The Honeywell 1640 was the first computer I used to any significant extent. I know almost nothing about the machine.
My high school, Detroit Catholic Central, had a dial-up account that allowed us unlimited use of the machine by one user, 12 hours a day, 6am-6pm. I believe we were charged $2000/year for this account. (Evenings and weekends cost extra--weird, huh?) We dialed a local telephone number with our trustly Teletype ASR 33, which somehow connected us to the computer, which was located in Minneapolis.
When I was a sophomore in 1972, a chemistry science fair project prompted me to seek help on computerizing some spectrophotometric calculations. (See GE 635). At the suggestion of the computer instructor, an upperclassman named Jim Lisius wrote some simple FORTRAN programs to my specifications. (Very nice of him, since he didn't know me from Adam.)
I was advised to break down the job the programs would have to do into very small steps. This point was made repeatedly to me; the teacher didn't realize how very simple the tasks were: just evaluating a few simple formulas. Knowing very little about programming, I would up essentially writing the specs in pseudo-assembler language. The specs were longer than the final code. The programs were simple enough that I believe Lisius had little problem getting them working. The main concern was his desire to get the FORMAT statements just right so the output would look good. That was that for the school year.
That summer, my parents bought me a book from Hudson's annual technical book sale, a FORTRAN text entitled FORTRAN II & IV Programming. It was a lousy book, but I did learn FORTRAN from it. I even wrote some programs--staying away from arrays, which I didn't really understand--even though I had no machine on which I could run them.
When school started in Fall 1972, I signed up for the "Computer I" class, mostly to get access to the computer. In addition to the single on-line ASR 33, we had a second, off-line Teletype that could be used to create and edit paper tapes. I got pretty good at typing in my programs off-line. If you made a mistake, you backspaced over the mistake and punched a Rubout (ASCII DEL, 0x7f, all ones) over it. The Honeywell system ignored any Rubouts it was sent interactively. Egregious errors could be corrected by selectively copying the good parts of the tape to a new tape.
I'd guess there were about 80 (?) people taking the course, but surprisingly, the single ASR 33 (10 characters per second) did a pretty good job of servicing the needs of all those people. There was a signup sheet for on-line time, divided into blocks of perhaps half an hour. You signed up for time in advance, often several days in advance.
A few of us took to hanging around the Teletype, taking turns at using the free timeslots. It was hanging around the Teletype after school hours that I first learned that "just a few more minutes" means something different to a programmer in the throes of debugging or development than it does to ordinary people. I'm ashamed to think of how, on a few occasions, I made my ride wait "just a few minutes" while I tracked down one last bug.
I think that the H 1640 was a modest machine. I know that our programs were limited to very small amounts of memory. In the early going, I somehow got the idea that the way of writing a program was to read all the data into an array, process the data, and then print out the results. I did this even if I were just adding a bunch of numbers. I remember having to reduce my array sizes to 25 elements just to get my programs' memory requirements low enough to be able to load.
I assume there were other timesharing users of the 1640, but I was not aware of them. To my knowledge, we never found the equivalent of the UNIX "who" or "write" commands.
My interests in those days were mostly programming language-oriented, and I didn't care much about the operating system or utilities. I read all I could about FORTRAN and its many dialects. A fellow student named Chris Murphy learned BASIC and Extended BASIC. Ironically, these simple, not-very-powerful languages were "hacker's" languages, because the language everyone knew was FORTRAN. Chris also learned TEACH, a very simple language for developing computer-aided instructional programs.
Most people stored their programs on paper tape. The school did have access to a very limited amount of disk storage. An upperclassman whose name I forget was in charge of handing it out. Most people didn't get any disk space; I guess only the people he liked got any. His approach was to create many one-block files, each protected by a password. He created enough files to fill our disk quota. When he decided to give some filespace to a person, he'd tell the guy the filename and password. The happy recipient of the filespace would use the password to delete the file, freeing one block of diskspace, and then create his own file in that space.
Once, this sysadmin forgot the password to a file. He told us all the filename and as much of the password as he could remember. Several of us wasted quite a bit of time trying to guess the password. We never succeeded, as far as I remember. I wonder how many people would expend that much effort nowadays for 4096 bytes of disk?