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.bp ## CHAPTER 2 - THE EVOLUTION OF DOS
.np
.ce Since its introduction, Apple DOS has gone through three major versions. All of
CHAPTER 2 - THE EVOLUTION OF DOS these versions look very much the same on the surface. All commands supported
.sp2 by DOS 3.3 are also supported in 3.2 and 3.1. The need for additional versions
has been more to fix errors in DOS and to make minor enhancements than to
provide additional functionality. Only DOS 3.3 has offered any major
improvement in function; an increase in the number of sectors that will fit on a
track from 13 to 16.
Since its introduction, Apple DOS has
gone through three major versions.
All of these versions look
very much the same on the surface.
All commands supported by DOS 3.3
are also supported in 3.2 and 3.1.
The need for additional versions has
been more to fix errors in DOS and to
make minor enhancements than to
provide additional functionality.
Only DOS 3.3 has offered any major
improvement in function; an increase
in the number of sectors that will
fit on a track from 13 to 16.
.sp1
DOS 3 - 29 June 1978 DOS 3 - 29 June 1978
.br
DOS 3.1 - 20 July 1978 DOS 3.1 - 20 July 1978
The first release of DOS was The first release of DOS was apparently a victim of a rush at Apple to introduce
apparently a victim of a rush at the DISK II. As such, it had a number of bugs. With the movement towards the
Apple to introduce the DISK II. As APPLE II PLUS and the introduction of the AUTOSTART ROM, a new release was
such, it had a number of bugs. With the needed.
movement towards the APPLE II PLUS
and the introduction of the AUTOSTART
ROM, a new release was needed.
.sp1
DOS 3.2 - 16 February 1979 DOS 3.2 - 16 February 1979
Although DOS 3.2 embodied more Although DOS 3.2 embodied more changes from its predecessor than any other
changes from its release of DOS, 90% of the basic structure of DOS 3.1 was retained. The major
predecessor than any other release of differences between DOS 3.1 and 3.2 and later versions of DOS are listed below:
DOS, 90% of the basic structure of DOS 3.1
was retained. The major differences
between DOS 3.1 and 3.2 and later versions of DOS
are listed below:
.sp1
.pi-2
.in2
.ps0
- 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 default
under DOS 3.2. MON C,I,O was the under DOS 3.1.
default under DOS 3.1.
- Input prompts (>,],*) are echoed - Input prompts (>,],*) are echoed when MON O is in effect, not under MON I as
when MON O is in effect, not under was the case under 3.1.
MON I as was the case under 3.1.
- When a DOS command was entered from - When a DOS command was entered from the keyboard, DOS executed it and then
the keyboard, DOS executed it and passed a blank followed by a carriage return to BASIC under 3.1. Under 3.2
then passed a blank followed by a only a carriage return is passed.
carriage return to BASIC under 3.1. Under 3.2
only a carriage return is passed.
- Under 3.2, certain commands may not - Under 3.2, certain commands may not be entered from the keyboard but may only
be entered from the keyboard but may be used within a BASIC program (READ, WRITE, POSITION, OPEN, APPEND).
only be used within a BASIC program
(READ, WRITE, POSITION, OPEN,
APPEND).
- Under 3.2, when LOADing an APPLESOFT program, - Under 3.2, when LOADing an APPLESOFT program, DOS automatically converts from
DOS automatically APPLESOFT ROM format to APPLESOFT RAM format if the RAM version of BASIC is in
converts from APPLESOFT ROM format to use and vice versa.
APPLESOFT RAM format if the RAM version of
BASIC is in use and vice versa.
- DOS 3.1 could not read lower case - DOS 3.1 could not read lower case characters from a text file; DOS 3.2 can.
characters from a text file; DOS 3.2
can.
.bp - Some DOS commands are allowed to create a new file, others will not. Under
- Some DOS commands are allowed to DOS 3.1, any reference to a file that didn't exist, caused it to be created.
create a new file, others will not. This forced DOS 3.1 to then delete it if a new file was not desired. (LOAD XYZ
Under DOS 3.1, any reference to a under 3.1 if XYZ did not exist, created XYZ, deleted XYZ, and then printed the
file that didn't exist, caused it to file not found error message.) Under 3.2, OPEN is allowed to create a file if
be created. This forced DOS 3.1 to one does not exist, but LOAD may not.
then delete it if a new file was not
desired. (LOAD XYZ under 3.1 if XYZ
did not exist, created XYZ, deleted
XYZ, and then printed the file not
found error message.) Under 3.2, OPEN
is allowed to create a file if one
does not exist, but LOAD may not.
- Under 3.1, exiting to the monitor - Under 3.1, exiting to the monitor required that the monitor status register
required that the monitor status location ($48) be set to zero before reentering DOS. Under DOS 3.2 this is no
register location ($48) be set to longer necessary.
zero before reentering DOS. Under DOS
3.2 this is no longer necessary.
- The Read/Write-Track/Sector (RWTS) - The Read/Write-Track/Sector (RWTS) section of DOS disables interrupts while it
section of DOS disables interrupts is executing. Under 3.1, RWTS could be interrupted by a peripheral while
while it is executing. Under 3.1, writing to a disk, destroying the disk.
RWTS could be interrupted by a
peripheral while writing to a disk,
destroying the disk.
- 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.
- 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 played havoc with user programs and utilities
routines to move slightly. This which had DOS addresses built into them.
played havoc with user programs and
utilities which had DOS addresses
built into them.
- Additional file types (beyond - Additional file types (beyond T, I, A, and B) are defined within DOS 3.2,
T, I, A, and B) are defined within although no commands yet support them. The new types are S, R, a new A, and a
DOS 3.2, although no commands yet new B. R has subsequently been used by the DOS TOOLKIT for relocatable object
support them. The new types are S, module assembler files. At present, no other use is made of these extra file
R, a new A, and a new B. types.
