What was the first commercially available computer that could be purchased by individuals? When did it come out? Video game consoles do count, as do DIY kits.
The Altair!
There are various answers to this but I think best contenders are the Radio Shack TRS-80 and the Apple II (later followed up by the even more successful Apple IIE) that were introduced in 1977. They saw moderately widespread adoption (there was a decent chance someone you knew actually had one if you lived in a non-poor neighborhood) and they were recognizable as personal computers.
You could buy some pre-assembled computers before that but they were mainly for business or hobbyist use and they tended to be really expensive even in constant dollar terms.
It wasn’t until 1982 that the home computer market exploded with the Commodore 64(still one of the best selling PC models of all time). The IBM Personal Computer (where the term ‘PC’ comes from) was introduced a year earlier in 1981 and was hitting its stride on the home and office market around the same time. The original Apple Macintosh debuted during one of the most famous Superbowl commercials of all time in 1984 and was an instant hit as one of the first, widely available, easy to use personal computers.
There is a long list of also ran’s and almost did’s but those were most important models of the early PC market.
The Computer History Museum and the American Computer Museum consider the Kenbak-1 to be the first personal computer.
More, from the Computer Museum of Nova Scotia, which shares this view.
Main home page, by its inventor, John Blankenbaker.
The Altair 8800 was the first influential personal computer, the first personal computer which spawned imitators and a software industry around it, and which had an impact on later designs, not least of which was the IBM PC, which took many cues from the S-100 bus computers of which the Altair 8800 was the first. However, it wasn’t quite the first personal computer.
Honeywell Kitchen Computer (aka 316)
I can do better than that. How about the Antikythera mechanism from 100 BC. It was a fully functional analog computer. Early calculators were too. The term ‘computer’ just means something or someone that does complex mathematical calculations and it used to be a literal job title (typically filled by women). The problem with this question is that it is not well defined. An individual could have bought an Eniac in the 1940’s if they had enough money and wanted to badly enough (and it would have taken a whole lot of money).
Early video game consoles like Pong were available by 1972 and electronic calculators were around in the 1960’s (although very expensive). Those are technically ‘computers’ as well.
I interpreted the question to mean what was the earliest successful example of computers that are still recognizable as a true PC.
No evidence those were sold, to my knowledge. The Kenbak-1 was at least a real system people bought.
By that measure, you could say rocks were the first computers, and, therefore, the first home computers.
A better interpretation is the first all-electronic stored-program computer which was priced in the reach of individuals who weren’t Fortune 500 CEOs. That takes the Kitchen Computer out of the running, seeing as how it cost $10,000 in 1969, and almost $80,000 today.
NERDS!
The first computer I worked on ran on paper tape. :o
Plenty of Honeywell 316 computers were sold. They were a real commercial system. Whether Neumann Marcus managed to sell any to home buyers is another matter. But they were available for sale, so they meet the OP’s terms.
Back then there were not so many rich geeks. But, I’m sure IBM would have been pleased to sell anyone a 650 or later a 1400 series had they the money. Whether any rich geeks bought home PDP-8s or similar I have no idea. The question is rubbery.
Slide Rule
Nonsense!
The paper tape was just an input/output mechanism. Probably input -only, actually, and liklely an accessory to something like an Model 33 Teletype.
The paper tape wasn’t even an integral part of the computer, much less something that the computer ran on.
Hewlett Packard programmable calculators were true computers, in that you could program them, and they could actually do useful things. They came on the market from about 1975.
I still have fond memories of the HP 29C, which introduced introduced me to programming.
The Colossi ran on paper tape.
http://www.colossus-computer.com/colossus1.html
Somehow I doubt there are many people alive that can claim to have worked with one.
HP 25 here. The 29C was a sweet little thing. But the 25 saw me though high school and uni. Still have it. Can drive the keys without looking even now.
You’re only a True Nerd if you’ve watched the reaction of a programer dropping their box of IBM cards.
but only sold to about 100 units,
and perhaps ended because that was the market for a prototype sort of thing with a useless amount of RAM. Like a lemon with two pieces of metal in it does make electricity, but isn’t really a useful voltaic cell.
Its all happening in 1977, Apple ][ released in June, TRS80 released in August, Commodore PET October.
Apple were in a rush and commissioned Microsoft to produce the Basic interpreter’s ROM. The Apple ]['s would be sold with a ROM chip labelled Copyright Microsoft.
There is a trick I used for any program that was of length. With a marker I drew diagonal lines across the deck. One long diagonal line from corner to corner of the entire deck, and then a set of steep lines all along the deck. This mean that once the cards were all upright, it was easy to shuffle them back into order, as each had a unique and visually easy to sort marking. (This is hardly an original idea.)
Luckily I was only on cards for a couple of years, and any truly serious programming was done on proper interactive systems.
Some of this depends on how you define “widely” available. While other computers were available earlier, the TRS-80 was the first one I saw being used in homes in any numbers. The Apple II came after that, followed by the Commodore 64. Then came the war of the 8-bit computers.
I had some experience with earlier computers like the Commodore Pet, but while they weren’t exactly unknown at the time, I wouldn’t really consider them to be widely available.
By the way, for those of you who never had the experience of using one, the chicklet keyboard on the Commodore Pet was an absolute piece of misery. I hated that damned thing.
You could also physically break a Pet simply by repeatedly writing to the same location in video memory. The chip would overheat and pop.
The Commodore 64 also had one of the worst data storage designs I have ever had the misery of working with. The data cassette would store each program twice, and when you loaded the program it would compare both copies. If they didn’t match, the load failed. So it took twice as long and was half as reliable. Checksums and parity checks were well known at the time, so there was no excuse for that.
The first thing that the Commodore 1541 disk drive did when you turned it on was it slammed the disk head all the way to the side so that it could figure out exactly where it was (it kinda self-aligned itself that way too). Gave it a rather distinct sound when you powered it up. 170k of storage (yes, k). Wheee!
Ah, the good old days…
1977 was a watershed year for home computing becoming a mainstream thing, but not for the existence of home computers. The first S-100 bus computers existed prior to that, but, as people have mentioned, most of those were kit systems and not sold pre-assembled, and they were explicitly targeted to the HAM radio and electronics geek set. Even the Apple 1, now a rare collector’s piece, was sold in kit form.
They were also sold to businesses, and aped business minicomputers in multiple ways, from requiring text terminals in order to use to the CP/M operating system, as influenced as it was by the OSes DEC was making for the smaller minicomputers of the period.
Micro-Soft made its first big splash selling a BASIC interpreter for S-100 bus systems. Gates wrote that code on a DARPA-funded (that is, tax-funded) PDP-10 mainframe he had access to at Harvard, so his turning around and selling it was… questionable, morally and perhaps legally, and makes the snit fit he threw about the hobbyist community copying and trading his software all the more precious. I mean, they were copying and trading all the other software, but Micro-Soft was special, and if they didn’t see that, well, they were just great big meanie-heads!
Ah, but I digress. 1977 marked a division in home computing, between the game-centric home systems, most of them built around the 6502 CPU and running a ROM BASIC interpreter as an OS, and the business systems built around the 8080 or, later, the Z80 CPUs, which universally ran CP/M. This dichotomy would be closed again when the IBM PC was introduced, even though IBM itself would attempt to re-open it by making the IBM PC Jr.
Huh. I didn’t know Woz worked for Microsoft. 
(The original BASIC in Apple II computers was Integer BASIC, written by Wozniak. Apple didn’t license Applesoft BASIC from Microsoft until a bit later.)