About ProDOS-8

Professional Disk Operating System

ProDOS stands for: Professional Disk Operating System.
ProDOS was released for the Apple II series of computers in January 1983.
ProDOS was distributed by Apple until 1993.
ProDOS is the last official operating system usable by all 8-bit Apple II series computers.

The Apple II was an 8-bit computer.
The Apple IIgs was an 16-bit computer, which had backwards compatibility with the 8-bit Apple II’s.
When the Apple IIgs was released, it came with a 16-bit version of ProDOS, officialy called ProDOS-16. ProDOS-16 was officially replaced by GS/OS once it was ready.
When the Apple IIgs was released, ProDOS for 8-bit computers was version 1.2, and renamed to ProDOS-8.

The original Apple II DOS only has built-in support for 5.25” floppy disks. However, ProDOS includes support for 3.5” disks.
DOS has no subdirectory support. ProDOS has support for hierarchical subdirectories.
The maximum volume size supported by DOS is 400k. ProDOS supports volumes up to 32mb.
ProDOS includes RAM disk support on machines with 128kB or more RAM.
ProDOS supports the RTC (Real Time Clock), however only the Apple IIgs has a RTC built-in.

The last official release of ProDOS was 2.0.3 in 1993.
On September 15th, 2016 John Brooks released the 2.4 version of ProDOS on the 30th anniversary of the introduction of the Apple IIgs.
Originally ProDOS did not include support for the original Apple ][ or the ][+, however This release added support for the Apple ][ and ][+ models, making it the first release of ProDOS that would run on ALL Apple II’s.
The release includes Bitsy Bye, a menu-driven program launcher that allows for navigation through files on multiple floppy drives.

The developer of ProDOS after 2.0.3.
Apple ][ developer since 1979.
Professional game developer since 1987.
In 1995, cofounded Blue Shift, Inc. in San Jose, CA., a company which develops video games, embedded systems, and provides engineering consulting services.