History records August 12, 1981 as the day IBM changed the computer industry forever by unveiling its first PC. But that machine’s official model number was 5150–marking it as a conceptual descendant of the IBM 5100 Portable Computer, which was announced in September 1975.
Back then, the PC industry just barely existed, having been kickstarted earlier in the year by MITS’s introduction of the Altair. But while the Altair was a do-it-yourself kit aimed at hobbyists, the IBM Portable was a piece of business machinery designed to be plug-and-play, at least by the standard of the era. Here it is being advertised on Face the Nation—apparently in 1977–and shown performing useful work everywhere from an insurance office to a dairy farm.
The 5100 had a 5″ screen—which might be smaller than the one on your smartphone—and loaded programs off jumbo-size tape cartridges. When the ad says that the computer weighs about 50 pounds, that’s supposed to be impressively light; after all, IBM was known at the time for room-filling mainframes. “You can plug it in anywhere” is also a boast, since it wasn’t yet a given that you could simply power a computer off garden-variety power. (It didn’t run off a battery, which was fine, since nobody would have expected any computer to do that.)
In what’s presumably an attempt to avoid sticker shock, the commercial says that the 5100’s price is “reasonable,” but doesn’t state it. The system started at about $9,000 and cost $20,000 fully decked out–not cheap, even for the era, but also not bizarrely high.
The IBM 5100 stayed on the market until 1982, when it must have felt like a bit of an antique. IBM then developed a festering reputation for not being very good at designing portable computers—a burden it shook off only a decade later when it introduced its first ThinkPad.