIVEN TRACK
If all sectors are free: If all sectors are free:
FFFF0000 FFFF0000
.pp
An example of a VTOC sector is given An example of a VTOC sector is given
in Figure 4.2. This VTOC corresponds in Figure 4.2. This VTOC corresponds
to the map of the diskette given in to the map of the diskette given in
@ -156,7 +156,7 @@ Figure 4.1.
.bp .bp
THE CATALOG THE CATALOG
.ll30 .ll30
.pp
In order for DOS to find a given In order for DOS to find a given
file, it must first read the VTOC to file, it must first read the VTOC to
find out where the first catalog find out where the first catalog
@ -189,7 +189,7 @@ that there are no more catalog
sectors in the chain. sectors in the chain.
.SP1 .SP1
*** INSERT FIGURE 4.3 *** *** INSERT FIGURE 4.3 ***
.PP
In each catalog In each catalog
sector up to seven files may be sector up to seven files may be
listed and described. Thus, on a listed and described. Thus, on a
@ -251,7 +251,7 @@ BYTE DESCRIPTION
this length giving 1-255 but a full 65,535 may be this length giving 1-255 but a full 65,535 may be
stored here. stored here.
.sp .sp
.pp
Figure 4.4 is an example of a typical Figure 4.4 is an example of a typical
catalog sector. In this example there catalog sector. In this example there
are only four files on the entire are only four files on the entire
@ -264,7 +264,7 @@ and contain zeros.
*** INSERT FIGURE 4.4 *** *** INSERT FIGURE 4.4 ***
.SP1 .SP1
THE TRACK/SECTOR LIST THE TRACK/SECTOR LIST
.PP
Each file has Each file has
associated with it a "Track/Sector associated with it a "Track/Sector
List" sector. This sector contains a List" sector. This sector contains a
@ -309,7 +309,7 @@ BYTE DESCRIPTION
0E-0F Track and sector of second data sector or zeros 0E-0F Track and sector of second data sector or zeros
10-FF Up to 120 more Track/Sector pairs 10-FF Up to 120 more Track/Sector pairs
.sp1 .sp1
.pp
A sequential file will end when the first zero T/S List entry A sequential file will end when the first zero T/S List entry
is encountered. A random file, however, can have spaces within is encountered. A random file, however, can have spaces within
it which were never allocated and therefore it which were never allocated and therefore
@ -318,7 +318,7 @@ in the T/S List. This distinction is not always handled
correctly by DOS. The VERIFY command, for instance, stops when correctly by DOS. The VERIFY command, for instance, stops when
it gets to the first zero T/S List entry and can not be used it gets to the first zero T/S List entry and can not be used
to verify some random organization text files. to verify some random organization text files.
.pp
An example T/S List sector is given in Figure 4.6. An example T/S List sector is given in Figure 4.6.
The example file (HELLO, from our The example file (HELLO, from our
previous examples) has only one data previous examples) has only one data
@ -352,7 +352,7 @@ that the data was broken up into
sectors at all. sectors at all.
.SP1 .SP1
TEXT FILES TEXT FILES
.pp
The TEXT data type is the least The TEXT data type is the least
complicated complicated
file data structure. It consists of file data structure. It consists of
@ -393,7 +393,7 @@ file.
*** INSERT FIGURE 4.7 *** *** INSERT FIGURE 4.7 ***
.bp .bp
BINARY FILES BINARY FILES
.pp
The structure of a BINARY type file is The structure of a BINARY type file is
shown in Figure 4.8. An exact copy of shown in Figure 4.8. An exact copy of
the memory involved is written to the the memory involved is written to the
@ -423,7 +423,7 @@ the diskette.
*** INSERT FIGURE 4.8 *** *** INSERT FIGURE 4.8 ***
.SP1 .SP1
APPLESOFT AND INTEGER FILES APPLESOFT AND INTEGER FILES
.pp
A BASIC program, be it APPLESOFT or A BASIC program, be it APPLESOFT or
INTEGER, is saved to the diskette in INTEGER, is saved to the diskette in
a way that is similar to BSAVE. The a way that is similar to BSAVE. The
@ -457,7 +457,7 @@ BASIC program is given in Figure
*** INSERT FIGURES 4.9 AND 4.10 *** *** INSERT FIGURES 4.9 AND 4.10 ***
.bp .bp
OTHER FILE TYPES (S,R,A,B) OTHER FILE TYPES (S,R,A,B)
.pp
Additional file types have been Additional file types have been
defined within DOS as can be seen in defined within DOS as can be seen in
the file descriptive entry format, the file descriptive entry format,
@ -485,7 +485,7 @@ about R files he should refer to that
documentation. documentation.
.sp1 .sp1
EMERGENCY REPAIRS EMERGENCY REPAIRS
.PP
From time to time the information on From time to time the information on
a diskette can become damaged or a diskette can become damaged or
lost. This can create various lost. This can create various
@ -499,7 +499,7 @@ and a few program tools can allow any
reasonably sharp APPLE II user to reasonably sharp APPLE II user to
patch up most errors on his patch up most errors on his
diskettes. diskettes.
.pp
A first question would be, "how do A first question would be, "how do
errors occur". The most common cause errors occur". The most common cause
of an error is a worn or physically of an error is a worn or physically
@ -517,7 +517,7 @@ the files on
the aged diskette to a brand new one the aged diskette to a brand new one
and discards the old one or keeps it and discards the old one or keeps it
as a backup. as a backup.
.pp
Another cause of damaged diskettes is Another cause of damaged diskettes is
the practice of hitting the RESET key the practice of hitting the RESET key
to abort the execution of a program to abort the execution of a program
@ -553,7 +553,7 @@ checksum (see CHAPTER 3) it may be
possible to read the bad sector and possible to read the bad sector and
ignore the error and get most of the ignore the error and get most of the
data. data.
.pp
An I/O error usually means that one An I/O error usually means that one
of two conditions has occured. Either of two conditions has occured. Either
a bad checksum was detected on the a bad checksum was detected on the
@ -571,7 +571,7 @@ to copy all readable sectors from the
damaged diskette to another formatted damaged diskette to another formatted
diskette and then reconstruct the diskette and then reconstruct the
lost data there. lost data there.
.pp
Many commercially available utilities Many commercially available utilities
exist which allow the user to exist which allow the user to
read and display the contents of read and display the contents of
@ -616,7 +616,7 @@ files periodically to simplify
recovery. More information on the recovery. More information on the
above procedures is given in APPENDIX above procedures is given in APPENDIX
A. A.
.pp
A less significant form of diskette A less significant form of diskette
clobber, but very annoying, is the clobber, but very annoying, is the
loss of free sectors. Since DOS loss of free sectors. Since DOS
@ -644,7 +644,7 @@ another diskette (note that FID must
be used, not COPY, since COPY copies be used, not COPY, since COPY copies
an image of the diskette, bad VTOC an image of the diskette, bad VTOC
and all). and all).
.pp
If a file is deleted it can usually If a file is deleted it can usually
be recovered, providing that be recovered, providing that
additional sector allocations have additional sector allocations have
@ -661,4 +661,3 @@ and then the original deleted so that
the VTOC freespace bit map will the VTOC freespace bit map will
be updated. be updated.
.nx ch5 .nx ch5
\x00

21
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@ -4,7 +4,7 @@
CHAPTER 5 - THE STRUCTURE OF DOS CHAPTER 5 - THE STRUCTURE OF DOS
.sp 2 .sp 2
DOS MEMORY USE DOS MEMORY USE
.pp
DOS is an assembly language program DOS is an assembly language program
which is loaded into RAM memory when which is loaded into RAM memory when
the user boots his disk. If the the user boots his disk. If the
@ -39,7 +39,7 @@ occupied does not exist on a smaller
machine. machine.
.SP1 .SP1
*** INSERT FIGURE 5.1 *** *** INSERT FIGURE 5.1 ***
.pp
A diagram of DOS's memory for a 48K A diagram of DOS's memory for a 48K
APPLE II is given in APPLE II is given in
Figure 5.1. As can be seen, there are Figure 5.1. As can be seen, there are
@ -58,7 +58,7 @@ the file buffers also changes. This
affects the placement of HIMEM, affects the placement of HIMEM,
moving it up or down with fewer or moving it up or down with fewer or
more buffers respectively. more buffers respectively.
.pp
The 3.5K The 3.5K
above the file buffers is occupied by above the file buffers is occupied by
the main DOS routines. It is here the main DOS routines. It is here
@ -86,7 +86,7 @@ of DOS. This interface is generalized
through a group of vectors in page 3 through a group of vectors in page 3
of RAM and is documented in the next of RAM and is documented in the next
chapter. chapter.
.pp
The last 2.5K of DOS is the The last 2.5K of DOS is the
Read/Write Track/Sector (RWTS) Read/Write Track/Sector (RWTS)
package. RWTS is the next step lower package. RWTS is the next step lower
@ -107,7 +107,7 @@ the next chapter.
.ne5 .ne5
THE DOS VECTORS IN PAGE 3 THE DOS VECTORS IN PAGE 3
.ll30 .ll30
.pp
In addition to the approximately 10K In addition to the approximately 10K
of RAM occupied by DOS in high of RAM occupied by DOS in high
memory, DOS maintains a group of what memory, DOS maintains a group of what
@ -199,7 +199,7 @@ ADDR USAGE
a maskable interrupt occurs. a maskable interrupt occurs.
.bp .bp
WHAT HAPPENS DURING BOOTING WHAT HAPPENS DURING BOOTING
.PP
When an APPLE is powered on its When an APPLE is powered on its
memory is essentially devoid of any memory is essentially devoid of any
programs. In order to get DOS programs. In order to get DOS
@ -218,7 +218,7 @@ in Figure 5.2 and a description of
the bootstrap process follows. the bootstrap process follows.
.SP1 .SP1
*** INSERT FIGURE 5.2 *** *** INSERT FIGURE 5.2 ***
.pp
The first boot stage (let's call it The first boot stage (let's call it
Boot 0) is the execution of the ROM Boot 0) is the execution of the ROM
on the disk controller card. When the on the disk controller card. When the
@ -242,7 +242,7 @@ $300). Once this sector is read, the
first stage boot jumps (GOTO's) $800 first stage boot jumps (GOTO's) $800
which is the second stage boot (Boot which is the second stage boot (Boot
1). 1).
.pp
Boot 1, also about 256 bytes long, Boot 1, also about 256 bytes long,
uses part of the Boot 0 ROM as a uses part of the Boot 0 ROM as a
subroutine and, in a loop, reads the subroutine and, in a loop, reads the
@ -336,7 +336,7 @@ that it will execute properly at its
new home. The relocator then jumps to new home. The relocator then jumps to
the high memory copy of DOS and the the high memory copy of DOS and the
old image is forgotten. old image is forgotten.
.pp
The DOS boot is completed by the DOS The DOS boot is completed by the DOS
coldstart routine. This code coldstart routine. This code
initializes DOS, making space for the initializes DOS, making space for the
@ -363,7 +363,7 @@ form of nibbilization (see chapter 3)
than any other sector on the than any other sector on the
diskette, making its raw appearance diskette, making its raw appearance
in memory at $3600 non-executable. in memory at $3600 non-executable.
.pp
The various stages of the bootstrap The various stages of the bootstrap
process will be covered again in greater process will be covered again in greater
detail in Chapter 8, DOS PROGRAM detail in Chapter 8, DOS PROGRAM
@ -372,4 +372,3 @@ LOGIC.
*** INSERT FIGURE 5.3 HERE *** *** INSERT FIGURE 5.3 HERE ***
.BR .BR
.NX CH6.1 .NX CH6.1
\x00

