The IBM 5100 was a portable data-processing workstation available in 1975, which was based on the 1973 IBM SCAMP project [video]. This included a tape cassette storage, up to 64KB RAM, supported both BASIC and APL programming, with an integrated 5″ CRT screen and keyboard. This was all available in 1975, the same year as the Altair 8800 kit. While the Altair kit was around $500 (with no keyboard or monitor or storage device and no built-in software), the IBM 5100 was priced about $10,000 (in 1975 dollars for base-configuration) as a ready-to-go product with a large suite of software (additional options increased the system cost to a max configuration of about $20,000).

In 1978, IBM released an updated version called the IBM 5110. Essentially the same “A1″ motherboard, PALM processor, power supply, and 5″ screen as the 5100 were used. The base price of the 5110 remained around $9,500. One cosmetic difference was that the 5110 has a black front face around the keyboard, whereas the 5100 has white. An 8” disk drive was available for the IBM 5110, and both BASIC and APL had extended capabilities (for instance, BASIC now supported a “FORMS” keyboard for quickly preparing interactive data entry forms).

Was the IBM 5100 the first Personal Computer?

The short answer is No. But it’s not quite that simple.

There is plenty to debate on whether the IBM 5100 or IBM 5110 are still yet in the category of a personal computer. The IBM 5100 decal label states “Portable Computer” but those words are removed on the IBM 5110 decal label.

Could the IBM 5100/5110 be “personally owned”? Barely.

Could the IBM 5100/5110 be “personally operated”? Certainly.

There is a broad spectrum between the DEC PDP-1 of 1960 up to the IBM 5150 PC of 1981 that have been proposed as the “first” Personal Computer. And all these honorable mentions are generally valid at being the first at some kind of innovation along the way towards what became the Personal Computer.

(click image below for further details on my mural of personal to home computers)

Based on the above mural, the IBM 5100 is in a “hybrid” middle ground between minicomputers and what became microcomputers and then “true” personal computers. The IBM 5100 is the “last of a kind” of pre-microprocessor systems. But to be fair, there is a lot of context information to be mentioned in those formative years of 1970-1974:

  • The “idea” of a personal computer was certainly “in the air” by 1970. As the Space Race began winding down, the technical know-how in electronics would spread to the next generation of pioneering engineers.
  • The “great” IBM antitrust case started in May 1975 (related to the Sherman Act). While eventually dismissed in 1982, this made IBM hesitant to market these new products. A similar accusation of “bundling” hit Microsoft in the 1990s (with I.E. and Windows).
  • The “industry standard” was that computers were leased, not owned. No one yet imagined what a personal computer could even be used for. Sort of like the idea of selling a steam locomotive to home users: what could anyone possibly do with such a thing? (it took decades to “miniaturize” pistons and develop the method of using gasoline to reliably drive them — resulting in automobiles)
  • In these early years, TTL or discrete component processors were still faster than the very early microprocessors.
  • The DP 2200 was a great system, but still expensive and niche (with an unreliable power supply). The Wang 2200 also had similar power supply issues (their initial released used a large “external” power supply). That is, switching-power supplies on a small scale were still a technical challenge in these early days. Few of these pre-1973 systems still function today, while in comparison the IBM 5100 has a fairly reliable internal power supply.
  • The base Altair 8800 had very little utility (similar to the KINBAK-1, it could just blink lights). But the Altair could be expanded. Adding ROM cards, async IO cards, 4K memory, a kind of serial CRT, tape drive, and BASIC or some programming support — a fully kitted Altair could quickly approach $5000 (see prices at the end of the Altair manual). From this perspective, the IBM 5100 base price isn’t so unreasonable.

NOTE: OldComputers.Net (here) is an excellent archive of many personal computers since 1970.

The IBM 5100 was one of several early personal computer systems. It would be ordered from IBM and cost about as much as a very nice car, but less than a house at the time of its production. Once the IBM 5100 arrived, it was fully functional as a personal computer – to program whatever you desired, without having to remote to any mainframe. It had a multi-line screen, full size keyboard, tape storage, a decent amount of RAM (8K to 64K) and could run some existing IBM System/370 or IBM System/3 software (since it incorporated the APL or BASIC of those systems).

The Wang 2200 of 1973 was probably the most equally capable system of that time (and there is a story that a Wang 2200 was rolled into an IBM VP’s office, as proof that the concept of a microcomputer was possible). The main difference is the Wang had an external PSU and processor, making it a far less portable system (and the Wang had their own BASIC, which had some quirks due to how it was implemented). But the Wang 2200 had a larger screen and was very effective as a desktop publishing system.

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