Datel Action Replay

Action Replay is the brand name of a series of devices created by Datel, primarily used for changing the behavior of video games. Currently, Action Replay is available for the Nintendo GameCube, Game Boy Advance, Nintendo 64, PlayStation 2, Xbox, Nintendo DS and PlayStation Portable.

Method of operation

Action Replays that were capable of saving the system's state to tape or disk all operated in broadly the same way. By attaching to the computer's memory bus (via the Zorro expansion slot on the Amiga), [cite news | url = http://amigahardware.mariomisic.de/cgi-bin/showhardware_en.cgi?HARDID=737 | title = Amiga hardware | date = 2008-06-02 | accessdate = 2008-06-02] all memory access by the processor could be monitored. By keeping track of all writes to hardware registers (for example, to the video or sound hardware) the Action Replay could keep a complete copy of the state of all those registers in its own internal memory. [cite news | url = http://www.mways.co.uk/amiga/howtocode/text/actionreplay.php | title = Action Replay cartridges | date = 2008-06-02 | accessdate = 2008-06-02] This state could then be saved, along with the contents of the computer's RAM for later re-loading. By pressing a button on the Action Replay, an interrupt loaded a special monitor program from the Action Replay's ROM which could then be used to load, save and modify the computer's memory. It was even possible to alter CPU registers of the paused code, and later revisions included a complete disassembler. Some developers used this feature when writing their own games. Cheating was possible by altering values stored in RAM.

A knob on the Amiga version of the Action Replay MKIII allowed games to be slowed down, to make them easier. This worked by intercepting vertical blank interrupts and running a wait loop until at least the next vertical blank. This did, however, have the limitation of only being able to reduce game speed by 50% or more.

The Action Replay was a formidable opponent for anyone trying to prevent their game code or graphics being ripped, or their game saved for later re-loading. A few weaknesses were discovered in the Amiga version. It was possible to detect when the interrupt (hardware level 7, unmaskable) which the Action Replay used had been triggered, but only after the Action Replay monitor program had exited. At best the programmer could then choose to crash his program deliberately, making saved copies crash as well. However, it was possible to patch code which did this using the monitor program, so even that was not a total defence. Another technique involves using the CIA time-of-day clock alarm to detect when more than a certain amount of time has passed without it triggering an interrupt, implying that the Action Replay monitor program was running. Later revisions of the Action Replay defended against this by resetting the CIA time-of-day clock. Perhaps the only undefeatable method of foiling the AR is to use a one-time co-processor program to alter hardware registers. The AR is unable to monitor writes by the co-processor, but it can read the co-processor program to determine what writes it makes. By using a one-time program to set up hardware registers, then changing the program to one that ignores them it becomes impossible for the AR to know the true state of those registers (which are write only). Using this technique the programmer could blank or corrupt the screen on leaving the AR monitor.

Later Action Replays which only supported cheat codes and had no monitor program, worked by monitoring memory access for certain triggers or by overwriting certain memory addresses at particular times (such as once per frame, or on a timer). On systems such as the Dreamcast, this could even be done entirely in software.

Some console systems require all bootable media to contain cryptographically signed code, or require specially manufactured discs as a form of copy protection. As Action Replay systems are rarely granted an official licence, Datel has to find ways around these issues. Sometimes the presence of special hardware is enough, but on systems that use software only Action Replays it appears that Datel found other ways of making it's code work. The PS2 version of the Action Replay used specially manufactured discs, with the centre part of the disc containing the copy protection information cut from officially licensed games (presumably bought in bulk somehow, perhaps bankrupt stock) and glued to the middle of the Action Replay disc.

Typical features

General:
* Infinite lives, ammunition, health, time, money etc.
* Invulnerability, permanent power ups, no collision detection, walk through walls, one hit kills etc.
* Obtain any item in the game, even those not normally obtainable (e.g. debug or removed items).
* Access or warp to any level, even those not normally accessible (e.g. test or unused levels).
* Activate debug menus, normally used by programmers when testing and debugging a game. Typically options include cheats, level warping and display of internal game data not normally viewable by the player.
* Download, upload, import and export save games to the internet or storage device.
* Save game state to disk, so it can be restarted from that point even if the game does not support saving.
* Region free operation.
* Bypassing of copy protection for loading of copies/backups on CDR/DVDR or HDD, or homebrew software.
* Media player for music and video.

Criticisms

Datel, the maker of Action Replay, has received several criticisms from the gaming world over its products. One of the most popular complaints is the so-called "planned obsolescence" where codes for a just-released game require the most recent version of the cheat software.