21
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@ -4,7 +4,7 @@
CHAPTER 6 - USING DOS FROM ASSEMBLY LANGUAGE CHAPTER 6 - USING DOS FROM ASSEMBLY LANGUAGE
.sp1 .sp1
CAVEAT CAVEAT
.PP
This chapter is aimed at the advanced This chapter is aimed at the advanced
assembly language programmer who assembly language programmer who
wishes to access the disk without wishes to access the disk without
@ -17,7 +17,7 @@ present) of a programmer who has
never used assembly language. never used assembly language.
.sp2 .sp2
DIRECT USE OF DISK DRIVE DIRECT USE OF DISK DRIVE
.PP
It is often desirable or necessary to It is often desirable or necessary to
access the Apple's disk drives access the Apple's disk drives
directly from assembly language, directly from assembly language,
@ -78,7 +78,7 @@ generally desirable to write code
that is not slot dependent, one would that is not slot dependent, one would
normally use $C08A,X (where the normally use $C08A,X (where the
X register contains the value $s0). X register contains the value $s0).
.pp
In general, the above addresses need In general, the above addresses need
only be accessed with any valid 6502 only be accessed with any valid 6502
instruction. However, in the case of instruction. However, in the case of
@ -92,7 +92,7 @@ number 1. (Assume slot number 6)
LDA $C0EA LDA $C0EA
BIT $C08A,X (where X-reg contains $60) BIT $C08A,X (where X-reg contains $60)
CMP $C08A,X (where X-reg contains $60) CMP $C08A,X (where X-reg contains $60)
.pp
Below are typical examples Below are typical examples
demonstrating the use of the device demonstrating the use of the device
address assignments. For more address assignments. For more
@ -101,7 +101,7 @@ assumed and the X-register contains
$60. $60.
.sp1 .sp1
STEPPER PHASE OFF/ON: STEPPER PHASE OFF/ON:
.PP
Basically, each of the four phases Basically, each of the four phases
(0-3) must be turned on and then off (0-3) must be turned on and then off
again. Done in ascending order, this again. Done in ascending order, this
@ -169,7 +169,7 @@ NOTE: $C08F,X must already have been
accessed to insure Write mode and a accessed to insure Write mode and a
100 microsecond delay should be 100 microsecond delay should be
invoked before writing. invoked before writing.
.pp
Due to hardware constraints, data Due to hardware constraints, data
bytes must be written in 32 cycle bytes must be written in 32 cycle
loops. Below is an example for an loops. Below is an example for an
@ -197,7 +197,7 @@ without an adjustment.
RTS (6) RTS (6)
.SP2 .SP2
CALLING READ/WRITE TRACK/SECTOR (RWTS) CALLING READ/WRITE TRACK/SECTOR (RWTS)
.pp
Read/Write Track/Sector (RWTS) exists Read/Write Track/Sector (RWTS) exists
in every version of DOS as a in every version of DOS as a
collection of subroutines, occupying collection of subroutines, occupying
@ -206,11 +206,11 @@ program. The interface to RWTS is
standardized and thoroughly documented by Apple standardized and thoroughly documented by Apple
and may be called by a and may be called by a
program running outside of DOS. program running outside of DOS.
.pp
There are two subroutines which must There are two subroutines which must
be called or whose function must be be called or whose function must be
performed. performed.
.pp
JSR $3E3 - When this subroutine is JSR $3E3 - When this subroutine is
called, the Y and A registers are called, the Y and A registers are
loaded with the address of the loaded with the address of the
@ -227,7 +227,7 @@ to RWTS. Of course, you may set up
your own IOB as long as the Y and A your own IOB as long as the Y and A
registers point to your IOB upon registers point to your IOB upon
calling RWTS. calling RWTS.
.pp
JSR $3D9 - This is the main entry to JSR $3D9 - This is the main entry to
the RWTS routine. Prior to making the RWTS routine. Prior to making
this call, the Y and A registers must this call, the Y and A registers must
@ -356,4 +356,3 @@ Output: Byte 0D - Return code (See previous definition)
10 - Current Drive number 10 - Current Drive number
.bp .bp
.nx ch6.2 .nx ch6.2
\x00

19
D1S1/CH6.2#064000.txt
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@ -1,5 +1,5 @@
CALLING THE DOS FILE MANAGER CALLING THE DOS FILE MANAGER
.pp
The DOS file manager exists in every The DOS file manager exists in every
version of DOS as a collection of version of DOS as a collection of
subroutines occupying approximately subroutines occupying approximately
@ -20,7 +20,7 @@ these routines may be relied upon as
program program
uses these routines to process files uses these routines to process files
on the diskette. on the diskette.
.pp
There are There are
two subroutines which must be called two subroutines which must be called
in order to access the file manager. in order to access the file manager.
@ -289,7 +289,7 @@ Input: Byte 00 - 0C
Output: Byte 0A - Return code Output: Byte 0A - Return code
.bp .bp
DOS BUFFERS DOS BUFFERS
.pp
Usually it is desirable to use one of DOS's buffers when Usually it is desirable to use one of DOS's buffers when
calling the file manager to save memory. DOS buffers consist of calling the file manager to save memory. DOS buffers consist of
each of the three buffers used by the file manager (file each of the three buffers used by the file manager (file
@ -336,7 +336,7 @@ BYTE DESCRIPTION
the chain then this field contains zeros. the chain then this field contains zeros.
.bp .bp
THE FILE MANAGER WORKAREA THE FILE MANAGER WORKAREA
.pp
The file manager workarea contains The file manager workarea contains
the variables which, taken together, the variables which, taken together,
constitute all of the information the constitute all of the information the
@ -398,13 +398,13 @@ BYTE DESCRIPTION
2A/2C Not used 2A/2C Not used
.bp .bp
COMMON ALGORITHMS COMMON ALGORITHMS
.PP
Given below are several pieces of code Given below are several pieces of code
which are used when working with DOS: which are used when working with DOS:
.SP1 .SP1
.ne5 .ne5
LOCATE A FREE DOS BUFFER LOCATE A FREE DOS BUFFER
.PP
The following subroutine may be used The following subroutine may be used
to locate an unallocated DOS buffer to locate an unallocated DOS buffer
for use with the DOS file manager. for use with the DOS file manager.
@ -438,7 +438,7 @@ NBUF SEC INDICATE-NO FREE BUFFERS
RTS RETURN TO CALLER RTS RETURN TO CALLER
.bp .bp
IS DOS IN THE MACHINE? IS DOS IN THE MACHINE?
.PP
The following series of instructions The following series of instructions
should be used prior to attempting to should be used prior to attempting to
call RWTS or the file manager to call RWTS or the file manager to
@ -452,7 +452,7 @@ machine.
.SP2 .SP2
.ne5 .ne5
WHICH VERSION OF DOS IS ACTIVE? WHICH VERSION OF DOS IS ACTIVE?
.pp
In case the program has version dependent code, a check of In case the program has version dependent code, a check of
the DOS version may be required: the DOS version may be required:
.sp1 .sp1
@ -498,7 +498,7 @@ SETBSC CMP $E000 CORRECT BASIC ALREADY THERE?
\x2c\x40\x42\x5b\x33\x03\x61\x9fTS RTS IN ANY CASE, EXIT TO CALLER \x2c\x40\x42\x5b\x33\x03\x61\x9fTS RTS IN ANY CASE, EXIT TO CALLER
.bp .bp
SEE IF A BASIC PROGRAM IS IN EXECUTION SEE IF A BASIC PROGRAM IS IN EXECUTION
.PP
To determine if there is a BASIC program running or To determine if there is a BASIC program running or
if BASIC is in immediate command mode, use the following if BASIC is in immediate command mode, use the following
statements: statements:
@ -519,4 +519,3 @@ statements:
BNE EXEC ELSE, PROGRAM IS EXECUTING BNE EXEC ELSE, PROGRAM IS EXECUTING
.br .br
.nx ch7 .nx ch7
\x00

13
D1S1/CH7#064000.txt
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@ -3,7 +3,7 @@
.ce .ce
CHAPTER 7 - CUSTOMIZING DOS CHAPTER 7 - CUSTOMIZING DOS
.sp1 .sp1
.PP
Although DOS usually provides most of Although DOS usually provides most of
the functionality needed by the BASIC the functionality needed by the BASIC
or assembly language programmer, at or assembly language programmer, at
@ -22,7 +22,7 @@ implications of each change can
result in an unreliable system. result in an unreliable system.
.sp1 .sp1
SLAVE VS MASTER PATCHING SLAVE VS MASTER PATCHING
.PP
The usual procedure for making The usual procedure for making
changes to DOS involves "patching" changes to DOS involves "patching"
the object or machine language code the object or machine language code
@ -78,7 +78,7 @@ DOS.
.SP1 .SP1
.ne5 .ne5
AVOIDING RELOAD OF LANGUAGE CARD AVOIDING RELOAD OF LANGUAGE CARD
.PP
A rather annoying addition to DOS 3.3 A rather annoying addition to DOS 3.3
was a patch to the Boot 2 code to was a patch to the Boot 2 code to
store a binary zero in the first byte store a binary zero in the first byte
@ -122,7 +122,7 @@ store instruction for a 32K DOS is
7FD3 and for a 16K DOS is 3FD3. 7FD3 and for a 16K DOS is 3FD3.
.sp1 .sp1
INSERTING A PROGRAM BETWEEN DOS AND ITS BUFFERS INSERTING A PROGRAM BETWEEN DOS AND ITS BUFFERS
.pp
Once in a while it is useful to find Once in a while it is useful to find
a "safe" place to load a machine a "safe" place to load a machine
language program (a printer driver, language program (a printer driver,
@ -154,7 +154,7 @@ since its HIMEM is below the DOS
buffers. buffers.
.bp .bp
BRUN OR EXEC THE HELLO FILE BRUN OR EXEC THE HELLO FILE
.pp
Ordinarily, when DOS finishes booting Ordinarily, when DOS finishes booting
into memory, it performs a RUN into memory, it performs a RUN
command on the HELLO file in its file command on the HELLO file in its file
@ -170,7 +170,7 @@ following patch to DOS (48K):
.sp1 .sp1
.ne5 .ne5
REMOVING THE PAUSE DURING A LONG CATALOG REMOVING THE PAUSE DURING A LONG CATALOG
.pp
Normally, when a CATALOG command is Normally, when a CATALOG command is
done on a disk with many files, DOS done on a disk with many files, DOS
will pause every time the screen will pause every time the screen
@ -186,4 +186,3 @@ patch to DOS (48K):
.bp .bp
.st waiting for ch8 diskette .st waiting for ch8 diskette
.nx ch8 .nx ch8
\x00

