diff --git a/ch02.txt b/ch02.txt index 2795de7..f919f4d 100644 --- a/ch02.txt +++ b/ch02.txt @@ -1,248 +1,130 @@ -.bp -.np -.ce -CHAPTER 2 - THE EVOLUTION OF DOS -.sp2 +## CHAPTER 2 - THE EVOLUTION OF DOS + +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. -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 -.br DOS 3.1 - 20 July 1978 -The first release of DOS was -apparently a victim of a rush at -Apple to introduce the DISK II. As -such, it had a number of bugs. With the -movement towards the APPLE II PLUS -and the introduction of the AUTOSTART -ROM, a new release was needed. -.sp1 +The first release of DOS was apparently a victim of a rush at Apple to introduce +the DISK II. As such, it had a number of bugs. With the movement towards the +APPLE II PLUS and the introduction of the AUTOSTART ROM, a new release was +needed. + DOS 3.2 - 16 February 1979 -Although DOS 3.2 embodied more -changes from its -predecessor than any other release of -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 +Although DOS 3.2 embodied more changes from its predecessor than any other +release of 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: -- NOMON C,I,O is the initial default -under DOS 3.2. MON C,I,O was the -default under DOS 3.1. +- NOMON C,I,O is the initial default under DOS 3.2. MON C,I,O was the default + under DOS 3.1. -- Input prompts (>,],*) are echoed -when MON O is in effect, not under -MON I as was the case under 3.1. +- Input prompts (>,],*) are echoed when MON O is in effect, not under MON I as + was the case under 3.1. -- When a DOS command was entered from -the keyboard, DOS executed it and -then passed a blank followed by a -carriage return to BASIC under 3.1. Under 3.2 -only a carriage return is passed. +- When a DOS command was entered from the keyboard, DOS executed it and then + passed a blank followed by a carriage return to BASIC under 3.1. Under 3.2 + only a carriage return is passed. -- Under 3.2, certain commands may not -be entered from the keyboard but may -only be used within a BASIC program -(READ, WRITE, POSITION, OPEN, -APPEND). +- Under 3.2, certain commands may not be entered from the keyboard but may only + be used within a BASIC program (READ, WRITE, POSITION, OPEN, APPEND). -- Under 3.2, when LOADing an APPLESOFT program, -DOS automatically -converts from APPLESOFT ROM format to -APPLESOFT RAM format if the RAM version of -BASIC is in use and vice versa. +- Under 3.2, when LOADing an APPLESOFT program, DOS automatically converts from + APPLESOFT ROM format to APPLESOFT RAM format if the RAM version of BASIC is in + use and vice versa. -- DOS 3.1 could not read lower case -characters from a text file; DOS 3.2 -can. +- DOS 3.1 could not read lower case characters from a text file; DOS 3.2 can. -.bp -- Some DOS commands are allowed to -create a new file, others will not. -Under DOS 3.1, any reference to a -file that didn't exist, caused it to -be created. This forced DOS 3.1 to -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. +- Some DOS commands are allowed to create a new file, others will not. Under + DOS 3.1, any reference to a file that didn't exist, caused it to be created. + This forced DOS 3.1 to 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 -required that the monitor status -register location ($48) be set to -zero before reentering DOS. Under DOS -3.2 this is no longer necessary. +- Under 3.1, exiting to the monitor required that the monitor status register + location ($48) be set to zero before reentering DOS. Under DOS 3.2 this is no + longer necessary. -- The Read/Write-Track/Sector (RWTS) -section of DOS disables interrupts -while it is executing. Under 3.1, -RWTS could be interrupted by a -peripheral while writing to a disk, -destroying the disk. +- The Read/Write-Track/Sector (RWTS) section of DOS disables interrupts while it + is executing. Under 3.1, 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 -under 3.2. +- The default for the B (byte offset) keyword is 0 under 3.2. -- DOS was reassembled for 3.2 causing most of -its interesting locations and -routines to move slightly. This -played havoc with user programs and -utilities which had DOS addresses -built into them. +- DOS was reassembled for 3.2 causing most of its interesting locations and + routines to move slightly. This played havoc with user programs and utilities + which had DOS addresses built into them. -- Additional file types (beyond -T, I, A, and B) are defined within -DOS 3.2, although no commands yet -support them. The new types are S, -R, a new A, and a new B. -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. +- Additional file types (beyond T, I, A, and B) are defined within DOS 3.2, + although no commands yet support them. The new types are S, R, a new A, and a + new B. 