There is plenty of information on the technology of machines like the VAX, PDPs, 360 etc. Quite a bit also on how they were built. ('The Mythical Man-Month' and 'The Soul of a New Machine' are generally recognized as classics. A lesser-known favorite of mine: 'The Supermen'.) But not so much on how they were used, particularly at the 'coal face' level, so to speak.
This post was inspired by a comment on https://news.ycombinator.com/item?id=45818471
"... at the time I was working on an IBM 360, mostly doing Fortran for scientists running anemometer simulations. The center for this activity was the person in charge of the 360 who could dole out time on the computer.
The power dynamic was something I did not really notice, but in retrospect this was frustrating for the mathematicians/scientist trying to run simulations. They had to queue up and wait.
Then one day a mathematician brought in an Apple II running VisiCalc. His own personal computer. He ran his simulations on that."
One thing I found fascinating here: looking at the clock speeds of 1970s computers, by today's standards, you would expect 'the computer is too slow' to be a big limiting factor. But in the above account, it wasn't. The actual workload was such that an Apple II running VisiCalc was good enough to get the job done. The limiting factors were the actual availability of the 360 (presumably there genuinely was not enough machine time to go around), and the overhead of dealing with the politics of gaining access to it.
What were people's experiences with minicomputers and mainframes? What did they enable, that was more difficult or impossible than before? What were the actual bottlenecks and limiting factors? I'm interested in both direct firsthand accounts, and links to published material in any format.
PaulHoule•3mo ago
I really enjoying using a PDP-11 with RSTS/E, here each user got two 64k address spaces, one for data, one for code, so you got a BASIC experience that was a bit better than the Apple ][ or TRS-80, particularly you could save you work on a hard drive.
In the computer explorers I got to use an IBM 3090 in the later 1980s which was close to the pinnacle of bipolar mainframes running the 370 XA architecture. At this point in time the IBM Mainframes had
https://en.wikipedia.org/wiki/VM_(operating_system)
IBM really struggled to develop timesharing for the 360 and wound up applying virtual machine technology to give every software developer their own copy of a DOS-like operating system. In the early 1970 it was really a struggle to get time on a 360, by the late 1980s VM was everywhere and you could just log in with your 3270 terminal when you wanted to.
Circa 1980 it was easy for a microcomputer user to "look up" to the PDP-11 and think the future might look like that but actually the PDP-11 became obsolete rather quickly because the user had access to only 64k which was the same problem micros were about to have as memory got cheap and you could afford more than 64k of RAM. Digital came out with the VAX which was basically a modern computer, my high school got one by the late 1980s and it was a really capable on machine where you had good compilers for languages like PASCAL which was great for CS education.