3
D1S2/CH8#064000.txt
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@ -12,7 +12,7 @@
.ce .ce
CHAPTER 8 - DOS PROGRAM LOGIC CHAPTER 8 - DOS PROGRAM LOGIC
.sp1 .sp1
.PP
This chapter will take a detailed This chapter will take a detailed
look at the operation of the DOS look at the operation of the DOS
program itself to aid the APPLE user program itself to aid the APPLE user
@ -377,4 +377,3 @@ ADDRESS
9FCD-A179 DOS command parse routine. 9FCD-A179 DOS command parse routine.
.br .br
.nx ch8.1 .nx ch8.1
\x00

1
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@ -163,4 +163,3 @@ A298-A2A2 APPEND command handler.
and turn flag off. and turn flag off.
Exit via a call to POSITION. Exit via a call to POSITION.
.nx ch8.2 .nx ch8.2
\x00

1
D1S2/CH8.2#064000.txt
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@ -218,4 +218,3 @@ A54F-A56D INIT command handler.
.np .np
A56E-A579 CATALOG command handler. A56E-A579 CATALOG command handler.
.nx ch8.3 .nx ch8.3
\x00

1
D1S2/CH8.3#064000.txt
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@ -219,4 +219,3 @@ A851-A883 Replace DOS keyboard/video intercept vectors.
address. address.
Exit to caller. Exit to caller.
.nx ch8.4 .nx ch8.4
\x00

1
D1S2/CH8.4#064000.txt
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@ -253,4 +253,3 @@ AB28-ABDB Common open routine.
And write it back (AF3A). And write it back (AF3A).
Set return code to 6 ("FILE NOT FOUND"). Set return code to 6 ("FILE NOT FOUND").
.nx ch8.5 .nx ch8.5
\x00

1
D1S2/CH8.5#064000.txt
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@ -278,4 +278,3 @@ AF34-AF4A Checkpoint write T/S List sector buffer to disk.
need of checkpoint. need of checkpoint.
Exit to caller. Exit to caller.
.nx ch8.6 .nx ch8.6
\x00

1
D1S2/CH8.6#064000.txt
View File

@ -406,4 +406,3 @@ B600-B6FF Start of Boot 2/RWTS image.
B6FF Number of sectors (pages) in Boot 2. B6FF Number of sectors (pages) in Boot 2.
.br .br
.nx ch8.7 .nx ch8.7
\x00

1
D1S2/CH8.7#064000.txt
View File

@ -402,4 +402,3 @@ BFED-BFFF Patch called from $B377.
Exit through $B385 ("DISK FULL ERROR"). Exit through $B385 ("DISK FULL ERROR").
.br .br
.nx ch8 zpage use .nx ch8 zpage use
\x00

1
D1S2/CH8.ZPAGE.USE#064000.txt
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@ -50,4 +50,3 @@ D6 APPLESOFT BASIC PROGRAM protection flag (DOS)
D8,D9 INTEGER BASIC line number (DOS) D8,D9 INTEGER BASIC line number (DOS)
APPLESOFT BASIC ONERR (DOS) APPLESOFT BASIC ONERR (DOS)
.br .br
\x00

1
D1S2/TABLE.OF.CONTEN#064000.txt
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@ -112,4 +112,3 @@ GLOSSARY
.SP3 .SP3
INDEX INDEX
.BR .BR
\x00

49
D2S1/APPENDIX.A#064000.txt
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@ -12,7 +12,7 @@
.ce .ce
APPENDIX A - EXAMPLE PROGRAMS APPENDIX A - EXAMPLE PROGRAMS
.sp1 .sp1
.PP
This section is intended to supply This section is intended to supply
the reader with utility programs the reader with utility programs
which can be used to examine and which can be used to examine and
@ -47,7 +47,7 @@ Five programs are provided:
DUMP TRACK DUMP UTILITY DUMP TRACK DUMP UTILITY
.pi8 .pi8
.in8 .in8
.pp
This is an example of how to directly This is an example of how to directly
access the disk drive through its I/O access the disk drive through its I/O
select addresses. DUMP may be used select addresses. DUMP may be used
@ -63,7 +63,7 @@ diskettes.
ZAP DISK UPDATE UTILITY ZAP DISK UPDATE UTILITY
.pi8 .pi8
.in8 .in8
.pp
This program is the backbone of any This program is the backbone of any
attempt to patch a diskette directory attempt to patch a diskette directory
back together. It is also useful in back together. It is also useful in
@ -81,7 +81,7 @@ Read/Write Track/Sector (RWTS).
INIT REFORMAT A SINGLE TRACK INIT REFORMAT A SINGLE TRACK
.pi8 .pi8
.in8 .in8
.pp
This program will initialize a single This program will initialize a single
track on a diskette. Any volume track on a diskette. Any volume
number ($00-$FF) may be specified. number ($00-$FF) may be specified.
@ -95,7 +95,7 @@ diskette. DOS 3.3 and 48K is assumed.
FTS FIND T/S LISTS UTILITY FTS FIND T/S LISTS UTILITY
.pi8 .pi8
.in8 .in8
.pp
FTS may be used when the directory FTS may be used when the directory
for a diskette has been destroyed. for a diskette has been destroyed.
It searches every sector on a It searches every sector on a
@ -111,7 +111,7 @@ together a new catalog using ZAP.
COPY CONVERT FILES COPY CONVERT FILES
.pi8 .pi8
.in8 .in8
.pp
COPY is provided as an example of COPY is provided as an example of
direct use of the DOS File Manager direct use of the DOS File Manager
package from assembly language. The package from assembly language. The
@ -146,7 +146,7 @@ non-assembly language programmer, the
binary object code of each program binary object code of each program
may be entered from the monitor using may be entered from the monitor using
the following procedure. the following procedure.
.pp
The assembly language listings The assembly language listings
consist of columns of information as consist of columns of information as
follows: follows:
@ -185,7 +185,7 @@ CALL -151 (Enter the monitor from BASIC)
0879:85 3F 0879:85 3F
087B:4C B3 FD 087B:4C B3 FD
BSAVE DUMP,A$800,L$7E (Save program to disk) BSAVE DUMP,A$800,L$7E (Save program to disk)
.pp
Note that if a line (such as line 4 Note that if a line (such as line 4
in DUMP) has no object bytes in DUMP) has no object bytes
associated with it, it may be associated with it, it may be
@ -210,7 +210,7 @@ BSAVE COPY,A$800,L$1EC
.bp .bp
DUMP -- TRACK DUMP UTILITY DUMP -- TRACK DUMP UTILITY
.sp1 .sp1
.pp
The DUMP program will dump any track The DUMP program will dump any track
on a diskette in its raw, on a diskette in its raw,
pre-nibbilized format, allowing the pre-nibbilized format, allowing the
@ -231,7 +231,7 @@ as an example of direct use of the
DISK II hardware from assembly DISK II hardware from assembly
language, with little or no use of language, with little or no use of
DOS. DOS.
.pp
To use DUMP, first store the number To use DUMP, first store the number
of the track you wish dumped at of the track you wish dumped at
location $02, then begin execution at location $02, then begin execution at
@ -257,7 +257,7 @@ The output might look like this...
1010- 9E FF FF FF FF FF D5 AA (Start of sector data) 1010- 9E FF FF FF FF FF D5 AA (Start of sector data)
1018- AD AE B2 9D AC AE 96 96 (Sector data) 1018- AD AE B2 9D AC AE 96 96 (Sector data)
...etc... ...etc...
.pp
Quite often, a sector with an I/O Quite often, a sector with an I/O
error will have only one bit which is error will have only one bit which is
in error, either in the address or in error, either in the address or
@ -273,7 +273,7 @@ is necessary to accomplish this feat.
.bp .bp
ZAP -- DISK UPDATE UTILITY ZAP -- DISK UPDATE UTILITY
.sp1 .sp1
.pp
The next step up the ladder from DUMP The next step up the ladder from DUMP
is to access data on the diskette at is to access data on the diskette at
the sector level. The ZAP program the sector level. The ZAP program
@ -288,7 +288,7 @@ when it is necessary to patch up a
damaged directory. Its use in this damaged directory. Its use in this
regard will be covered in more detail regard will be covered in more detail
when FTS is explained. when FTS is explained.
.pp
To use ZAP, store the number of the To use ZAP, store the number of the
track and sector you wish to access track and sector you wish to access
in $02 and $03 respectively. Tracks in $02 and $03 respectively. Tracks
@ -327,7 +327,7 @@ The output might look like this...
0810- 00 00 00 00 00 00 00 00 0810- 00 00 00 00 00 00 00 00
0818- 00 00 00 00 00 00 00 00 0818- 00 00 00 00 00 00 00 00
...etc... ...etc...
.pp
In the above example, if the byte at In the above example, if the byte at
offset 3 (the version of DOS which offset 3 (the version of DOS which
INITed this diskette) is to be INITed this diskette) is to be
@ -342,7 +342,7 @@ Note that ZAP will remember the
previous previous
values in $02, $03, and $04. values in $02, $03, and $04.
.bp .bp
.pp
If something is wrong with the sector If something is wrong with the sector
to be read (an I/O error, perhaps), to be read (an I/O error, perhaps),
ZAP will print an error message of ZAP will print an error message of
@ -362,7 +362,7 @@ these errors.
.bp .bp
INIT -- REFORMAT A SINGLE TRACK INIT -- REFORMAT A SINGLE TRACK
.sp1 .sp1
.pp
Occasionally the sectoring information Occasionally the sectoring information
on a diskette can become damaged so on a diskette can become damaged so
that one or more sectors can no that one or more sectors can no
@ -387,7 +387,7 @@ run they can be copied back to the
repaired diskette and data can be repaired diskette and data can be
written to the previously damaged written to the previously damaged
sector. sector.
.pp
To run INIT, first store the number To run INIT, first store the number
of the track you wish reformatted at of the track you wish reformatted at
location $02, the volume number of location $02, the volume number of
@ -418,7 +418,7 @@ sizes.
.bp .bp
FTS -- FIND T/S LISTS UTILITY FTS -- FIND T/S LISTS UTILITY
.sp1 .sp1
.pp
From time to time one of your From time to time one of your
diskettes will develop an I/O error diskettes will develop an I/O error
smack in the middle of the catalog smack in the middle of the catalog
@ -456,7 +456,7 @@ necessary to restore all the files
and copy them to another diskette, and copy them to another diskette,
and later delete the duplicate or and later delete the duplicate or
unwanted ones. unwanted ones.
.pp
To run FTS, simply load the program To run FTS, simply load the program
and start execution at $900. FTS and start execution at $900. FTS
will print the track and sector will print the track and sector
@ -477,7 +477,7 @@ T=13 S=0F
T=14 S=0D T=14 S=0D
T=14 S=0F T=14 S=0F
.bp .bp
.pp
Here, only four possible files were Here, only four possible files were
found. ZAP should now be used to found. ZAP should now be used to
read track $12, sector $0F. At +$0C read track $12, sector $0F. At +$0C
@ -523,7 +523,7 @@ BLOAD ZAP
:A0 A0 :A0 A0
02:11 0F 02 N 900G (Write new sector image out as 02:11 0F 02 N 900G (Write new sector image out as
first (and only) catalog sector) first (and only) catalog sector)
.pp
The file should immediately be copied The file should immediately be copied
to another diskette and then the to another diskette and then the
process repeated for each T/S List process repeated for each T/S List
@ -537,7 +537,7 @@ damaged disk may be re-INITialized.
.bp .bp
COPY -- CONVERT FILES COPY -- CONVERT FILES
.sp1 .sp1
.pp
The COPY program demonstrates the use The COPY program demonstrates the use
of the DOS File Manager subroutine of the DOS File Manager subroutine
package from assembly language. COPY package from assembly language. COPY
@ -553,7 +553,7 @@ name of the output file is "OUTPUT".
COPY is a single drive operation, COPY is a single drive operation,
using the last drive which was using the last drive which was
referenced. referenced.
.pp
To run COPY, load it and begin To run COPY, load it and begin
execution at $800: execution at $800:
.sp1 .sp1
@ -562,7 +562,7 @@ CALL -151 (Get into the monitor from BASIC)
BLOAD COPY (Load the COPY program) BLOAD COPY (Load the COPY program)
...Now insert the disk containing INPUT... ...Now insert the disk containing INPUT...
900G (Run the COPY program) 900G (Run the COPY program)
.pp
When COPY finishes, it will return to When COPY finishes, it will return to
BASIC. If any errors occur, the BASIC. If any errors occur, the
return code passed back from the File return code passed back from the File
@ -572,4 +572,3 @@ parameter list in Chapter 6
for a list of these return codes. for a list of these return codes.
.br .br
.nx appendix b .nx appendix b
\x00

