Latest release of ProDOS is 2.4.2

ProDOS 2.5 has been announced but is not available yet.

ProDOS 2.5

  • No downloable disk image is available yet.


  • Lowercase volume support.
  • Lowercase filenames match what GS/OS and the Finder use.
    If an application does not support lowercase filenames they will read the directory and see uppercase filenames.
    There is no case sensitivity in the filenames.
  • Can pass relative path arguments to commands, such as:
CAT ..
PREFIX ../..
  • Year has been expanded from 7-bits (127 years) to 10-bits (1,024 years) to allow date support until the year 2924.
    There is still a year 2040 problem where the 24-bit timer on the Apple IIgs will wrap around to 1900.

Bitsy Bye

  • Upgraded version of Bitsy Bye
  • Bottom border in Bitsy Bye has been removed so the number of files that can be viewed at once is has increased from 20 to 22.
  • Merges in features from Bitsy Boot:
    • When using GS/OS, and running ProDOS, pressing DELETE will take you back to the GS/OS Finder.
    • Can boot to a slot by selecting it and pressing RESET.


  • Previously, on the Apple IIe or IIc, if you hit the DELETE key you would get the checkerboard. Now if you hit the delete key it will actualy delete the character.
  • New online command will list devices in the system showing the slot, drive, volume name, and free space.
  • Dash (-) will run ProCMD files
    • Runs CMD files at $4000 (ProCMD)
    • Now allows for file arguments
-binfile arg1,arg2

51-file limit on the root directory removed

  • The new ProDOS 2.5 boot loader will find the ProDOS file anywhere in the root directory linked-list.
  • ProDOS 2.5 should allow unlimited files in the root directory level.

ProDOS 2.5 on the Apple /// ?

  • ProDOS 2.5 includes a new Boot Loader that works on Apple ///.
  • With this new Boot Loader, along with some future development work, ProDOS could potentially run on the Apple /// !

New Boot Loader

  • The new boot loader can also load all, or just part, of the ProDOS file at boot so new versions of ProDOS can append machine-specific drivers after the core ProDOS kernel without having to load all drivers on all platforms during every boot.

Looking for Contributors

Please contact John Brooks to get involved.

  • Code writers
  • Testers

In-Progress Features

  • Modify Global Page so it’s easier to turn on/off features without changing the machine type.
    Features like ike the large-date support or the lowercase filenames could then easily be disabled to support apps which do not play nice with those features.
  • Modify COPY+ and Cat Doctor to support lowercase filenames and the longer-date.
    When COPY+ doesn’t see a normal ProDOS filename it assumes that the disk is DOS3.3 and tries to use the DOS3.3 parser.

  • Conversion of ProDOS source code to Merlin32