Datel as of now has encrypted the codes on the Action Replay for PS2, GC and GBA; this was meant to stop hackers from translating its codes for use in other cheating devices, but it prevents users from making their own codes for their games. It also prevents the creation of codes using a template. There is, however, a programme was created called 'GCNCrypt' that decrypts and encrypts Action Replay codes for the Nintendo Gamecube, making editing and hacking of codes possible. Cheat codes normally involve a memory address, a value, and sometimes a trigger that says when the code is activated (always on, on at the start, on after a certain button press); because of this, for some games it is possible to create a code template, and derive hundreds of codes by modifying the values. For example, in a role-playing game, one can use a code template and a table of values to create a code that will give any character, any piece of equipment in the game. By encrypting the codes, it is not possible to use such a template, and any code must be created and distributed by Datel; because of the sheer number of codes that can be created in this fashion, it is not plausible for Datel to release a list of codes with this versatility. A new Action Replay for the DS, which allows cheat codes (the previous Action Replay only managed game saves), uses unencrypted codes, and has a trainer toolkit available that allows users to create their own codes.

Sometimes, the codes for certain first-party games on the GameCube make it impossible to go further into the game with cheats activated (e.g. "Pikmin" and "Star Fox Adventures"). Other times, cheats freeze the game in the first stage (e.g. if cheats are activated at the beginning of "Super Mario Sunshine" and "Metroid Prime", the game will freeze, and the system will have to be switched off). Also, in "Pokémon" games, advanced-generation ones especially, using the "Instant Win" code causes the glitch character "??????" to appear, usually resulting in a corrupted game. Nintendo does not license the Action Replays for its versions. Datel's website often indicates when a code should not be used.

The PS2 Action Replay version occasionally corrupts the memory cards, leaving corrupt files on the card that cannot be deleted by the PS2. The Action Replay can, however, fix the memory card by formatting it, but the corrupted data cannot be restored.

Action Replay codes allow access to game features not normally available to players. One notorious example is the "Hot Coffee" mod for which allowed users to access an adult sex simulation that was removed from the game before release, but for which code remained in the game. Rockstar, the creators of the game, came under heavy criticism for releasing the game with the code in it, despite it not normally being accessible.

Cheating in online games is also usually frowned upon, with game companies making efforts to prevent and detect it. However, with an Action Replay it is possible to cheat without being detected, or in a game for which there is normally no way to cheat. Examples include Phantasy Star for the Dreamcast, in which it was possible to manufacture items using an Action Replay in the offline mode, and then carry them over to the online mode undetectably. There was no way to determine if the item had been manufactured or legitimately won. Of course, it is also possible for the Action Replay to disable anti-cheating code or otherwise prevent detection, however since modern versions only allow codes to be created by Datel and they have so far not taken this route, there are no such hacks for current generation systems.

Versions for computers

* Commodore 64
** Action Replay
** Action Replay II
** Action Replay III
** Action Replay IV (1988)
** Action Replay VI (1989)
* Commodore Amiga
** Action Replay (A500 cart / A2000 CPU card)
** Action Replay (A1200 card)
** Action Replay Mk II (A500 cart / A2000 CPU card)
** Action Replay Mk III (A500 cart / A2000 CPU card) (1991)
* PC
** Action Replay PC (ISA card) (1994)

Versions for video game consoles

Late 8-bit era

* Nintendo Entertainment System
** Pro Action Replay
* Sega Master System
** Pro Action Replay

16-bit era

* Sega Mega Drive/Sega Genesis
** Action Replay
** Pro Action Replay
** Pro Action Replay 2
** Pro CDX (Action Replay) for the Mega-CD
* Super Nintendo Entertainment System
** Pro Action Replay
** Pro Action Replay MK2
** Pro Action Replay MK3

32/64-bit era

* Sega Saturn
** Pro Action Replay (also available with 4M RAM expansion)
* PlayStation
** Action Replay (1995)
** Pro Action Replay (1996)
** Action Replay CDX (1997)
* Nintendo 64
** Pro Action Replay (1999)
** N64 Equalizer

ixth generation

* Dreamcast
** Action Replay CDX
* PlayStation 2
** Action Replay 2 (2000)
** Action Replay 2 V2 (2001)
** Action Replay MAX (2003)
* Xbox
** Action Replay (2002)
* Nintendo GameCube
** Action Replay (2003)
** Action Replay Max Evo (200X)
** Action Replay (2006, works on Wii)

eventh generation

* Wii
** Action Replay Powersaves(2007)

Versions for handheld consoles

* Game Boy
** Pro Action Replay
** Action Replay Online
** Action Replay Extreme
* Sega Game Gear
** Pro Action Replay
* Game Boy Color
** Pro Action Replay
* Game Boy Advance
** Action Replay (2001)
** Action Replay Duo (2005)
* Nintendo DS
** Action Replay Duo (2005)
** Action Replay DS (July 2006)
* Playstation portable
** Action Replay 1GB (October 2008)

ee also

* GameShark
* Game Genie
* Multiface
* Code Breaker

References

External links

* [http://www.codejunkies.com/ CodeJunkies.com] – Official Action Replay website
* [http://nexus23.org/warfare/content/view/344/35/ Nexus23.org] – Tribute To Action Replay Mk6 and Mk3