In July 1986 a small advertisement in Zzap!64 announced “THE ULTIMATE BACKUP CARTRIDGE”: Datel Electronics’ Action Replay, which “WILL STOP THE ACTION OF ANY GAME AND MAKE A COMPLETE BACKUP TO DISC”, “EVEN HEAVILY PROTECTED SOFTWARE”. It plugged into the Commodore 64’s cartridge port and had a button. Pressing it froze whatever was running, and the cartridge took over the machine.
The pitch was backups, and the backups raised awkward questions about piracy from the start. Datel, of Fenton in Stoke-on-Trent, kept adding to the cartridge, and by the end of the decade the button led to a machine-code monitor, a sprite editor, one of the fastest disk loaders sold for the C64 and a way to give yourself infinite lives. The name then went to the Amiga and to games consoles, where it came to mean something simpler: a box for typing in cheat codes.
How freezing works
Datel’s advertising explained the idea plainly. The Action Replay “works by taking a ‘snapshot’ of the program in memory so it doesn’t matter how the game was loaded — at normal or high speed — from Tape or Disk.” Whatever custom loader or protection a game had used to get into memory, it had finished its work by the time the button was pressed. The cartridge saved the memory contents to tape or disk with a loader of its own, and “ALL BACKUPS WILL RELOAD AT TURBO SPEED AND RUN INDEPENDENTLY OF THE CARTRIDGE”.
The same frozen snapshot could be examined instead of saved. The Mk II’s “code inspector” let the owner “inspect any area of memory in its ‘Frozen’ state including all VIC + SID REGISTERS”, and later versions grew it into a full monitor. After a look around, the owner could change a few bytes and restart the game where it had stopped.
The C64 versions
Datel revised the C64 cartridge often, ran it up to a Mk VI, and offered cheap upgrades to owners of older ones. These are the versions its advertising described.
- Mk I, 1986. The backup cartridge with a built-in disk fastloader. By August 1986 it was sold with the Fast Hack’em disk copier for £39.99.
- Mk II, late 1986. A “NEW IMPROVED VERSION” with the code inspector and a way to save high-resolution game screens to disk; Mk I owners could upgrade for £8.50. A DoSoft advertisement that November said it was “Designed and produced by Datel, using the programming skill of DoSoft”.
- Mk IV and Mk IV Professional, by mid-1988. Now a toolkit: a pokes and cheat mode for “extra lives etc”, a “sprite killer” that turned off sprite collisions, a monitor for the RAM inside the 1541 drive, and the Warp 25 disk turbo. The Professional added “32K operating system ROM and 8K RAM CHIP”, which Datel called “The first RAM/ROM based cartridge of its type!”
- Mk V, by January 1989. Datel’s advertising now led on the hardware: “an 8K RAM with a FULL 32K operating system ROM”, so that “ALL features are INSTANTLY AVAILABLE AT ALL TIMES”, including a “Full 64k monitor”.
- Mk VI, by November 1989. £34.99. Its advertising added “Automatic infinite lives!”, a sprite editor, a disk copier and a claim to load “202 block program in under 6 seconds” on a 1541, 1571, Oceanic or 1581 drive.
Warp 25
Warp 25 was the speed claim that made reviewers look twice. In May 1988 Commodore Disk User timed four cartridges on the same 202-block program. A stock C64 and 1541 loaded it at 1.8 blocks a second. The Action Replay’s ordinary turbo managed 10.6. Converted to Warp 25’s own format, the program grew to 214 blocks but loaded at 35.6 blocks a second, “a loading time of a mere six seconds”. That beat the reviewer’s own Dolphin DOS, a parallel-cable system that needed new chips in both the computer and the drive (see Disk Fastloaders): “Never would I have believed that my Dolphin could be outpaced by a mere cartridge system.” He put the speed down to layout: Warp 25 stored a program “on consecutive sectors and tracks”. The cost was that a disk “cannot easily be filled with Warped programs”. He called the Action Replay “the cartridge king!”
How serial-bus loaders like Warp 25 get past the 1541’s 400 bytes a second is covered in Disk Fastloaders.
The Amiga Action Replay
Datel advertised the Amiga Action Replay from April 1990, at £99.99. It plugged into the Amiga 500’s expansion port and offered freezing, an “INFINITE LIFE/TRAINER MODE”, virus detection, and a knob that slowed the machine down to 20 per cent of full speed. Its German-language manual credits Olaf Böhm and Jörg Zanger. When Jolyon Ralph reviewed the cartridge for Amiga Computing in July 1990, he found it set to “a German keymap”, with a US layout as the alternative and no UK one. He also found that Datel made buyers sign “a form to state you will not use the Action Replay for illegal activity” before sending one out.
Datel’s manual reads more like a debugger’s reference than a cheat guide. Its command summary includes a 68000 disassembler (D), an assembler and disassembler for the Amiga’s Copper (C), commands to view and edit the custom chip registers and sprites, memory search and compare, and a SETEXCEPT command that installs the cartridge’s own exception handler: “NO MORE GURU”. With it installed, a program that crashes with an address error, a division by zero or an unimplemented instruction drops into the cartridge’s monitor, which reports the exception and roughly where the faulty instruction is, instead of ending at a Guru Meditation screen. Ralph’s verdict was that “Machine code programmers will love it, being a very powerful debugging tool.”