27
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@ -3,7 +3,7 @@
.ce .ce
APPENDIX B - DISK PROTECTION SCHEMES APPENDIX B - DISK PROTECTION SCHEMES
.sp1 .sp1
.PP
As the quantity and quality As the quantity and quality
of Apple II software of Apple II software
has increased, so has the incidence has increased, so has the incidence
@ -16,7 +16,7 @@ schemes involve a modified or custom
Disk Operating System, it seems Disk Operating System, it seems
appropriate to discuss disk appropriate to discuss disk
protection in general. protection in general.
.pp
Typically, a protection scheme's Typically, a protection scheme's
purpose is to stop unauthorized purpose is to stop unauthorized
duplication of the contents of the duplication of the contents of the
@ -31,7 +31,7 @@ the reader is unclear about how a
normal diskette is formatted, he normal diskette is formatted, he
should refer to Chapter 3 for more should refer to Chapter 3 for more
information. information.
.pp
Early protection methods were Early protection methods were
primitive in comparison to what is primitive in comparison to what is
being done now. Just as the methods being done now. Just as the methods
@ -43,7 +43,7 @@ are developed, they are soon broken,
prompting the software vendor to try prompting the software vendor to try
to create even more sophisticated to create even more sophisticated
systems. systems.
.pp
It seems reasonable at this time to It seems reasonable at this time to
say that it is impossible to protect say that it is impossible to protect
a disk in such a way that it can't be a disk in such a way that it can't be
@ -68,14 +68,14 @@ which take advantage of this
are limited and must are limited and must
involve only certain changes which involve only certain changes which
will be discussed below. will be discussed below.
.pp
Most protected disks use a modified Most protected disks use a modified
version of Apple's DOS. This is a version of Apple's DOS. This is a
much easier task than writing one's much easier task than writing one's
own Disk Operating System and will be own Disk Operating System and will be
the primary area covered by this the primary area covered by this
discussion. discussion.
.pp
Although there are a vast array of Although there are a vast array of
different protection schemes, they different protection schemes, they
all consist of having some portion of all consist of having some portion of
@ -87,7 +87,7 @@ number of bytes which, if changed,
will cause a sector to be unreadable. will cause a sector to be unreadable.
We will examine how that is done in We will examine how that is done in
some detail. some detail.
.pp
The Address Field normally starts The Address Field normally starts
with the bytes $D5/$AA/$96. If any with the bytes $D5/$AA/$96. If any
one of these bytes were changed, DOS one of these bytes were changed, DOS
@ -122,7 +122,7 @@ whatever two bytes follow the
information field, using them for information field, using them for
verification, but not to locate the verification, but not to locate the
field itself. field itself.
.pp
The Data Field is quite similar to The Data Field is quite similar to
the Address Field in that its three the Address Field in that its three
parts correspond almost identically, parts correspond almost identically,
@ -141,7 +141,7 @@ that the checksum computation will be
non-zero, causing an error. The non-zero, causing an error. The
closing bytes are identical to those closing bytes are identical to those
of the Address Field ($DE/$AA). of the Address Field ($DE/$AA).
.pp
As mentioned earlier, the PROM on the As mentioned earlier, the PROM on the
disk controller skips certain parts disk controller skips certain parts
of both types of fields. In of both types of fields. In
@ -155,7 +155,7 @@ defeated by making slight
modifications to DOS's RWTS modifications to DOS's RWTS
routines, rendering it routines, rendering it
unreliable as a protective measure. unreliable as a protective measure.
.pp
In the early days of disk protection, In the early days of disk protection,
a single alteration was all that was a single alteration was all that was
needed to stop all but a few from needed to stop all but a few from
@ -171,7 +171,7 @@ non-standard formats written even
.ul .ul
between between
tracks. tracks.
.pp
A state of the art protection scheme A state of the art protection scheme
consists of two elements. First, the consists of two elements. First, the
data is stored on the diskette in data is stored on the diskette in
@ -184,7 +184,7 @@ text page or certain zero page
locations) This is to prevent the locations) This is to prevent the
software from being removed from software from being removed from
memory intact. memory intact.
.pp
Recently, several "nibble" or byte Recently, several "nibble" or byte
copy programs have become available. copy programs have become available.
Unlike traditional copy programs Unlike traditional copy programs
@ -239,7 +239,7 @@ hardware device to help find the sync
bytes, a software program must make bytes, a software program must make
some assumptions about how the data some assumptions about how the data
is structured on the diskette. is structured on the diskette.
.pp
The result of the The result of the
introduction of nibble copy programs introduction of nibble copy programs
has been to "force the hand" of the has been to "force the hand" of the
@ -260,4 +260,3 @@ techniques cannot be used to defeat
them. them.
.br .br
.nx appendix c.1 .nx appendix c.1
\x00

