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When was the external ROM cartridge first used and what home computer was the first to use it?

  • You could ask what the first HC was that came with a ROM cartridge (and couldn't do without): For the Sinclair QL in its first incarnation, they couldn't fit the ROM into the allotted space and had to fit it with a "dongle" for the ROM slot that held part of the operating system - This was later removed with newer OS revisions. – tofro Jul 1 '18 at 8:21
  • ... which was exactly the other way round as the Atari ST and the Amiga that shipped with a small loader to load the OS from disk before they could make the final OS fit into the ROM space available. – tofro Jul 1 '18 at 12:20
  • @tofro - I vaguely recall reading a review able the brand new (at the time) QL and the dongle was called the "kludge" I believe. Maybe it was the magazine's own take on the matter, but I seem to remember it being portrayed as a semi-official name. – Greenonline Jul 4 '18 at 21:39
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    @tofro It wasn't so much that they couldn't make the Amiga OS libraries fit into the ROM space, its that production was so rushed they were updating the ROM code constantly almost right up until the release date. They put the KickRAM workaround in the A1000 in place of the planned ROMs (same size) to get around that and allow the ROM code to be loaded at boot time so that they could iterate the ROM code right up until it was time to dup the floppies and keep iterating it after the release of the computer. – mnem Sep 17 '18 at 5:41

The Atari 400/800 and the original Texas Instruments TI-99/4 were both released at approximately the same time in 1979, and both featured a user-accessible edge connector designed to accept the plug-in ROM cartridges that are familiar to most 1980s gamers.

Both the Atari and the TI-99/4 clearly meet the common definition of "home computer", but it should be noted that hardly any of the TI model were sold. The better known and successful TI-99/4A did not arrive until 1981. Also, strict limitations placed on 3rd Party Development by TI meant that very few software titles, including on cartridge, were ever released for it.

In contrast, the Atari 400/800 went on to be one of the most successful home computers of the 1980s, spawning many compatible, enhanced, and cost-reduced successors. All of the 8-bit Atari home computers retained a slot for user-pluggable ROM cartridges.

  • Minor nit: the Atari 400/800 cartridges were, by design, not "external" but instead needed to be contained within an RF shield. – supercat Jul 2 '18 at 17:06
  • @supercat I was taking liberties to use the term "user-accessible" rather than "external" - meaning designed for the user to routinely remove/insert cartridges in daily use - no disassembly required. – Brian H Jul 2 '18 at 17:54
  • I'd consider the Atari 400/800 as somewhere between a computer that would require some bona fide disassembly to access a card slot, and one which uses cartridges that extend outside the machine. On something like the Atari 2600, there's no particular size constraint for cartridges, and many such machines have had at least a few cartridges designed for them that are much larger than the designers had probably anticipated. By contrast, the Atari 400/800 would be limited to what would fit within the RF cage. – supercat Jul 2 '18 at 18:44
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    Not to suggest in any way that your answer was "wrong"--merely to suggest that other readers might find the "middle ground" nature of the 400/800 interesting. – supercat Jul 2 '18 at 18:45
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    Sure. I see what you are saying. The original NES didn't come out until 6 years later, and the cartridges for it completely disappear inside the machine. I was sort of thinking of the NES when I said "plug-in ROM cartridges that are familiar to most 1980s gamers". – Brian H Jul 2 '18 at 20:25


That question is problematic in several ways due to its unnecessarily narrow focus. For one, by restricting it to external, it would exclude machines that had their modules covered by a lid (like the Atari 800). Further is tying this to home computers excluding every machine using ROM modules that does not fall into this, and that's the next point, rather fuzzy definition of a home computer.

Now if we rephrase it as

"What was the first personal computer with an intended use of user pluggable ROM modules/cartridges"

then we get a level playing field. The constraint as 'personal computer' is meant to restrict the answer to general purpose machines and exclude gaming and other special function devices. The 'intended' is meant that the feature was purposely built in, not later added by using an otherwise existing interface (like a bus connector) for ROM cartridges. The term 'module/cartridge' is meant to avoid haggling about the case format and naming conventions.

