anti-m/README.md

99 lines
3.3 KiB
Markdown
Raw Normal View History

2019-03-09 20:30:57 +00:00
# Anti-M
2019-03-16 15:49:00 +00:00
Boot any Apple II disk on any Apple II
2019-03-09 20:30:57 +00:00
## What is this?
Many early Apple II games only worked on the original Apple II or Apple ][+.
They refuse to boot on later models, often displaying an "M" error code. This
2019-03-16 15:49:00 +00:00
was due to overly aggressive copy protection; late in the boot process, there
is code that checksums the ROM and reboots if it's not recognized. The games
2019-03-09 20:30:57 +00:00
themselves would work fine if they were allowed to boot past this ROM check.
2019-03-16 15:49:00 +00:00
Other games fail on an enhanced Apple //e, due to subtle differences between
6502 and 65c02 processors. Still others fail on an Apple //c or IIgs, due to
changes in the boot PROM code. Then there are some _very_ early games that
require a 13-sector drive.
Anti-M uses a modified boot PROM that can boot any disk, then controls the
game's bootloader long enough to bypass the ROM check and patch any 6502-
specific opcodes. The result: you can boot any Apple II disk on any Apple II.
2019-03-09 20:30:57 +00:00
## How do I use it?
Boot the Anti-M disk. When it prompts you to insert your original disk, do so,
then press `<RETURN>`. The game should boot normally.
## Which games are supported?
2019-03-12 01:04:37 +00:00
- Beer Run (Sirius)
- Bug Attack (Cavalier)
2019-03-10 14:28:28 +00:00
- Choplifter (Broderbund) (*)
- David's Midnight Magic (Broderbund) (*)
2019-03-10 14:28:28 +00:00
- Dueling Digits (Broderbund)
- Eggs-It (Gebelli)
2019-03-10 14:28:28 +00:00
- Frogger (On-Line Systems) (*)
2019-03-12 01:04:37 +00:00
- Gamma Goblins (Sirius)
- Genetic Drift (Broderbund)
2019-03-16 15:49:00 +00:00
- Hard Hat Mack (Electronic Arts) (*)
- High Orbit (Gebelli)
- Horizon V (Gebelli)
2019-03-10 14:28:28 +00:00
- Jawbreaker ][ (On-Line Systems)
2019-03-11 12:54:25 +00:00
- Juggler (IDSI)
2019-03-10 14:28:28 +00:00
- Labyrinth (Broderbund)
- Lazer Silk (Gebelli)
2019-03-10 14:28:28 +00:00
- Lunar Leepers (On-Line Systems)
- Neptune (Gebelli)
2019-03-12 01:04:37 +00:00
- Orbitron (Sirius)
2019-03-10 14:28:28 +00:00
- Pest Patrol (On-Line Systems)
- Phaser Fire (Gebelli)
2019-03-12 01:04:37 +00:00
- Quadrant 6112 (Sensible Software)
- Red Alert (Broderbund)
- Russki Duck (Gebelli)
2019-03-10 14:28:28 +00:00
- Seafox (Broderbund)
- Serpentine (Broderbund) (*)
- Sky Blazer (Broderbund)
2019-03-12 01:04:37 +00:00
- Space Eggs (Sirius)
- Space Quarks (Broderbund)
2019-03-10 14:28:28 +00:00
- Star Blazer (Broderbund)
2019-03-12 01:04:37 +00:00
- Star Thief (Cavalier)
2019-03-11 12:54:25 +00:00
- Trick Shot (IDSI)
- Zenith (Gebelli)
2019-03-16 15:49:00 +00:00
- all 13-sector disks (e.g. Epyx, Edu-Ware, many others)
2019-03-09 20:30:57 +00:00
(*) later re-released with different copy protection. Only the first release
requires Anti-M.
## Does Anti-M patch my original disk?
No! All patches are done in memory only. If you reboot your original disk
2019-03-16 15:49:00 +00:00
(without running Anti-M), it will fail as usual, because the ROM check or other
incompatible code is still there.
2019-03-09 20:30:57 +00:00
## Can I use Anti-M from a hard drive?
2019-03-16 15:49:00 +00:00
Yes! Copy the `ANTI.M.SYSTEM` file to anywhere on your ProDOS hard drive and
run it with your favorite launcher. Bonus feature: when launching Anti-M from
a hard drive, it will skip the prompt and immediately boot slot 6, drive 1.
2019-03-09 20:30:57 +00:00
## History
2019-03-16 15:49:00 +00:00
v1.1 - 2019-03-16
- support booting 13-sector disks
- support booting disks on Apple //c and IIgs which would otherwise time out
looking for a boot sector (SpiraDisc, some early EA games)
- bypass a peripheral scan in some games that would hang on some peripherals
and crash others and require a hardware power cycle in order to reboot
properly (SpiraDisc)
- support multiple versions of "David's Midnight Magic"
- remove "unsupported game" error, always continue booting
- bypass prompt if launched from hard drive (press the open- or closed-apple
key on startup to show the prompt)
- minimum requirements lowered to 48K Apple ][+ (still useful for booting
13-sector disks)
2019-03-12 01:04:37 +00:00
v1.0 - 2019-03-11
2019-03-09 20:30:57 +00:00
- initial release