Atari 2600 Limitations
Every console manufacturer at every generation has had a decision to make on how much memory (RAM) could be put in the console with an eye on production costs. The VCS designers back in the 1970s were severely constrained RAM-wise and could afford to add just 128 bytes of RAM to the design. Read-only memory used in game cartridges for the VCS was also expensive and it was only expected that games would use a maximum of 4K (4096 bytes) of ROM in the plug-in cartridges to contain all of the game code. In fact many early games used just 2K of ROM.
Now, 4K is not a lot for game program code and 128 bytes of RAM is a real pain. This all meant that probably the biggest concern for a developer was to keep the ROM size down and minimise the number of variables that the game needs to record during gameplay and this would of course lead to compromises in the amount of change that could be fed into the screen graphics. In vintage consoles and computers, larger amounts of RAM mean that less compact code can be produced that can execute faster and so do more in the limited time available to manipulate the screen, potentially even using tricks such as re-writing portions of the code as it executes (self-modifying code) which is impossible in ROM.
Enter The Supercharger
The Starpath (formerly Arcadia Corporation) Supercharger unit plugs into the 2600 cartridge slot and boasted the claim that it would bring ‘action and detail not possible in conventional cartridge systems’. This was a little misleading perhaps as there were no graphics hardware changes in the cartridge which was in fact a 6K (6144 bytes) RAM expansion. The cartridge was designed to reduce the memory restrictions on the game developers, freeing them to produce larger code focused more on performance with more variables recorded and greater graphical changes made possible through techniques not possible when space is the overriding concern.
It may seem a small amount but this extra memory was nothing to be sniffed at in those days and some of the Supercharger games really show the effect of having more space to breathe. However, the Supercharger also includes a cassette interface so that programs can be loaded directly into the extra RAM from cheap-to-produce (and so to buy) tapes rather than more expensive ROM cartridges with their expensive memory chips. With code loaded into the RAM from tape the Supercharger runs game code just like any ROM cartridge, in fact some enterprising hackers dumped released cartridge contents to tape so that the cartridges could be copied and run from the Supercharger.
Loading from cassette brought another benefit for Supercharger games – the potential for multi-load games. These games could be much larger if split into stages with each stage loaded from cassette into a portion of the Supercharger RAM as needed. Of course cassette loading could also bring the pain and problems of audio levels that would come to haunt many an 8-bit home computer user.
Technology Races On
Similar benefits to those delivered by the Supercharger can be seen in later cartridges for the 2600 that had much higher ROM capacities, sometimes included small amounts of extra RAM and are a world away from the early Atari releases. The 4K ROM limitation was eliminated using a technique known as ‘bank-switching’ where larger ROMs could be read in units or “banks” of 4K. The currently used 4K bank is selected by the cartridge electronics usually by the game code reading special locations in the ROM so that ROMs of 8K, 12K, 16K became possible, leapfrogging the 6K available in the Supercharger.
As time moved on and cartridges became larger and cheaper the Supercharger advantages over standard cartridges for game creation were lost.
Running Supercharger Games
Atari VCS/2600 emulators such as Stella can emulate the Supercharger and run the games accurately in modern computers. For the real iron, Superchargers can be found for sale in the wild, they are uncommon but certainly not ultra-rare (except in the eyes of some eBay sellers) but getting a full set of games will be tricky. Audio files of the games are easily found and can be loaded by connecting the headphone socket of your phone, tablet or computer directly into the Supercharger and should be more reliable than the cassette tapes.
Should you find it difficult to obtain a working Supercharger, there is another option for running the games on actual hardware. The Harmony cartridge can run all of the Supercharger games, even multi-load games where the parts have been combined into a single binary file. You can find the Harmony cartridge at AtariAge.
Starpath produced a small well-regarded library of ten games that were generally available and two that were available by mail order. Five of these games were multi-load. Highlights of this small catalogue are:
Atari produced Star Raiders for the 2600 but came nowhere near to doing justice to the Atari 400/800 computer original. Phaser Patrol does a far better job re-creating the frantic action of trying to clear your 36 sector galaxy of enemy fighters and defending your star bases. The game has all of the original’s damage indicators for your ship and dogfights are just as hectic as the computer original. This Supercharger version does not require the keypad that was included with Atari’s Star Raiders – the galaxy map is activated and deactivated by flicking the console’s ‘Left Difficulty’ switch which is a very nice touch.
The Official Frogger
Parker Brothers released a version of Frogger for the standard 2600 but this version for the Supercharger blows it out of the water.The difference is astounding. The Supercharger version has more moving graphics, these graphics are much more detailed and animated with music playing throughout. You’d be convinced that the hardware had been greatly improved by the Supercharger if you’d bought this new.
A role playing game no less! For the 2600! OK, it’s limited but there are monsters to kill, loot to be had and a dragon to defeat in this multi-load title. Firstly your character, represented by a white dot, has to explore a landscape and gain loot from random encounters to the point where you can gain access to the castle and locate then defeat the dragon. Fighting is carried out using a small text display that presents combat (and other) options and lets you know the result of battles.
Escape from the Mindmaster
This title is a little different. It’s a first person 3D multi-level maze filled with puzzles that require you to find key blocks and place them in holes of the same shape. Find and fit them all and the next level is unlocked. There are also mini-games in some maze rooms that are more reaction-based challenges and provide chances to increase your score. Oh, and there’s an alien stalking the corridors that can end your game very very quickly.
Original post can be found at Retro Games Collector
The Starpath (Arcadia) Supercharger for Atari 2600 – a retrospective