Now we get several candidates.


The first mass produced system with ROM cartridges is of course the Channel F of 1976 followed by the RCA Studio II in January 1977. While both being special (game) devices, they established the idea of ROM modules. It becomes more interesting when looking at the follow ups Bally Home Library Computer, later to be known as Bally Astrocade and Atari VCS as both where available in a configuration that put them into (somewhat meager) home computers running BASIC. Here the Bally's BASIC setup predates the Atari.

'Real' Computers

1977-79 is also when 'real' computers where presented with an ability or even the necessity to use ROM cartridges

The most remarkable here might be the TI, as it whole system design was built around the idea of cartridges. For software (herecalled Solid State Modules/Software), as well as for hardware with it's chaining expansion Modules. It would be fair to call it the bonfire of the cartridge age.


One problem with this list is that it's only made up from machines sold primary in the US market. There have been more outside the US and it might take some additional research here.

  • I was an Exidy Sorcerer owner and we were told it was the first home computer with a cartridge (and was the answer I was expecting) but the link you have given to the VideoBrain by Umtech is certainly compelling evidence this was not the case - Thx – jwzumwalt Jul 1 '18 at 13:47
  • Arguably the first mass-produced system with ROM carts is the Magnavox Odyssey. The carts were simply a set of connected or not traces fulfilling the same function as a set of 16 switches on the original "Brown Box", and so were effectively 16 bits of ROM used to configure the system. – Curt J. Sampson Jul 22 at 7:01

See Rediscovering History’s Lost First Female Video Game Designer wherein

Forty years ago, consumer electronics giant RCA released the Studio II, a programmable video game console that, along with the Fairchild Channel F, pioneered the use of ROM cartridges as interchangeable game media.

Reading through the article you'll find the first of the games were delivered in August 1976. The RCA Studio II apparently missed the Christmas season in 1976 and sold from January 1977 through early 1978 (too low resolution and likely a bit slow for the 1978-79 season, a product that had missed it's market window).

I remember seeing ads for RCA 1802 CPUs for $1.80 likely as a result of the product collapse, distributors inundated with data books to give away.

(I had seen this question last week and reminisced over the Exidy Sorcerer's 8 track cartridge ROM conversions (circa 1978). I stumbled across this researching the COSMAC VIP and CHIP-8 today).

  • Don't be in a hurry to upvote. It was a game console not a home computer. – user9041 Sep 17 '18 at 6:13

This question is difficult to answer, because "external" and "home computer" are more or less incidental: There were PROM cards used e.g. for BASIC for example for the Altair 8800 as S-100 bus card (about 1975).

Now one could argue if the Altair 8800 was a "home computer", and if an additional piece of hardware was "external" if the connector is inside that enclosure that makes up the computer, even if it can be opened up easily, but taking the same principle and applying it to "real" home computers and moving the connector to the outside of the box that represents the computer isn't that much intellectual effort.

And even before "home computers", (P)ROM cards where used.

So this (like many things) is a continuous development of a single idea, and it's difficult to say which was "first".

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    "...S-100 bus card" - not a cartridge, not external. Also calling the Altair 8800 a 'home computer' is a stretch en.wikipedia.org/wiki/Home_computer – Bruce Abbott Jul 1 '18 at 8:48
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    @BruceAbbott What is the difference between a card and a cartridge - beside the application of a cheap plasic cover (which several S100-card) did feature? Also, the Altair does quite well fit the definition used in the Wiki article you cite. – Raffzahn Jul 1 '18 at 9:26
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    @BruceAbbott: I picked this example in particular to show that "first" and "cartridge/external/home computer" don't make a lot of sense in combination - the idea was used well before "real" home computers, and before "external cartridges" (why is something in some housing that you plug in from the outside so different from similar hardware with no housing, that you plug in into something more in the interior?) – dirkt Jul 1 '18 at 10:33

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