Apple IIGS ROM Revision Summary
Apple IIGS Technical Note #26: ROM Revision Summary (Apple Computer, Inc., Developer Technical Support; written by Rilla Reynolds, October 1987; revised by Matt Deatherage, September 1989) is Apple's own account of what changed between Apple IIGS ROM versions.
What is in it
[edit | edit source]- Apple's naming: ROM 0, ROM 1 and ROM 3. ROM 2 was skipped "since there was already enough confusion about the first version, ROM 0, and the second version, ROM 1".
- ROM 3 is 256K, double the size of ROM 1, and machines began shipping with it in August 1989.
- ROM 1 requires System Software 2.0 or later; ROM 3 requires System Software 5.0 or later. System software no longer supported ROM 0 by 1989.
- Authorised dealers could upgrade machines with serial numbers lower than E704... to ROM 1 on request.
- Hardware changes visible in the firmware notes for ROM 3: the new keyboard microcontroller that allows finer mouse tracking and the keyboard-mouse feature, and the new CYA chip that handles text page 2 shadowing and the power-up bits.
- The Window, Menu, Control, Line Edit, Dialog, Scrap, Font and List Managers moved into ROM on ROM 3.
Download: Apple IIGS Technical Note 26 ROM Revision Summary 1989.pdf