R has subsequently been used by the
DOS TOOLKIT for relocatable object
module assembler files. At present,
no other use is made of these
extra file types.
- Support was added under 3.2 for the - Support was added under 3.2 for the AUTOSTART ROM.
AUTOSTART ROM.
- All files open when a disk full - All files open when a disk full condition occurs are closed by DOS 3.2.
condition occurs are closed by DOS
3.2. - As with each new release of DOS, several new programs were added to the master
diskette for 3.2. Among these was UPDATE 3.2, a replacement for MASTER.CREATE,
the utility for creating master diskettes. UPDATE 3.2 converts a slave into a
master and allows the HELLO file to be renamed.
- As with each new release of DOS,
several new programs were added to
the master diskette for 3.2. Among
these was UPDATE 3.2, a replacement
for MASTER.CREATE, the utility for
creating master diskettes. UPDATE
3.2 converts a slave into a master
and allows the HELLO file to be
renamed.
.br
.pi0
.in0
.ps1
.sp1
DOS 3.2.1 - 31 July 1979 DOS 3.2.1 - 31 July 1979
DOS 3.2.1 was essentially a DOS 3.2.1 was essentially a "maintenance release" of DOS 3.2. Minor patches
"maintenance release" of DOS 3.2. were made to RWTS and the COPY program to correct a timing problem when a dual
Minor patches were made to RWTS and drive copy was done. Additional delays were added following a switch between
the COPY program to correct a timing drives.
problem when a dual drive copy was
done. Additional delays were added
following a switch between drives.
.bp
DOS 3.3 - 25 August 1980 DOS 3.3 - 25 August 1980
Introduced in mid 1980 as a Introduced in mid 1980 as a hardware/software upgrade from DOS 3.2.1, the DOS
hardware/software upgrade from DOS 3.3 package includes new bootstrap and state ROM chips for the disk controller
3.2.1, the DOS 3.3 package includes card which provide the capability to format, read, and write a diskette with 16
new bootstrap and state ROM chips for sectors. (These ROMs are the same ones used with the LANGUAGE SYSTEM.) This
the disk controller card which improvement represents almost a 25% increase in available disk space over the
provide the capability to old 13 sector format. Also included in the 3.3 package is an updated version of
format, read, and write a the DOS manual, a BASICS diskette (for 13 sector boots), and a master diskette.
diskette with 16 sectors. Although the RWTS portion of DOS was almost totally rewritten, the rest of DOS
(These ROMs are the was not reassembled and only received a few patches:
same ones used with the LANGUAGE
SYSTEM.)
This improvement
represents almost a 25% increase in
available disk space over the old
13 sector format.
Also included in the 3.3
package is an updated version of the
DOS manual, a BASICS diskette (for 13
sector boots), and a master diskette.
Although the RWTS portion of DOS was
almost totally rewritten, the rest of
DOS was not reassembled and only
received a few patches:
.sp1
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.in2
.ps0
- The initial DOS bootstrap loader - The initial DOS bootstrap loader was moved to $800 under 3.3. It was at $300
was moved to $800 under 3.3. It was under 3.2. In addition, as stored on the diskette (track 0 sector 0) it is
at $300 under 3.2. In addition, as nibbilized in the same way as all other sectors under 3.3.
stored on the diskette (track 0
sector 0) it is nibbilized in the
same way as all other sectors under
3.3.
- 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 under 3.3.
multiple of 256 bytes long was fixed
under 3.3.
- A VERIFY command is internally - A VERIFY command is internally executed after every SAVE or BSAVE under 3.3.
executed after every SAVE or BSAVE
under 3.3.
- All 4 bytes are used in the Volume - All 4 bytes are used in the Volume Table Of Contents (VTOC) free sector bit
Table Of Contents (VTOC) free sector bit map when map when keeping track of free sectors. This allows DOS to handle up to 32
keeping track of free sectors. This sectors per track. Of course, RWTS will only handle 16 sectors due to hardware
allows DOS to handle up to 32 sectors limitations.
per track. Of course, RWTS will only
handle 16 sectors due to hardware
limitations.
- 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 on the master diskette to reload BASIC.
bootstrap to force the HELLO program
on the master diskette to reload
BASIC.
- DOS is read into memory from the - DOS is read into memory from the top down (backwards) under 3.3 rather than
top down (backwards) under 3.3 rather than the the bottom up. Its image is still stored in the same order on the diskette
bottom up. Its image is (tracks 0, 1, and 2), however.
still stored in the same order on the
diskette (tracks 0, 1, and 2),
however.
- Additional programs added to the - Additional programs added to the master diskette under 3.3 include FID, a
master diskette under 3.3 include generalized file utility which allows individual files or groups of files to
FID, a generalized file utility which be copied, MUFFIN, a conversion copy routine to allow 3.2 files to be moved to
allows individual files or groups of 16 sector 3.3 diskettes, BOOT 13, a program which will boot a 13 sector
files to be copied, MUFFIN, a diskette, and a new COPY program which will also support single drive copies.
conversion copy routine to allow 3.2
files to be moved to 16 sector 3.3 - Under 3.2, speed differences in some drives prevented their use together with
diskettes, BOOT 13, a program which the DOS COPY program. Because the COPY program was rewritten under 3.3, that
will boot a 13 sector diskette, restriction no longer applies.
and a new COPY program
which will also support single drive
copies.
- Under 3.2, speed differences in
some drives prevented their use
together with the DOS COPY program.
Because the COPY program was rewritten
under 3.3, that restriction no longer
applies.
.br
.pi0
.in0
.ps1
.nx ch3.1 .nx ch3.1