205
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@ -7,12 +7,12 @@ APPENDIX C - GLOSSARY
.pn5 .pn5
.IN20 .IN20
.PI-20 .PI-20
.PP
ACCESS TIME]>The time required to ACCESS TIME]>The time required to
locate and read or write data on a locate and read or write data on a
direct access storage device, such as direct access storage device, such as
a diskette drive. a diskette drive.
.pp
ADDRESS]>The numeric location of a ADDRESS]>The numeric location of a
piece of data in memory. Usually piece of data in memory. Usually
given as a hexadecimal number from given as a hexadecimal number from
@ -20,33 +20,33 @@ $0000 to $FFFF (65535 decimal). A
disk address is the location of a disk address is the location of a
data sector, expressed in terms of its data sector, expressed in terms of its
track and sector numbers. track and sector numbers.
.pp
ALGORITHM]>A sequence of steps which ALGORITHM]>A sequence of steps which
may be performed by a program or may be performed by a program or
other process, which will produce a other process, which will produce a
given result. given result.
.pp
ALPHANUMERIC]>An alphabetic character ALPHANUMERIC]>An alphabetic character
(A-Z) or a numeric digit (0-9). The (A-Z) or a numeric digit (0-9). The
term used to refer to the class of all term used to refer to the class of all
characters and digits. characters and digits.
.pp
ANALOG]>As opposed to digital. ANALOG]>As opposed to digital.
Having a value which is continuous, Having a value which is continuous,
such as a voltage or electrical such as a voltage or electrical
resistance. resistance.
.pp
AND]>The logical process of AND]>The logical process of
determining whether two bits are both determining whether two bits are both
ones. 0 AND 1 results in 0 (false), ones. 0 AND 1 results in 0 (false),
1 AND 1 results in 1 (true). 1 AND 1 results in 1 (true).
.pp
ARM]>The portion of a disk drive ARM]>The portion of a disk drive
which suspends the read/write head which suspends the read/write head
over the disk's surface. The arm can over the disk's surface. The arm can
be moved radially to allow access to be moved radially to allow access to
different tracks. different tracks.
.pp
ASCII]>American Standard Code for ASCII]>American Standard Code for
Information Interchange. A Information Interchange. A
hexadecimal to character conversion hexadecimal to character conversion
@ -57,7 +57,7 @@ special, or control character. ASCII
is used when interfacing to is used when interfacing to
peripherals, such as keyboards, peripherals, such as keyboards,
printers, or video text displays. printers, or video text displays.
.pp
ASSEMBLY LANGUAGE]>Also known as ASSEMBLY LANGUAGE]>Also known as
MACHINE LANGUAGE. The native MACHINE LANGUAGE. The native
programming language of the programming language of the
@ -67,40 +67,40 @@ and is not humanized, as is BASIC,
PASCAL, or FORTRAN. An assembler is PASCAL, or FORTRAN. An assembler is
used to convert assembly language used to convert assembly language
statements to an executable program. statements to an executable program.
.pp
BACKUP]>The process of making a copy BACKUP]>The process of making a copy
of a program or data against the of a program or data against the
possibility of its accidental loss or possibility of its accidental loss or
destruction. destruction.
.pp
BASE]>The number system in use. BASE]>The number system in use.
Decimal is base 10, since each digit Decimal is base 10, since each digit
represents a power of 10 represents a power of 10
(1,10,100,...). Hexadecimal is base (1,10,100,...). Hexadecimal is base
16 (1,16,256,...). Binary is base 2 16 (1,16,256,...). Binary is base 2
(1,2,4,8,...). (1,2,4,8,...).
.pp
BINARY]>A number system based upon BINARY]>A number system based upon
powers of 2. Only the digits 0 and 1 powers of 2. Only the digits 0 and 1
are used. 101 in binary, for are used. 101 in binary, for
example, is 1 units digit, 0 twos, example, is 1 units digit, 0 twos,
and 1 fours, or 5 in decimal. and 1 fours, or 5 in decimal.
.pp
BIT]>A single binary digit (a 1 or a BIT]>A single binary digit (a 1 or a
0). A bit is the smallest unit of 0). A bit is the smallest unit of
storage or information in a computer. storage or information in a computer.
.PP
BIT CELL]>The space on a diskette, BIT CELL]>The space on a diskette,
between two clock pulses, which can between two clock pulses, which can
hold the value of a single binary 0 hold the value of a single binary 0
or 1 (bit). or 1 (bit).
.pp
BIT SLIP MARKS]>The epilogue of a BIT SLIP MARKS]>The epilogue of a
disk field. Used to double check disk field. Used to double check
that the disk head is still in read that the disk head is still in read
sync and the sector has not been sync and the sector has not been
damaged. damaged.
.pp
BOOT/BOOTSTRAP]>The process of BOOT/BOOTSTRAP]>The process of
loading a very large program into loading a very large program into
memory by loading successively larger memory by loading successively larger
@ -108,50 +108,50 @@ pieces, each of which loads its
successor. The program loads itself successor. The program loads itself
by "pulling itself up by its by "pulling itself up by its
bootstraps". bootstraps".
.pp
BRK]>BREAK. An assembly langauge instruction BRK]>BREAK. An assembly langauge instruction
which can be used to force an which can be used to force an
interrupt and immediate suspension of interrupt and immediate suspension of
execution of a program. execution of a program.
.pp
BUFFER]>An area of memory used to BUFFER]>An area of memory used to
temporarily hold data as it is being temporarily hold data as it is being
transferred to or from a peripheral, transferred to or from a peripheral,
such as a disk drive. such as a disk drive.
.pp
BUG]>A programming error. Faulty BUG]>A programming error. Faulty
operation of a program. operation of a program.
.pp
BYTE]>The smallest unit of BYTE]>The smallest unit of
addressable memory in a computer. A addressable memory in a computer. A
byte usually consists of 8 bits and byte usually consists of 8 bits and
can contain a decimal number ranging can contain a decimal number ranging
from 0 to 255 or a single from 0 to 255 or a single
alphanumeric character. alphanumeric character.
.pp
CARRIAGE RETURN]>A control character CARRIAGE RETURN]>A control character
which instructs the printer to end which instructs the printer to end
one line and begin another. When one line and begin another. When
printing a carriage return is usually printing a carriage return is usually
followed by a line feed. followed by a line feed.
.pp
CARRY FLAG]>A 6502 processor flag CARRY FLAG]>A 6502 processor flag
which indicates that a previous which indicates that a previous
addition resulted in a carry. Also addition resulted in a carry. Also
used used
as an error indicator by many system as an error indicator by many system
programs. programs.
.PP
CATALOG]>A directory of the files on CATALOG]>A directory of the files on
a diskette. See DIRECTORY. a diskette. See DIRECTORY.
.pp
CHAIN]>A linked list of data CHAIN]>A linked list of data
elements. Data is chained if its elements. Data is chained if its
elements need not be contiguous in elements need not be contiguous in
storage and storage and
each element can be found from its each element can be found from its
predecessor via an address pointer. predecessor via an address pointer.
.pp
CHECKSUM/CRC]>A method for verifying CHECKSUM/CRC]>A method for verifying
that data has not been damaged. When that data has not been damaged. When
data is written, the sum of all its data is written, the sum of all its
@ -159,34 +159,34 @@ constituent bytes is stored with it.
If, when the data is later read, its If, when the data is later read, its
sum no longer matches the checksum, sum no longer matches the checksum,
it has been damaged. it has been damaged.
.pp
CLOBBERED]>Damaged or destroyed. A CLOBBERED]>Damaged or destroyed. A
clobbered sector is one which has clobbered sector is one which has
been overwritten such that it is been overwritten such that it is
unrecoverable. unrecoverable.
.pp
CODE]>Executable instructions to the CODE]>Executable instructions to the
computer, usually in machine computer, usually in machine
language. language.
.pp
COLDSTART]>A restart of a program COLDSTART]>A restart of a program
which reinitializes all of its which reinitializes all of its
parameters, usually erasing any work parameters, usually erasing any work
which was in progress at the time of which was in progress at the time of
the restart. A DOS coldstart erases the restart. A DOS coldstart erases
the BASIC program in memory. the BASIC program in memory.
.pp
CONTIGUOUS]>Physically next to. Two CONTIGUOUS]>Physically next to. Two
bytes are contiguous if they are bytes are contiguous if they are
adjoining each other in memory or on adjoining each other in memory or on
the disk. the disk.
.pp
CONTROL BLOCK]>A collection of data CONTROL BLOCK]>A collection of data
which is used by the operating system which is used by the operating system
to manage resources. Examples of a to manage resources. Examples of a
control block used by DOS are the control block used by DOS are the
file buffers. file buffers.
.pp
CONTROL CHARACTER]>A special ASCII CONTROL CHARACTER]>A special ASCII
code which is used to perform a code which is used to perform a
unique function on a peripheral, but unique function on a peripheral, but
@ -195,7 +195,7 @@ character.
Carriage return, line feed, form Carriage return, line feed, form
feed, and bell are all control feed, and bell are all control
characters. characters.
.pp
CONTROLLER CARD]>A hardware circuit CONTROLLER CARD]>A hardware circuit
board which is plugged into an APPLE board which is plugged into an APPLE
connector which allows communication connector which allows communication
@ -203,11 +203,11 @@ with a peripheral device, such as a
disk or printer. A controller card disk or printer. A controller card
usually contains a small driver usually contains a small driver
program in ROM. program in ROM.
.PP
CSWL]>A vector in zero-page through CSWL]>A vector in zero-page through
which output data is passed for which output data is passed for
display on the CRT or for printing. display on the CRT or for printing.
.pp
CYCLE]>The smallest unit of time CYCLE]>The smallest unit of time
within the central processor of the within the central processor of the
computer. Each machine language computer. Each machine language
@ -215,9 +215,9 @@ instruction requires two or more
cycles to complete. One cycle (on cycles to complete. One cycle (on
