The Atari 400/800 home computers were well-established and quite successful in the games market by the time the Atari 5200 console was released in 1982. The 5200 shared the chips and architecture of the 400/800, and it appears on the surface that it would have been a trivial matter to have the 5200 support games on cartridge that already existed for those machines. In fact, those game cartridges likely comprised the best quality home computer game cartridge library that existed in 1982, for any machine.

We know in retrospect that the 5200 was not a success. And it seems like launching with a whole bunch of high quality games would have been really helpful. That, and a better controller, would have probably saved the 5200 from mediocrity. We also know in retrospect that forsaking compatibility with the 8-bit computers was a mistake in Atari's mind as well, since they corrected this deficiency with the XEGS.

Why did Atari forsake compatibility with the existing 400/800 game library?

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    If anything, I would have thought it would have been made to be compatible with the 2600 VCS. There were probably exponentially more game cartridges for that console than the 400/800. I know that one deciding factor to upgrade out Nintendo 64 to the GameCube was because of an adapter that allowed my sons to play their N-64 games. Something similar might have saved Atari. Commented Aug 30, 2018 at 20:03
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    @BillHileman Not disagreeing that 2600 compatibility would have been helpful, but that machine is a completely different architecture from the 400/800/5200.
    – Brian H
    Commented Aug 30, 2018 at 20:11
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    Maybe customer experience concerns re: an existing library that assumes a machine with a keyboard? That could be used to justify a slot change at least; and if you're not planning to exploit that library directly anyway, maybe then is when you start removing computer-style bits of the architecture? I'm guessing, as ever.
    – Tommy
    Commented Aug 30, 2018 at 21:29
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    @BillHileman There was an accessory called the Game Boy Player that let you play Game Boy Advance on the GameCube, but I've never heard of anything that let you play Nintendo 64 games on the GameCube.
    – user722
    Commented Aug 30, 2018 at 22:28
  • @RossRidge you are correct, my memory was faulty. It was indeed that kind of adapter. My sons still have countless game cartridges for their DS<whatevers> that they still use today. While it was a novel idea, they really didn't use it much now that I more correctly recall, but it was kind of neat to watch them play on the attached TV. Commented Aug 31, 2018 at 13:39

4 Answers 4


At that point in time, Atari had separate divisions for the Home Computer market and the Consumer Electronics, or console, market. There was a lot of competition between the divisions.

The Consumer Electronics division was the pride of the company due to all the cash that was rolling in thanks to the Atari VCS(2600), and it seems there was a bit of hubris involved in their design of the 5200.

The rivalry between divisions manifested itself to the point where the same video game license was made by completely different programmers in the different divisions, despite the fact that the same code could have been highly reused between the two platforms. I think Mario Bros. is a good example of this, the 5200 and the 8-bit versions are completely different games.

I believe this situation is well documented in the book "Atari: Business is Fun" if you would like much more information about how Atari was being run at the time.

The XEGS machine came later, under completely different management than had produced the 5200.

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    "if you would like much more information about how Atari was being run" - or not run depending on your definition. Commented Sep 4, 2018 at 20:25
  • @MauryMarkowitz lol - too true
    – Troff
    Commented Sep 6, 2018 at 17:14

While I think Troff's answer is very insightful about the environment inside Atari at the time, I think it might have something more to do with how licensing of popular arcade games was handled at the time.

In particular, it was common practice for a company such as Nintendo to sell the rights for a game based on the target platform. For example, Nintendo licensed Donkey Kong to Coleco for the home game consoles while Atari received the rights for the home computers.

While it would be wonderful to simply cap the answer at who had the rights, it seems that the playfield is riddled with exceptions. For example, when the Coleco ADAM version of Donkey Kong was released (considered a home computer), the version on that platform was developed by Coleco, not Atari as you would have expected from above. Coleco seemingly felt that since the ADAM was an expansion module of the underlying ColecoVision game console, the ADAM port was just an enhanced ColecoVision version and thus within the terms of their license agreement. This ended up as a lawsuit raised by Atari and ultimately caused the ADAM version to get pulled, but not before it had already been widely distributed.

In regards to Mario Bros., it does seem that the 400/800 and 7800 versions were developed by Atari Corp. while the 2600/5200 (*1) versions were developed by Atari, Inc. Historically, Atari Inc. was the original Atari company that Nolan Bushnell founded while Atari Corp. was the Warner sell-off of the home computer and console division to Jack Tramiel in July 1984.

Given the timing of the publishers, it would suggest that perhaps Atari didn't have the rights to the home computer versions when the original 5200 port was developed and when they finally did acquire them, they rewrote the game; perhaps the original 5200 code wasn't suitable as a basis for porting to the other home computers? I haven't done a comparison of the game across platforms, but perhaps there is some commonality across the home computer versions.