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 -AUTOSTART ROM. +- Support was added under 3.2 for the AUTOSTART ROM. -- All files open when a disk full -condition occurs are closed by DOS -3.2. +- All files open when a disk full 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 was essentially a -"maintenance release" of DOS 3.2. -Minor patches were made to RWTS and -the COPY program to correct a timing -problem when a dual drive copy was -done. Additional delays were added -following a switch between drives. -.bp +DOS 3.2.1 was essentially a "maintenance release" of DOS 3.2. Minor patches +were made to RWTS and the COPY program to correct a timing problem when a dual +drive copy was done. Additional delays were added following a switch between +drives. + DOS 3.3 - 25 August 1980 -Introduced in mid 1980 as a -hardware/software upgrade from DOS -3.2.1, the DOS 3.3 package includes -new bootstrap and state ROM chips for -the disk controller card which -provide the capability to -format, read, and write a -diskette with 16 sectors. -(These ROMs are the -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 -.pi-2 -.in2 -.ps0 +Introduced in mid 1980 as a hardware/software upgrade from DOS 3.2.1, the DOS +3.3 package includes new bootstrap and state ROM chips for the disk controller +card which provide the capability to format, read, and write a diskette with 16 +sectors. (These ROMs are the 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: -- The initial DOS bootstrap loader -was moved to $800 under 3.3. It was -at $300 under 3.2. In addition, as -stored on the diskette (track 0 -sector 0) it is nibbilized in the -same way as all other sectors under -3.3. +- The initial DOS bootstrap loader was moved to $800 under 3.3. It was at $300 + under 3.2. In addition, as 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 -position improperly if the file was a -multiple of 256 bytes long was fixed -under 3.3. +- A bug in APPEND which caused it to position improperly if the file was a + multiple of 256 bytes long was fixed under 3.3. -- A VERIFY command is internally -executed after every SAVE or BSAVE -under 3.3. +- A VERIFY command is internally executed after every SAVE or BSAVE under 3.3. -- All 4 bytes are used in the Volume -Table Of Contents (VTOC) free sector bit map when -keeping track of free sectors. This -allows DOS to handle up to 32 sectors -per track. Of course, RWTS will only -handle 16 sectors due to hardware -limitations. +- All 4 bytes are used in the Volume Table Of Contents (VTOC) free sector bit + map when keeping track of free sectors. This allows DOS to handle up to 32 + sectors per track. Of course, RWTS will only handle 16 sectors due to hardware + limitations. -- If a LANGUAGE CARD is present, DOS -stores a zero on it at $E000 during -bootstrap to force the HELLO program -on the master diskette to reload -BASIC. +- If a LANGUAGE CARD is present, DOS stores a zero on it at $E000 during + bootstrap to force the HELLO program on the master diskette to reload BASIC. -- DOS is read into memory from the -top down (backwards) under 3.3 rather than the -bottom up. Its image is -still stored in the same order on the -diskette (tracks 0, 1, and 2), -however. +- DOS is read into memory from the top down (backwards) under 3.3 rather than + the bottom up. Its image is still stored in the same order on the diskette + (tracks 0, 1, and 2), however. -- Additional programs added to the -master diskette under 3.3 include -FID, a generalized file utility which -allows individual files or groups of -files to be copied, MUFFIN, a -conversion copy routine to allow 3.2 -files to be moved to 16 sector 3.3 -diskettes, BOOT 13, a program which -will boot a 13 sector diskette, -and a new COPY program -which will also support single drive -copies. +- Additional programs added to the master diskette under 3.3 include FID, a + generalized file utility which allows individual files or groups of files to + be copied, MUFFIN, a conversion copy routine to allow 3.2 files to be moved to + 16 sector 3.3 diskettes, BOOT 13, a program which will boot a 13 sector + diskette, 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. -- 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