An anonymous reader quotes a report from Ars Technica: Yesterday, software developer John Brooks released what is clearly a work of pure love: the first update to an operating system for the Apple II computer family since 1993. ProDOS 2.4, released on the 30th anniversary of the introduction of the Apple II GS, brings the enhanced operating system to even older Apple II systems, including the original Apple ][ and ][+. Which is pretty remarkable, considering the Apple ][ and ][+ don't even support lower-case characters. You can test-drive ProDOS 2.4 in a Web-based emulator set up by computer historian Jason Scott on the Internet Archive. The release includes Bitsy Bye, a menu-driven program launcher that allows for navigation through files on multiple floppy (or hacked USB) drives. Bitsy Bye is an example of highly efficient code: it runs in less than 1 kilobyte of RAM. There's also a boot utility that is under 400 bytes -- taking up a single block of storage on a disk.
The report adds: "In addition to the Bitsy Boot boot utility, the ProDOS 2.4 'floppy' includes a collection of utilities, including a MiniBas tiny BASIC interpreter, disk imaging programs to move files from physical floppies to USB and other disk storage, file utilities, and the 'Unshrink' expander for uncompressing files archived with Shrinkit."