The IBM 650 was a vacuum tube based computer of the 1950s to early 1960s vintage. They were decimal arithmetic based computers with a small rotating drum memory. These were largely business computers and most often used for accounting and the like but there existed a Fortran implementation for them. The 650 was really IBM’s first successful (as in made a lot of money) computer. My connection with them is rather tenuous. Virginia Tech had one prior to my becoming involved with computing there. When I was just beginning to learn about computing they had switched to an IBM 7040 and IBM 1401. (I believe there was an IBM 1620 prior to the IBM 7040.) The IBM 1401 was largely the successor to the IBM 650 in IBM’s product line. There were still manuals, programs, and miscellaneous equipment related to the IBM 650 at Virginia Tech when I started using and working with computers there. I am very surprised that someone still had an IBM 650 outside a museum given its age.
The IBM PC and particularly the later IBM PC AT (and PS/2s ) had really well designed keyboards particularly compared to many of its competitors. I believe the explanation is the IBM had a tremendous amount of experience with typewriters (the IBM Selectric typewriters with the interchangeable spherical typeball elements (“golf ball”) were dominant in business and government offices for many years, apparently justly.) IBM also had a lot of experience in keyboards in several generations of CRT displays, 2260, 327Xs, the Displaywriter, and shortly before the IBM PC 5150 was introduced, a product called the Datamaster, a small business computer which shares some design elements with the IBM PC.
The PCs keyboard wasn’t quite perfect but it was pretty good, both in layout, and in presence of PF (Program Function) keys. A feature I think they got from the 327X CRT displays. The keyboards were solid, reliable, gave a positive tactile and audio feedback hen a key was pressed, which is important for a touch typist. The IBM PC AT introduced in 1984 improved the keyboard even more. The “enhanced” version of these keyboards were called the Model M.
The IBM PC AT changed the electrical interface so that the “AT” keyboards were not compatible with the PC/PC XT keyboard (There were some keyboards with PC/AT compatibility switch I am not sure if these were made by IBM or a 3rd party). The AT keyboard was carried over nto the PS/2 family with not much change other than changing the connector to a PS/2 mini-DIN connector. There are a large number 0f models and variants. Sometime in the process IBM spun off its typewriter (and small scale printer) division located in Lexington Kentucky, which became a company called Lexmark. Many Model M variants were made by Lexmark over the years, eventually the keyboard business was sold to a company called Unicomp which continued to make variants of the Model M. The Model M keyboards are still sought after today by cognoscenti and people who keyboard a lot, because of their superior typing characteristics and reliability. Model M keyboards appear fairly frequently on Ebay because of this demand. I am typing this on a 20 year old Model M Part No 1391401 made Nov 24, 1987 (It’s hooked to a keyboad video mouse (KVM) switch box and I use it on 4 different computers, none of them made by IBM.) For some people the presence of a good keyboard was an important selling point for the IBM PC and successors over their competition.
The first “Personal Computer” I had was the IBM PC 5150, though I had worked with “mini” computers before such as the PDP 5, (yes the PDP-5 a predecessor to the PDP-8), the PDP-8, and PDP-11, and played with the IBM 5100 computer, primarily the APL version. I also read the famous Popular Electronics MITS Altair issue and followed the S100 bus machines and then the Apple II PC, read Byte etc but I didn’t purchase one as the main frames had more allure. IBM announced the 5150 PC in August of 1981, and shortly there after I saw a presentation and demonstration at a IBM user group meeting (SHARE) in I believe Chicago. I was so impressed that I attended the demonstration and question and answer session twice (it was scheduled multiple times), I believe that several of the original developers were present. There were several software options announced including a version of CPM. (Despite the famaous story of Digital Research taking the IBM nondisclosure agreement and changing IBM to Digital Research and “disclosee or whatever” to IBM and IBM refusing to sign). IBM announced a CPM-86 version with the IBM PC, and also the UCSD D-PASCAL system in addition to PC-DOS. I wish I could say immediately recognized that DOS was the way to go, but that was not the case. However to me, it was clear the hardware was a winner but it wasn’t clear to me which operating environment was going to prevail. If I remember correctly DOS was by far the cheaper of the three and I suspect that had as much or more to do with its eventual dominance than anything else. One feature about the IBM PC 5150 that impressed me was the nominal 1 Megabyte address space. True, as it later became clear only 640K (or perhaps somewhat more) was user usable. For the time this was an impressive amount of memory and the major thing I found lacking in most if not all of the then existing personal computers. For comparison the IBM 370/155 mainframe had a maximum physically installable RAM of two million bytes.
This is a blog dedicated to random observations on computing, computers (Vintage IBM or otherwise), Life, the Universe and everything to do with technology (with apologies to Douglas Adams).