the APPLE) is one micro-second or one the APPLE) is one micro-second or one
millionth of a second. millionth of a second.
.pp
DATA]>Units of information. DATA]>Units of information.
.pp
DATA SECTOR BUFFER]>On the APPLE, a DATA SECTOR BUFFER]>On the APPLE, a
256 byte buffer used by DOS to hold 256 byte buffer used by DOS to hold
the image of any given sector on the the image of any given sector on the
@ -226,29 +226,29 @@ from the file, data is extracted from
the data sector buffer until it is the data sector buffer until it is
exhausted, at which time it is exhausted, at which time it is
refilled with the next sector image. refilled with the next sector image.
.pp
DATA TYPE]>The type of information DATA TYPE]>The type of information
stored in a byte. A byte might stored in a byte. A byte might
contain a printable ASCII character, binary contain a printable ASCII character, binary
numeric data, or a machine language numeric data, or a machine language
instruction. instruction.
.pp
DCT]>Device Characteristics Table. DCT]>Device Characteristics Table.
Used as an input parameter table to Used as an input parameter table to
Read/Write Track/Sector (RWTS) to Read/Write Track/Sector (RWTS) to
describe the hardware characteristics describe the hardware characteristics
of the diskette drive. of the diskette drive.
.pp
DECIMAL]>A number system based upon DECIMAL]>A number system based upon
powers of 10. Digits range from 0 to powers of 10. Digits range from 0 to
9. 9.
.pp
DEFERRED COMMANDS]>DOS commands which DEFERRED COMMANDS]>DOS commands which
may (or must) be invoked from within may (or must) be invoked from within
an executing BASIC program. OPEN, an executing BASIC program. OPEN,
READ, WRITE, and CLOSE are all READ, WRITE, and CLOSE are all
examples of deferred commands. examples of deferred commands.
.pp
DIGITAL]>As opposed to analog. DIGITAL]>As opposed to analog.
Discrete values as opposed to Discrete values as opposed to
continuous ones. Only digital values continuous ones. Only digital values
@ -259,7 +259,7 @@ light outside, must be converted into
a numerical value which, of a numerical value which, of
necessity, must be "rounded off" to a necessity, must be "rounded off" to a
discrete value. discrete value.
.pp
DIRECT ACCESS]>Peripheral storage DIRECT ACCESS]>Peripheral storage
allowing rapid access of any piece of allowing rapid access of any piece of
data, regardless of its placement on data, regardless of its placement on
@ -270,14 +270,14 @@ read to locate the last byte. A
diskette is direct access, since the diskette is direct access, since the
arm may be rapidly moved to any arm may be rapidly moved to any
track and sector. track and sector.
.pp
DIRECTORY]>A catalog of all files DIRECTORY]>A catalog of all files
stored on a diskette. The directory stored on a diskette. The directory
must contain each file's name and its must contain each file's name and its
location on the disk as well as other location on the disk as well as other
information regarding the type of information regarding the type of
data stored there. data stored there.
.pp
DISK INITIALIZATION]>The process DISK INITIALIZATION]>The process
which places track formatting which places track formatting
information, including sectors and information, including sectors and
@ -286,7 +286,7 @@ During disk initialization, DOS also
places a VTOC and directory on the places a VTOC and directory on the
newly formatted disk, as well as newly formatted disk, as well as
saving the HELLO program. saving the HELLO program.
.pp
DISPLACEMENT]>The distance from the DISPLACEMENT]>The distance from the
beginning of a block of data to a beginning of a block of data to a
particular byte or field. particular byte or field.
@ -294,59 +294,59 @@ Displacements are usually given
beginning with 0, for the first byte, beginning with 0, for the first byte,
1 for the second, etc. Also known as 1 for the second, etc. Also known as
an offset. an offset.
.pp
DRIVER]>A program which provides an DRIVER]>A program which provides an
input stream to another program or an input stream to another program or an
output device. A printer driver output device. A printer driver
accepts input from a user program in accepts input from a user program in
the form of lines to be printed, and the form of lines to be printed, and
sends them to the printer. sends them to the printer.
.pp
DUMP]>An unformatted or partially DUMP]>An unformatted or partially
formatted listing of the contents of formatted listing of the contents of
memory or a diskette in hexadecimal. memory or a diskette in hexadecimal.
Used for diagnostic purposes. Used for diagnostic purposes.
.pp
ENCODE]>To translate data from one ENCODE]>To translate data from one
form to another for any of a number form to another for any of a number
of reasons. In DOS 3.3, of reasons. In DOS 3.3,
Data is encoded from 8 Data is encoded from 8
bit bytes to 6 bit bytes for storage bit bytes to 6 bit bytes for storage
on a DISK II. on a DISK II.
.pp
ENTRY POINT (EPA)]>The entry point ENTRY POINT (EPA)]>The entry point
address is the location within a address is the location within a
program where execution is to start. program where execution is to start.
This is not necessarily the same as This is not necessarily the same as
the load point (or lowest memory the load point (or lowest memory
address in the program). address in the program).
.pp
EOF]>End Of File. This mark signals EOF]>End Of File. This mark signals
the end of a data file. $00 for the end of a data file. $00 for
APPLE DOS text files. APPLE DOS text files.
.pp
EPILOGUE]>The last three bytes of a EPILOGUE]>The last three bytes of a
field on a track. These unique bytes field on a track. These unique bytes
are used to insure the integrity of are used to insure the integrity of
the data which preceeds them. the data which preceeds them.
.pp
EXCLUSIVE OR]>A logical operation EXCLUSIVE OR]>A logical operation
which compares two bits to determine which compares two bits to determine
if they are different. 1 EOR 0 if they are different. 1 EOR 0
results in 1. 1 EOR 1 results in 0. results in 1. 1 EOR 1 results in 0.
.pp
FIELD]>A group of contiguous bytes FIELD]>A group of contiguous bytes
forming a single piece of data, such forming a single piece of data, such
as a person's name, his age, or his as a person's name, his age, or his
social security number. In disk social security number. In disk
formatting, a group of data bytes formatting, a group of data bytes
surrounded by gaps. surrounded by gaps.
.pp
FILE]>A named collection of data on a FILE]>A named collection of data on a
diskette or other mass storage diskette or other mass storage
medium. Files can contain data or medium. Files can contain data or
programs. programs.
.pp
FILE BUFFERS]>In APPLE DOS, a FILE BUFFERS]>In APPLE DOS, a
collection of buffers used to manage collection of buffers used to manage
one open file. Included are a data one open file. Included are a data
@ -356,51 +356,51 @@ workarea buffer, the name of the
file, and pointers. The DOS command, file, and pointers. The DOS command,
MAXFILES 3, causes 3 of these file MAXFILES 3, causes 3 of these file
buffers to be allocated. buffers to be allocated.
.pp
FILE DESCRIPTOR]>A single entry in a FILE DESCRIPTOR]>A single entry in a
diskette directory which describes diskette directory which describes
one file. Included are the name of one file. Included are the name of
the file, its data type, its length, the file, its data type, its length,
and its location on the diskette. and its location on the diskette.
.pp
FILE MANAGER]>That portion of DOS FILE MANAGER]>That portion of DOS
which manages files. The file which manages files. The file
manager handles such general manager handles such general
operations as OPEN, CLOSE, READ, operations as OPEN, CLOSE, READ,
WRITE, POSITION, RENAME, DELETE, etc. WRITE, POSITION, RENAME, DELETE, etc.
.pp
FILE TYPE]>The type of data held by a FILE TYPE]>The type of data held by a
file. Valid DOS file types are file. Valid DOS file types are
Binary, Applesoft, Integer-BASIC, Binary, Applesoft, Integer-BASIC,
Text, Relocatable, S, A, and B. Text, Relocatable, S, A, and B.
.pp
FIRMWARE]>A middle ground between FIRMWARE]>A middle ground between
hardware and software. Usually used hardware and software. Usually used
to describe micro-code or programs to describe micro-code or programs
which have been stored in read-only which have been stored in read-only
memory. memory.
.pp
GAPS]>The spaces between fields of GAPS]>The spaces between fields of
data on a diskette. Gaps on an APPLE data on a diskette. Gaps on an APPLE
diskette contain self-sync bytes. diskette contain self-sync bytes.
.pp
HARD ERROR]>An unrecoverable HARD ERROR]>An unrecoverable
Input/Output error. The data stored Input/Output error. The data stored
in the disk sector can never be in the disk sector can never be
successfully read again. successfully read again.
.pp
HARDWARE]>Physical computer HARDWARE]>Physical computer
equipment, as opposed to programs equipment, as opposed to programs
which run on the equipment. which run on the equipment.
A disk drive is an example of a A disk drive is an example of a
hardware component. hardware component.
.pp
HEAD]>The read/write head on a HEAD]>The read/write head on a
diskette drive. A magnetic pickup, diskette drive. A magnetic pickup,
similar in nature to the head on a similar in nature to the head on a
stereo tapedeck, which rests on the stereo tapedeck, which rests on the
spinning surface of the diskette. spinning surface of the diskette.
.pp
HEXADECIMAL/HEX]>A numeric system HEXADECIMAL/HEX]>A numeric system
based on powers of 16. Valid hex based on powers of 16. Valid hex
digits range from 0 to 9 and A to F, digits range from 0 to 9 and A to F,
@ -412,39 +412,39 @@ represent the contents of one byte.
Hexadecimal is used with computers Hexadecimal is used with computers
because it easily converts with because it easily converts with
binary. binary.
.pp
HIGH MEMORY]>Those memory locations HIGH MEMORY]>Those memory locations
which have high address values. which have high address values.
$FFFF is the highest memory location. $FFFF is the highest memory location.
Also called the "top" of memory. Also called the "top" of memory.
.pp
HIMEM]>APPLE's zero-page address HIMEM]>APPLE's zero-page address
which identifies the first byte past which identifies the first byte past
the available memory which can be the available memory which can be
used to store BASIC programs and used to store BASIC programs and
their variables. their variables.
.pp
