pyprodos 0.4.0

Python implementation of Apple ProDOS 8 file system

pyprodos

This is a simple Python implementation of the Apple ProDOS :tm: filesystem based on the technical reference manual.

It provides a simple unix-style CLI for managing existing ProDOS images in .po and .2mg files and for creating new ones. This provides an accessible file system for Apple // or other 8-bit hardware.

As an example, let's recreate a ProDOS boot volume. Grab the ProDOS 2.4.3 boot disk from https://prodos8.com/. (There's a copy in images/ here.) Check what's on it:

% prodos info images/ProDOS_2_4_3.po

Volume PRODOS.2.4.3 23-12-29T19:07
BlockDevice on images/ProDOS_2_4_3.po contains 280 total blocks, 26 free (91% used)

% prodos ls images/ProDOS_2_4_3.po

File name               EOF T/FT Access Created        Modified      Blocks @ Key
---------------------------------------------------------------------------------
VIEW.README             512 1/FC RW-BND 18-02-13T09:09 18-02-13T09:09     1 @ 250
...
BASIC.SYSTEM          10240 2/FF RW-BND 23-12-30T02:43 23-12-30T02:43    21 @ 42
...
PRODOS                17128 2/FF RW-BND 23-12-30T02:43 23-12-30T02:43    34 @ 7
README                  999 2/04 RW-BND 23-12-30T02:43 23-12-30T02:43     3 @ 251
    17 files in PRODOS.2.4.3 F RW--ND 23-12-29T19:07

Let's extract the PRODOS o/s and BASIC.SYSTEM files, plus the bootloader. ProDOS should execute the first .SYSTEM file it finds after it boots.

% prodos export images/ProDOS_2_4_3.po /PRODOS /BASIC.SYSTEM . --loader loader.bin

Now we'll make a new 140K (280 block) floppy boot disk:

% prodos create boot.po --name MYVOL --size 280

then import the system files and bootloader and check the listing:

% prodos import boot.po --loader loader.bin PRODOS BASIC.SYSTEM /

% prodos ls boot.po

File name               EOF T/FT Access Created        Modified      Blocks @ Key
---------------------------------------------------------------------------------
PRODOS                17128 2/FF RW-BND 25-12-28T15:20 25-12-28T15:20    34 @ 7
BASIC.SYSTEM          10240 2/FF RW-BND 25-12-28T15:20 25-12-28T15:20    21 @ 41
    2 files in MYVOL F RW-BND 25-12-28T15:19

Finally, test the image in your favorite emulator. I used VirtualII and popped my volume in the virtual Disk ][ drive. After a ProDOS splash screen, you you see the familiar Basic prompt:

            PRODOS BASIC 1.7
        COPYRIGHT APPLE  1983-92

]

My original goal was to learn how the on-disk representation worked and to manage disk images for a 6502-based breadboard computer. ProDOS is simple enough that a minimal kernel can be very small. For example I use a read-only version that's only a couple hundred lines of TaliForth. I also ported a version of the original 6502 ProDOS filestyem kernel: p8fs.