The Dartmouth Time Sharing System and Time Sharing The History of Computing

DTSS, or The Dartmouth Time Sharing System, began at Dartmouth College in 1963. That was the same year Project MAC started at MIT, which is where we got Multics, which inspired Unix. Both contributed in their own way to the rise of the Time Sharing movement, an era in computing when people logged into computers over teletype devices and ran computing tasks - treating the large mainframes of the era like a utility.
The notion had been kicking around in 1959 but then John McCarthy at MIT started a project on an IBM 704 mainframe. And PLATO was doing something similar over at the University of Illinois, Champaign-Urbana. 1959 is also when John Kemeny and Thomas Kurtz at Dartmouth College bought Librascope General Purpose computer, then being made in partnership with the Royal Typewriter Company and Librascope - whichwould later be sold off to Lockheed Martin.
Librascope had Stan Frankel - who had worked on both the Manhattan Project and the ENIAC. And he architected the LGP-30 in 1956, which ended up at Dartmouth. At this point, the computer looked like a desk with a built-in typewriter.
Kurtz had four students that were trying to program in ALGOL 58. And they ended up writing a language called DOPE in the early 60s. But they wanted everyone on campus to have access to computing - and John McCarthy said why not try this new time sharing concept. So they went to the National Science Foundation and got funding for a new computer, which to the chagrin of the local IBM salesman, ended up being a GE-225.
This baby was transistorized. It sported 10,0000 transistors and double that number of diodes. It could do floating-point arithmetic, used a 20-bit word, and came with 186,000 magnetic cores for memory. It was so space aged that one of the developers, Arnold Spielberg, would father one of the greatest film directors of all time. Likely straight out of those diodes.
Dartmouth also picked up a front-end processor called a DATANET-30 from GE. This only had an 18-bit word size but could do 4k to 16k words and supported hooking up 128 terminals that could transfer data to and from the system at 3,000 bits a second using the Bell 103 modem. Security wasn’t a thing yet, so these things had direct memory access to the 225, which was a 235 by the time they received the computer.
They got to work in 1963, installing the equipment and writing the code. The DATANET-30 received commands from the terminals and routed them to the mainframe. They scanned for commands 110 times per second from the terminals and ran them when the return key was pressed on a terminal. If the return key was a command they queued it up to run, taking into account routine tasks the computer might be doing in the background.
Keep in mind, the actual CPU was only doing one task at a time, but it seemed like it was multi-tasking! Another aspect of democratizing computing across campus was to write a language that was more approachable than a language like Algol. And so they released BASIC in 1964, picking up where DOPE left off, and picking up a more marketable name.
Here we saw a dozen undergraduates develop a language that was as approachable as the name implies. Some of the students went to Phoenix, where the GE computers were built. And the powers at GE saw the future.
After seeing what Dartmouth had done, GE ended up packaging the DATANET-30 and GE-235 as one machine, which they marketed as the GE-265 the next year. And here we got the first commercially viable time-sharing system, which started a movement. One so successful that GE decided to get out of making computers and focus instead on selling access to time sharing systems. By 1968 they actually ended up shooting up to 40% of the market of the day.
Dartmouth picked up a GE Mark II in 1966 and got to work on DTSS version 2. Here, they added some of the concepts coming out of the Multics project that was part of Project MAC at MIT and built on previous experiences. They added pipes and communication f