IMMEDIATE COMMAND]>A DOS command IMMEDIATE COMMAND]>A DOS command
which may be entered at any time, which may be entered at any time,
especially when DOS is waiting for a especially when DOS is waiting for a
command from the keyboard. Deferred command from the keyboard. Deferred
commands are the opposite of commands are the opposite of
immediate commands. immediate commands.
.pp
INDEX]>A displacement into a table or INDEX]>A displacement into a table or
block of storage. block of storage.
.pp
INSTRUCTION]>A single step to be INSTRUCTION]>A single step to be
performed in an assembly language or performed in an assembly language or
machine language program. machine language program.
Instructions perform such operations Instructions perform such operations
as addition, subtraction, store, or as addition, subtraction, store, or
load. load.
.pp
INTEGER]>As opposed to floating INTEGER]>As opposed to floating
point. A "whole" number with no point. A "whole" number with no
fraction associated with it. fraction associated with it.
.pp
INTERCEPT]>A program which logically INTERCEPT]>A program which logically
places itself in the execution path places itself in the execution path
of another program, or pair of of another program, or pair of
@ -452,13 +452,13 @@ programs. A video intercept
is used to re-direct program output is used to re-direct program output
from the screen to a printer, from the screen to a printer,
for example. for example.
.pp
INTERLEAVE]>The practice of selecting INTERLEAVE]>The practice of selecting
the order of sectors on a diskette the order of sectors on a diskette
track to minimize access time due to track to minimize access time due to
rotational delay. Also called rotational delay. Also called
"skewing" or interlacing. "skewing" or interlacing.
.pp
INTERRUPT]>A hardware signal which INTERRUPT]>A hardware signal which
causes the computer to halt execution causes the computer to halt execution
of a program and enter a special of a program and enter a special
@ -466,103 +466,103 @@ handler routine. Interrupts are used
to service real-time clock to service real-time clock
time-outs, BRK instructions, and time-outs, BRK instructions, and
RESET. RESET.
.pp
IOB]>Input/Output Block. A IOB]>Input/Output Block. A
collection of parameter data, passed collection of parameter data, passed
to Read/Write Track/Sector, to Read/Write Track/Sector,
describing the operation to be describing the operation to be
performed. performed.
.pp
I/O ERROR]>Input/Output Error. I/O ERROR]>Input/Output Error.
An error which occurs An error which occurs
during transmission of data to or during transmission of data to or
from a peripheral device, such as a from a peripheral device, such as a
disk or cassette tape. disk or cassette tape.
.pp
JMP]>A 6502 assembly langauge JMP]>A 6502 assembly langauge
instruction which causes the computer instruction which causes the computer
to begin executing instructions at a to begin executing instructions at a
different location in memory. different location in memory.
Similar to a GOTO statement in BASIC. Similar to a GOTO statement in BASIC.
.pp
JSR]>A 6502 assembly langauge JSR]>A 6502 assembly langauge
instruction which causes the computer instruction which causes the computer
to "call" a subroutine. Similar to a to "call" a subroutine. Similar to a
CALL statement in BASIC. CALL statement in BASIC.
.pp
K]>A unit of measurement, usually K]>A unit of measurement, usually
applied to bytes. 1 K bytes is applied to bytes. 1 K bytes is
equivalent to 1024 bytes. equivalent to 1024 bytes.
.PP
KSWL]>A vector in zero-page through KSWL]>A vector in zero-page through
which input data is passed for which input data is passed for
from the keyboard or a remote from the keyboard or a remote
terminal. terminal.
.pp
LABEL]>A name associated with a LABEL]>A name associated with a
location in a program or in memory. location in a program or in memory.
Labels are used in assembly langauge Labels are used in assembly langauge
much like statement numbers are used much like statement numbers are used
in BASIC. in BASIC.
.PP
LATCH]>A component into which the LATCH]>A component into which the
Input/Output Input/Output
hardware can store a byte value, hardware can store a byte value,
which will hold that value until the which will hold that value until the
central processor has time to read central processor has time to read
it (or vice versa). it (or vice versa).
.pp
LINK]>An address pointer in an LINK]>An address pointer in an
element of a linked chain of data or element of a linked chain of data or
buffers. buffers.
.pp
LIST]>A one dimensional sequential LIST]>A one dimensional sequential
array of data items. array of data items.
.pp
LOAD POINT (LP)]>The lowest address LOAD POINT (LP)]>The lowest address
of a loaded assembly language of a loaded assembly language
program -- the first byte loaded. program -- the first byte loaded.
Not necessarily the same as the entry Not necessarily the same as the entry
point address (EPA). point address (EPA).
.pp
LOGICAL]>A form of arithmetic which LOGICAL]>A form of arithmetic which
operates with binary "truth" or operates with binary "truth" or
"false", 1 or 0. AND, OR, NAND, NOR, "false", 1 or 0. AND, OR, NAND, NOR,
and EXCLUSIVE OR are all logical and EXCLUSIVE OR are all logical
operations. operations.
.pp
LOOP]>A programming construction in LOOP]>A programming construction in
which a which a
group of instructions or statements group of instructions or statements
are repeatedly executed. are repeatedly executed.
.pp
LOW MEMORY]>The memory locations with LOW MEMORY]>The memory locations with
the lowest addresses. $0000 is the the lowest addresses. $0000 is the
lowest memory location. Also called lowest memory location. Also called
the "bottom" of memory. the "bottom" of memory.
.pp
LOMEM]>APPLE's zero-page address LOMEM]>APPLE's zero-page address
which identifies the first byte of which identifies the first byte of
the available memory which can be the available memory which can be
used to store BASIC programs and used to store BASIC programs and
their variables. their variables.
.pp
LSB/LO ORDER]>Least Significant Bit LSB/LO ORDER]>Least Significant Bit
or Least Significant Byte. The 1's or Least Significant Byte. The 1's
bit in a byte or the second pair of bit in a byte or the second pair of
hexadecimal digits forming an hexadecimal digits forming an
address. In the address $8030, $30 address. In the address $8030, $30
is the LO order part of the address. is the LO order part of the address.
.pp
MASTER DISK]>A DOS diskette which MASTER DISK]>A DOS diskette which
will boot in an APPLE II of any size will boot in an APPLE II of any size
memory and take full advantage of it. memory and take full advantage of it.
.pp
MICROSECOND]>A millionth of a MICROSECOND]>A millionth of a
second. Equivalent to one cycle of second. Equivalent to one cycle of
the APPLE II central processor. the APPLE II central processor.
Also written as "Usec". Also written as "Usec".
.pp
MONITOR]>A machine language program MONITOR]>A machine language program
which always resides in the computer which always resides in the computer
and which is the first to receive and which is the first to receive
@ -571,35 +571,35 @@ up. The APPLE monitor resides in ROM
and allows examination and and allows examination and
modification of memory at a byte modification of memory at a byte
level. level.
.pp
MSB/HI ORDER]>Most Significant Bit or MSB/HI ORDER]>Most Significant Bit or
Most Significant Byte. The 128's bit Most Significant Byte. The 128's bit
of a byte (the left-most) or the of a byte (the left-most) or the
first pair of hexadecimal digits in first pair of hexadecimal digits in
an address. In the byte value $83, an address. In the byte value $83,
the MSB is on (is a 1). the MSB is on (is a 1).
.pp
NULL]>Empty, having no length or NULL]>Empty, having no length or
value. A null string is one which value. A null string is one which
contains no characters. The null contains no characters. The null
control character ($00) produces no control character ($00) produces no
effect on a printer (also called an effect on a printer (also called an
idle). idle).
.pp
NIBBLE/NYBBLE]>A portion of a byte, NIBBLE/NYBBLE]>A portion of a byte,
usually 4 bits and represented by a usually 4 bits and represented by a
single hexadecimal digit. $FE single hexadecimal digit. $FE
contains two nibbles, $F and $E. contains two nibbles, $F and $E.
.pp
OBJECT CODE]>A machine language OBJECT CODE]>A machine language
program in binary form, ready to program in binary form, ready to
execute. Object code is the output execute. Object code is the output
of an assembler. of an assembler.
.pp
OBJECT MODULE]>A complete machine OBJECT MODULE]>A complete machine
language program in object code form, language program in object code form,
stored as a file on a diskette. stored as a file on a diskette.
.pp
OFFSET]>The distance from the OFFSET]>The distance from the
beginning of a block of data to a beginning of a block of data to a
particular byte or field. particular byte or field.
@ -607,26 +607,26 @@ Offsets are usually given
beginning with 0, for the first byte, beginning with 0, for the first byte,
1 for the second, etc. Also known as 1 for the second, etc. Also known as
a displacement. a displacement.
.pp
OPCODE]>Operation Code. The three OPCODE]>Operation Code. The three
letter mnemonic representing a single letter mnemonic representing a single
assembly langauge instruction. JMP assembly langauge instruction. JMP
is the opcode for the jump is the opcode for the jump
instruction. instruction.
.pp
OPERATING SYSTEM]>A machine language OPERATING SYSTEM]>A machine language
program which manages the memory and program which manages the memory and
peripherals automatically, peripherals automatically,
simplifying the job of the simplifying the job of the
applications programmer. applications programmer.
.pp
OR]>The logical operation comparing OR]>The logical operation comparing
two bits to determine if either of two bits to determine if either of
them are 1. 1 OR 1 results in 1 them are 1. 1 OR 1 results in 1
(true), 1 (true), 1
OR 0 results in 1, 0 OR 0 results in OR 0 results in 1, 0 OR 0 results in
0 (false). 0 (false).
.pp
OVERHEAD]>The space required by the OVERHEAD]>The space required by the
system, either in memory or on the system, either in memory or on the
disk, to manage either. The disk disk, to manage either. The disk
@ -634,4 +634,3 @@ directory and VTOC are part of a
diskette's overhead. diskette's overhead.
.br .br
.nx appendix c.2 .nx appendix c.2
\x00