*1 - The 7800 wasn't released until after Tramiel took over.

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    Actually, this is a very insightful answer, too. From a licensing perspective, if the 5200 and 400/800 cartridges were interchangeable, then to release a game in that cartridge format may have then required the license to both the console and home computer platforms. I hadn't thought of that before, and it may also explain why Atari made some seemingly arbitrary changes in the 5200 from the 400/800: the memory locations of many things were changed. Many people have complained about this because it complicates moving code between the two, but that may have been the point all along.
    – Troff
    Commented Jan 8, 2019 at 22:52
  • @Troff: I don't know that licensing was yet a consideration, since I don't think it was clear (and it actually still isn't) what aspects of a game would need to be licensed beyond copyrighted artwork and sounds, along with any trademarked properties. The line between computers and video games was never really clear (99% of computers today would be considered "video game systems" under the definition used by Nintendo to block Tengen's Tetris cartridge because they lack floppy drives). I wonder what would have happened if Tengen, rather than claiming that the NES was a "computer",...
    – supercat
    Commented Jan 28, 2019 at 19:32
  • ...had instead claimed that what they licensed from Spectrum Holobyte was the original audiovisual content created by SH (which the Tengen cartridge used), without admitting that any license from ELORG (Russian creators of Tetris) would have been needed for a falling tetrominos game that doesn't use any of Elorg's graphics or sound (beyond the tetrominos whose design was in the public domain anyway).
    – supercat
    Commented Jan 28, 2019 at 19:34

Joe Decuir has posted on Facebook some laments about how adding a couple more lines to the 400/800 cartridge slot - and including the TIA - would've made the 400/800 backwards-compatible with the 2600.

The 400/800 began as a project to design the replacement for the 2600 since Atari's engineers assumed the shelf life for the 2600 - known as the VCS back then - was 3 years. But the Warner-chosen Atari CEO Ray Kassar saw the margins the Apple II was earning and decided Atari should also sell a profitable computer line to compete with Apple and so that project was turned into a computer project.

The 5200 was a return to the original intent of the 400/800 project. Atari's engineers wanted the 5200 to be backwards-compatible with the 2600 but the Warner managers nixed the idea. Their logic behind the decision was "why would anyone want to play old games on a newer advanced system?" And there was some logic to that considering the much later Nintendo Super NES/Super Famicom wasn't backwards compatible with the NES/Famicom and yet it was still a success. Had the 5200 been backwards-compatible, then Atari Inc would've either had to have made the 5200 cartridge slot basically a souped up 2600 slot - like the later 7800 - or offered it as a 2nd cartridge slot. Had it been a single slot, then the 5200's cartridge slot wouldn't have been ZIF. And Atari also would've had to have used DB9s instead of the 5200's DB15s or offered both thereby making the system even more expensive to manufacture. It should be noticed that Atari's own engineers wanted the 5200's joysticks to be self-centering and protested against Warner's decision not to do that even before the console was released...

A lot of this is covered in the Atari Inc - Business is Fun book.


Another factor not yet mentioned is that even if Atari had tried to make the 5200 compatible with the 400/800, the 5200 probably wouldn't have been able to usefully handle all games for that platform (at minimum, it would have been difficult to support games that use the keyboard--even if only for initial setup--without building a keyboard into the 5200). From a customer-support standpoint, having a console support 90% of the games for the Atari 400 would be much more problematical than having it support 0%. Perhaps a good approach might have been to construct the cartridge slot in a way that existing cartridges for the 400 wouldn't fit without modification, but manufacturers could add a notch to make the cartridges compatible with either the 400 or the 5200, or a projection that would make cartridges fit in the Atari 5200 only, depending upon which machines the code could support.

If the fact that many Atari 400 cartridges could be made to work on the 5200 by cutting a notch was an "open secret", people who discovered from magazines or other sources that the 5200 could support the games they wanted might buy a console for that purpose, but the tech support department would be under no obligation to answer complaints that games which were sold for the 400 didn't work on the 5200.

  • Really? Even if you plug a 400/800 cartridge into a 5200, how does it translate the 5200 controller input into something the 400/800 cartridge can understand?
    – Dronz
    Commented Sep 30, 2020 at 0:55
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    @Dronz: I was suggesting a hypothetical in which the only cartridges that would work on both would be those with a special "dual compatibility" housing. If the memory map had been kept essentially the same, a 16K dual-mode cartridge could have had 14K of code that is used on both systems, 1K that is used only on the 5200, and 1K that is used only on the 400/800. As for notch-cutting, the usefulness of that would depend upon whether the 5200 went with its actual controller design, or something closer to the 400/800 design.
    – supercat
    Commented May 21 at 17:15

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