From 13 sectors to 16: DOS 3.2 and DOS 3.3

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The Disk II wrote 35 tracks on a diskette, and DOS 3.2, of February 1979, cut each track into 13 sectors of 256 bytes. In August 1980 Apple brought out DOS 3.3: a new way of encoding the bits on the diskette put 16 sectors on each track, and a diskette held 140 KB, 23 percent more. The drive stayed as it was; what changed was the ROM of the Disk II controller card, which an owner changed, or had the dealer change, with the upgrade.

Then came the diskettes already written. A controller of 16 sectors can’t read one of 13, so the System Master of DOS 3.3 brought two programs for them: BOOT13, which starts an old diskette, and MUFFIN, which moves its files to a new one. Rich Williams wrote MUFFIN at Apple, and the name was meant to stand for Move Utility For Files In NewDOS.

This page starts DOS 3.2 on an Apple ][+ with the controller of 13 sectors, then the same machine with the controller of 16 and DOS 3.3, which can’t read the old diskette, moves a program from it with MUFFIN, and starts the old diskette anyway with BOOT13.

What you need

• Apple DOS 3.2 Plus.nib, the System Master of DOS 3.2 for the Apple ][+, on the Asimov archive; a .nib keeps the 13 sectors as they are on the diskette;
• DOS 3.3 System Master - 680-0210-A (1982).dsk, the System Master of DOS 3.3, in the same folder.

./fetch-disks.sh in this repository downloads them into disks/ and checks them.

The DOS Manual of DOS 3.3 is on the Internet Archive.

The machine

An Apple ][+ with 48 KB and Applesoft in its ROM, and a Disk II controller card in slot 6 with the ROM of 13 sectors and the System Master of DOS 3.2:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/Apple2_Plus.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -s6 'diskii,sectors13,disk1="disks/Apple DOS 3.2 Plus.nib"'

The same Apple ][+ after the upgrade, its controller with the ROM of 16 sectors, the System Master of DOS 3.3 in drive 1 and the one of DOS 3.2 in drive 2:

izapple2 -model none -board 2plus -cpu 6502 -screen green \
    -rom "<internal>/Apple2_Plus.rom" \
    -charrom "<internal>/Apple2rev7CharGen.rom" -forceCaps \
    -saveDir changes \
    -s6 'diskii,disk1=disks/DOS 3.3 System Master - 680-0210-A (1982).dsk,disk2="disks/Apple DOS 3.2 Plus.nib"'

MUFFIN writes to the System Master. With -saveDir changes, izapple2 keeps what is written in the folder changes, and leaves the file of the System Master as it was downloaded; started again with the same option, the machine finds the changes there. Make the folder before starting izapple2: mkdir changes.

The model dos32 of izapple2 is a first Apple ][ with a controller of 13 sectors, a firmware card and a diskette of DOS 3.2 that izapple2 carries:

izapple2 -model dos32 -screen green

DOS 3.2

1. Start izapple2 with the first command. The Apple ][+ starts the diskette, and the System Master of DOS 3.2 greets, from June 1979. Type CATALOG.

   

   Its programs are in Applesoft, A, for the Apple ][+: Little Brick Out, a smaller Breakout, Color Demosoft, Lemonade.

DOS 3.3

1. Quit izapple2 and start it with the second command, the machine after the upgrade. DOS 3.3 starts from drive 1. Type CATALOG,D2, the diskette of DOS 3.2 in drive 2:

   

   The new controller does not find its sectors on the old diskette.

MUFFIN

1. Type BRUN MUFFIN,D1. MUFFIN is a program in machine code on the System Master, run with BRUN, binary run; ,D1 because DOS still looks at drive 2.

   

2. Choose 1, Convert files, and answer: the source in slot 6, drive 2, the old diskette; the destination in slot 6, drive 1, the new one; the file LITTLE BRICK OUT. Press Return to begin.

   

   The program is the same, its sectors laid out in the new format.

3. Press Return, choose 2 to quit, and type CATALOG,D1. The catalog stops when the screen is full; press Space for the rest.

   

   Little Brick Out is at the end, on a diskette of 16 sectors now, and RUN LITTLE BRICK OUT runs it.

BOOT13

1. Type RUN START13, the program of the System Master that runs BOOT13 and asks where to start from:

   

2. BOOT13 starts the diskette in drive 1: put the System Master of DOS 3.2 in drive 1, dropping its file on the area of drive 1 of the izapple2 window (F8 shows the areas), and press Return for slot 6.

   

   DOS 3.2 is running on the controller of 16 sectors, started by BOOT13 and not by the ROM of the card. A diskette of DOS 3.2 kept working, started this way, until its files were moved.

What next

Life with DOS 3.3 goes on with DOS 3.3, a diskette of your own initialized and written to.