Infinite lives by removing an instruction
The trainer finds a game’s lives counter, then finds the code that changes it. The manual walks through an example. With three lives, the owner freezes the game and types TS !3. The cartridge searches memory for that value and asks for the next one. The owner returns to the game, loses a life on purpose, freezes again and types T !2. The cartridge narrows the search to locations that went from 3 to 2, and in the manual’s example it reports one: 00014428.
From there, M 14428 sets the counter to any value. The permanent fix is TFD 14428. TF searches the program for instructions that subtract from that address, SUBQ or SUBI in 68000 code, and TFD removes them too: “SUB FOUND AT 001122 / SUBS ELIMINATED!” The game can no longer take a life away. A PC command measures an area of the screen in pixels, so an energy bar’s length can be used as the value to search for.
A virus scanner in the box
Amiga bootblock viruses spread on copied disks, and the Action Replay carried its own defences. VIRUS and KILLVIRUS search memory for known viruses and remove them, and on reset the cartridge “checks for anything resembling a virus and, if found, wipes the memory totally clean”, as Amiga Computing put it. The disk monitor’s BOOTCHK, DATACHK and BAMCHK commands write correct checksums into a bootblock, a data block or the disk’s bitmap after editing.
Console cheat cartridges
On consoles the Action Replay became a different kind of product. Mean Machines saw a Mega Drive version in October 1991: a cartridge that “fits between a game cartridge and the Megadrive cartridge port”, with a menu for entering POKEs. Players were not expected to find the addresses themselves. “Since finding the correct locations is very difficult,” the magazine reported, Datel would supply codes “for virtually all available Megadrive games”, and its advertising promised new ones in a free monthly magazine, Gamebuster. It cost £49.99 and doubled as an adaptor for Japanese cartridges. A Super Nintendo version was advertised by August 1992, and N-Force reported the Pro Action Replay in the shops that November.
On the C64 and Amiga, the owner found the cheat. On the consoles, Datel found it and the owner typed it in.
Backups, piracy and the law
A cartridge sold as “the ultimate backup” was always going to be used to copy games that were not the owner’s. In February 1987 a Zzap!64 reader wrote that Datel’s Fast Hack’em copier might “mean well for backups, but they can all too often be used for commercial and private copies”. The magazine’s reply suggested that software houses “gang up on the producers of back-up cartridges” and tax “these foul utilities”.
By 1990 Datel’s advertisements carried a “WARNING 1988 COPYRIGHT ACT WARNING”. The company “neither condones nor authorises” the use of its products “for the reproduction of copyright material”, it said, and its backup facilities were “designed to reproduce only software such as Public Domain material, the users own programs or software where permission to make backups has been clearly given”. The Amiga cartridge’s signed declaration went a step further. Its German manual still introduced the freezer as a way to make a backup copy of an original “regardless of copy protection”, and told owners that they could now write their own trainers and send them to magazines.
Sources
- Datel Electronics advertisements, Zzap!64: issue 15, July 1986, p. 87 (first advertisement); issue 16, August 1986 (with Fast Hack’em, £39.99); issue 20, December 1986 (Mk II, snapshot and code inspector, £8.50 upgrade); issue 39, July 1988 (Mk IV, Mk IV Professional, Warp 25); issue 45, January 1989 (Mk V); issues 55-56, November and December 1989 (Mk VI, £34.99); issue 66, October 1990 (Mk VI features and drive list).
- DoSoft advertisement, Commodore Computing International, vol. 5 no. 4, November 1986: the Mark Two’s programming.
- Eric Doyle, “Four Speed Cartridges”, Commodore Disk User, vol. 1 no. 4, May 1988: the Warp 25 timings and verdict.
- Datel advertisements, Amiga Format, issues 9 and 10, April and May 1990: the Amiga Action Replay, £99.99.
- Jolyon Ralph, review of the Amiga Action Replay and Nordic Power, Amiga Computing, July 1990, pp. 50-52.
- Amiga Action Replay instruction manual, German edition (Olaf Böhm and Jörg Zanger; Datel Electronics, 1990): features (pp. 1-2), trainer commands (pp. 14-16),
SETEXCEPT(p. 33), English command summary (p. 50). - Mean Machines, issue 13, October 1991: news and advertisement for the Mega Drive Action Replay.
- N-Force, issue 2, August 1992 (Super Nintendo advertisement), and issue 5, November 1992 (Pro Action Replay news).
- Letters, Zzap!64, issue 22, February 1987, p. 8.
- Ahoy!, issue 52, April 1988, pp. 56-61: Dolphin DOS’s parallel interface and fitting.
- Reader’s classified advertisement offering an “Action Replay MK3”, Zzap!64, issue 47, March 1989.
- Datel’s copyright notice, on its Syncro Express advertisement in Amiga Computing, October 1990.