113
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@ -1,21 +1,21 @@
.pp
PAGE]>256 bytes of memory which share PAGE]>256 bytes of memory which share
a common high order address byte. a common high order address byte.
Zero page is the first 256 bytes of Zero page is the first 256 bytes of
memory ($0000 through $00FF). memory ($0000 through $00FF).
.pp
PARALLEL]>Opposite of serial. A PARALLEL]>Opposite of serial. A
communication mode which sends all of communication mode which sends all of
the bits in a byte at once, each over the bits in a byte at once, each over
a separate line or wire. a separate line or wire.
.pp
PARAMETER LIST]>An area of storage PARAMETER LIST]>An area of storage
set aside for communication between set aside for communication between
a calling program and a subroutine. a calling program and a subroutine.
The parameter list contains input and The parameter list contains input and
output variables which will be used output variables which will be used
by the subroutine. by the subroutine.
.pp
PARITY]>A scheme, similar to PARITY]>A scheme, similar to
checksums but on a bit level rather checksums but on a bit level rather
than a byte level, which allows than a byte level, which allows
@ -27,54 +27,54 @@ used in expensive memory to detect or
correct single bit failures, and when correct single bit failures, and when
sending data over communications sending data over communications
lines to detect noise errors. lines to detect noise errors.
.pp
PARSE]>The process of interpreting PARSE]>The process of interpreting
character string data, such as a character string data, such as a
command with keywords. command with keywords.
.pp
PATCH]>A small change to the object PATCH]>A small change to the object
code of an assembly language program. code of an assembly language program.
Also called a "zap". Also called a "zap".
.pp
PERIPHERAL]>A device which is PERIPHERAL]>A device which is
external to the computer itself, such external to the computer itself, such
as a disk drive or a printer. Also as a disk drive or a printer. Also
called an Input/Output device. called an Input/Output device.
.pp
PHYSICAL RECORD]>A collection of data PHYSICAL RECORD]>A collection of data
corresponding to the smallest unit of corresponding to the smallest unit of
storage on a peripheral device. storage on a peripheral device.
For disks, a physical record For disks, a physical record
is a sector. is a sector.
.pp
POINTER]>The address or memory POINTER]>The address or memory
location of a block of data or a location of a block of data or a
single data item. The address single data item. The address
"points" to the data. "points" to the data.
.pp
PROLOGUE]>The three bytes at the PROLOGUE]>The three bytes at the
beginning of a disk field which beginning of a disk field which
uniquely identify it from any other uniquely identify it from any other
data on the track. data on the track.
.pp
PROM]>Programmable Read Only Memory. PROM]>Programmable Read Only Memory.
PROMs are usually used on controller PROMs are usually used on controller
cards associated with peripherals to cards associated with peripherals to
hold the driver program which hold the driver program which
interfaces the device to applications interfaces the device to applications
programs. programs.
.pp
PROMPT]>An output string which lets PROMPT]>An output string which lets
the user know that input is expected. the user know that input is expected.
A "*" is the prompt character for the A "*" is the prompt character for the
APPLE monitor. APPLE monitor.
.pp
PROTECTED DISK]>A diskette whose PROTECTED DISK]>A diskette whose
format or content has been modified format or content has been modified
to prevent its being copied. Most to prevent its being copied. Most
retail software today is distributed retail software today is distributed
on protected disks to prevent theft. on protected disks to prevent theft.
.pp
PSEUDO-OPCODE]>A special assembly PSEUDO-OPCODE]>A special assembly
language opcode which does not language opcode which does not
translate into a machine instruction. translate into a machine instruction.
@ -83,17 +83,17 @@ assembler to perform some function,
such as skipping a page in an such as skipping a page in an
assembly listing or reserving data assembly listing or reserving data
space in the output object code. space in the output object code.
.pp
RANDOM ACCESS]>Direct access. The RANDOM ACCESS]>Direct access. The
capability to rapidly access any capability to rapidly access any
single piece of data on a storage single piece of data on a storage
medium without having to sequentially medium without having to sequentially
read all of its predecessors. read all of its predecessors.
.pp
RAM]>Random Access Memory. Computer RAM]>Random Access Memory. Computer
memory which will allow storage and memory which will allow storage and
retrieval of values by address. retrieval of values by address.
.pp
RECAL]>Recalibrate the disk arm so RECAL]>Recalibrate the disk arm so
that the read/write head is that the read/write head is
positioned over track zero. This is positioned over track zero. This is
@ -101,13 +101,13 @@ done by pulling the arm as far as it
will go to the outside of the will go to the outside of the
diskette until it hits a stop, diskette until it hits a stop,
producing a "clacking" sound. producing a "clacking" sound.
.pp
RECORD]>A collection of associated RECORD]>A collection of associated
data items or fields. One or more data items or fields. One or more
records are usually associated with a records are usually associated with a
file. Each record might correspond file. Each record might correspond
to an employee, for example. to an employee, for example.
.pp
REGISTER]>A named temporary storage REGISTER]>A named temporary storage
location in the central processor location in the central processor
itself. The 6502 has 5 registers; itself. The 6502 has 5 registers;
@ -115,18 +115,18 @@ the A, X, Y, S, and P registers.
Registers are used by an assembly Registers are used by an assembly
language program to access memory and language program to access memory and
perform arithmetic. perform arithmetic.
.pp
RELEASE]>A version of a distributed RELEASE]>A version of a distributed
piece of software. There have been piece of software. There have been
several releases of DOS. several releases of DOS.
.pp
RELOCATABLE]>The attribute of RELOCATABLE]>The attribute of
an object module file an object module file
which contains a machine language which contains a machine language
program and the information necessary program and the information necessary
to make it run at any memory to make it run at any memory
location. location.
.pp
RETURN CODE]>A numeric value returned RETURN CODE]>A numeric value returned
from a subroutine, indicating the from a subroutine, indicating the
success or failure of the operation success or failure of the operation
@ -135,74 +135,74 @@ usually means there were no errors.
Any other value indicates the nature Any other value indicates the nature
of the error, as defined by the of the error, as defined by the
design of the subroutine. design of the subroutine.
.PP
ROM]>Read Only Memory. Memory which ROM]>Read Only Memory. Memory which
has a permanent value. The APPLE has a permanent value. The APPLE
monitor and BASIC interpreters are monitor and BASIC interpreters are
stored in ROM. stored in ROM.
.PP
RWTS]>Read/Write Track/Sector. A RWTS]>Read/Write Track/Sector. A
collection of subroutines which allow collection of subroutines which allow
access to the diskette at a access to the diskette at a
track and sector level. RWTS is track and sector level. RWTS is
part of DOS and may be called by part of DOS and may be called by
external assembly language programs. external assembly language programs.
.pp
SEARCH]>The process of scanning a SEARCH]>The process of scanning a
track for a given sector. track for a given sector.
.PP
SECTOR]>The smallest updatable unit SECTOR]>The smallest updatable unit
of data on a disk track. One sector of data on a disk track. One sector
on an APPLE DISK II contains 256 on an APPLE DISK II contains 256
data bytes. data bytes.
.pp
SECTOR ADDRESS]>A disk field which SECTOR ADDRESS]>A disk field which
identifies the sector data field which identifies the sector data field which
follows in terms of its volume, follows in terms of its volume,
track, and sector number. track, and sector number.
.pp
SECTOR DATA]>A disk field which SECTOR DATA]>A disk field which
contains the actual sector data in contains the actual sector data in
nibbilized form. nibbilized form.
.pp
SEEK]>The process of moving the disk SEEK]>The process of moving the disk
arm to a given track. arm to a given track.
.pp
SELF-SYNC]>Also called "auto-sync" SELF-SYNC]>Also called "auto-sync"
bytes. Special disk bytes which bytes. Special disk bytes which
contain more than 8 bits, allowing contain more than 8 bits, allowing
synchronization of the hardware to synchronization of the hardware to
byte boundaries when reading. byte boundaries when reading.
.pp
SEQUENTIAL ACCESS]>A mode of data SEQUENTIAL ACCESS]>A mode of data
retreival where each byte of data is retreival where each byte of data is
read in the order in which it was read in the order in which it was
written to the disk. written to the disk.
.pp
SERIAL]>As opposed to parallel. A SERIAL]>As opposed to parallel. A
communication mode which sends data communication mode which sends data
bits one at a time over a single line bits one at a time over a single line
or wire. or wire.
.pp
SHIFT]>A logical operation which SHIFT]>A logical operation which
moves the bits of a byte either left moves the bits of a byte either left
or right one position, moving a 0 or right one position, moving a 0
into the bit at the other end. into the bit at the other end.
.pp
SLAVE DISK]>A diskette with a copy of SLAVE DISK]>A diskette with a copy of
DOS which is not relocatable. The DOS which is not relocatable. The
DOS image will always be loaded into DOS image will always be loaded into
the same memory location, regadless the same memory location, regadless
of the size of the machine. of the size of the machine.
.pp
SOFT ERROR]>A recoverable I/O error. SOFT ERROR]>A recoverable I/O error.
A worn diskette might produce soft A worn diskette might produce soft
errors occasionally. errors occasionally.
.pp
SOFTWARE]>Computer programs and data SOFTWARE]>Computer programs and data
which can be loaded into RAM memory which can be loaded into RAM memory
and executed. and executed.
.pp
SOURCE CODE]>A program in a form SOURCE CODE]>A program in a form
which is understandable to humans; which is understandable to humans;
in character form as opposed in character form as opposed
@ -211,10 +211,10 @@ Source assembly code must be
processed by an assembler to processed by an assembler to
translate it into machine or "object" translate it into machine or "object"
code. code.
.pp
SKEWING]>The process of interleaving SKEWING]>The process of interleaving
sectors. See INTERLEAVE. sectors. See INTERLEAVE.
.pp
STATE MACHINE]>A process (in software STATE MACHINE]>A process (in software
or hardware) which defines a or hardware) which defines a
unique target state, given an input unique target state, given an input
@ -223,18 +223,18 @@ state machine approach is used in DOS
to keep track of its video intercepts to keep track of its video intercepts
and by the hardware on the disk and by the hardware on the disk
controller card to process disk data. controller card to process disk data.
.pp
STROBE]>The act of triggering an I/O STROBE]>The act of triggering an I/O
function by momentarily referencing a function by momentarily referencing a
special I/O address. Strobing $C030 special I/O address. Strobing $C030
produces a click on the speaker. produces a click on the speaker.
Also called "toggling". Also called "toggling".
.pp
SUBROUTINE]>A program whose function SUBROUTINE]>A program whose function
is required repeatedly during is required repeatedly during
execution, and therefore is called by execution, and therefore is called by
a main program in several places. a main program in several places.
.pp
TABLE]>A collection of data entries, TABLE]>A collection of data entries,
having similar format, residing in having similar format, residing in
memory. Each entry might contain the memory. Each entry might contain the
@ -242,13 +242,13 @@ name of a program and its address,
for example. A "lookup" can be for example. A "lookup" can be
performed on such a table to locate performed on such a table to locate
any given program by name. any given program by name.
.pp
TOGGLE]>The act of triggering an I/O TOGGLE]>The act of triggering an I/O
function by momentarily referencing a function by momentarily referencing a
special I/O address. Toggling $C030 special I/O address. Toggling $C030
produces a click on the speaker. produces a click on the speaker.
Also called "strobe". Also called "strobe".
.pp
TOKENS]>A method where human TOKENS]>A method where human
recognizable words may be coded to recognizable words may be coded to
single binary byte values for memory single binary byte values for memory
@ -256,68 +256,68 @@ compression and faster processing.
BASIC statements are tokenized, where BASIC statements are tokenized, where
hex codes are assigned to words like hex codes are assigned to words like
IF, PRINT, and END. IF, PRINT, and END.
.pp
TRACK]>One complete circular path of TRACK]>One complete circular path of
magnetic storage on a diskette. magnetic storage on a diskette.
There are 35 concentric tracks on an APPLE There are 35 concentric tracks on an APPLE
diskette. diskette.
.pp
TRANSLATE TABLE]>A table of single TRANSLATE TABLE]>A table of single
byte codes which are to replace byte codes which are to replace
input codes on a one-for-one input codes on a one-for-one
basis. A translate table is used to basis. A translate table is used to
convert from 6 bit codes to disk convert from 6 bit codes to disk
codes. codes.
.PP
T/S LIST]>Track/Sector List. A T/S LIST]>Track/Sector List. A
sector which describes the location sector which describes the location
of a file by listing the track and of a file by listing the track and
sector number for each of its data sector number for each of its data
sectors in the order that they are to sectors in the order that they are to
be read or written. be read or written.
.pp
TTL]>Transistor to Transistor Logic. TTL]>Transistor to Transistor Logic.
A standard for the interconnection of A standard for the interconnection of
integrated circuits which also integrated circuits which also
defines the which voltages defines the which voltages
represent 0's and 1's. represent 0's and 1's.
.pp
UTILITY]>A program which is used to UTILITY]>A program which is used to
maintain, or assist in the development maintain, or assist in the development
of, other programs or disk files. of, other programs or disk files.
.pp
VECTOR]>A collection of pointers or VECTOR]>A collection of pointers or
JMP instructions at a fixed location JMP instructions at a fixed location
in memory which allow access to a in memory which allow access to a
relocatable program or data. relocatable program or data.
.pp
VOLUME]>An identification for a VOLUME]>An identification for a
diskette, disk platter, or cassette, diskette, disk platter, or cassette,
containing one or more files. containing one or more files.
.pp
VTOC]>Volume Table Of Contents. VTOC]>Volume Table Of Contents.
Based upon the IBM OS/VS VTOC. On Based upon the IBM OS/VS VTOC. On
the APPLE, a sector mapping the the APPLE, a sector mapping the
free sectors on the diskette and free sectors on the diskette and
giving the location of the directory. giving the location of the directory.
.pp
WARMSTART]>A restart of a program WARMSTART]>A restart of a program
which retains, as much as is which retains, as much as is
possible, the work which was in possible, the work which was in
progress at the time. A DOS progress at the time. A DOS
warmstart retains the BASIC program warmstart retains the BASIC program
in memory. in memory.
.PP
WRITE PROTECTED]>A diskette whose WRITE PROTECTED]>A diskette whose
write protect notch is covered, write protect notch is covered,
preventing the disk drive from preventing the disk drive from
writing on it. writing on it.
.pp
ZAP]>From the IBM utility program, ZAP]>From the IBM utility program,
SUPERZAP. A program which allows SUPERZAP. A program which allows
updates to a disk at a byte level, updates to a disk at a byte level,
using hexadecimal. using hexadecimal.
.pp
ZERO PAGE]>The first 256 bytes of ZERO PAGE]>The first 256 bytes of
memory in a 6502 based machine. Zero memory in a 6502 based machine. Zero
page locations have special page locations have special
@ -325,4 +325,3 @@ significance to the central
processor, making their management processor, making their management
and assignment critical. and assignment critical.
.br .br
\x00

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@ -130,4 +130,3 @@ A-20
.nf .nf
800G (Run the COPY program) 800G (Run the COPY program)
.br .br
\x00

1
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View File

@ -33,4 +33,3 @@ utilities called BENEATH APPLE DOS'
BAG OF TRICKS. See the page facing BAG OF TRICKS. See the page facing
1-1 for more details. 1-1 for more details.
.br .br
\x00

1
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@ -123,4 +123,3 @@ C-15
.sp1 .sp1
the voltages which represent 0's and the voltages which represent 0's and
.br .br
\x00