Hello Kurt!
Wednesday March 08 2023 06:44, you wrote to Fabio Bizzi:
Fabio Bizzi wrote to Vincent Coen <=-
But IMHO, as I wrote to Ward, Before IBM 360 it's hard to find a
"real" mainframe, moreover the IBM AS/400 and it's predecessors
System 36, AS/38 etc. are all dipartimentals. You're right on 370
ad Amdahl, I forgot them. :D
Dipartmentals is a new term to me. We called S/36, S/38 and AS/400es Midrange computers back when I was working on them.
The Computer History Museum in Mountain View, CA has a working IBM
1401 that they IPL for visitors - https://computerhistory.org/exhibits/ibm1401/
My son was 13 when he got to watch it and realized how much has
changed by counting how many people it took to run the thing.
They must have been non operators in their working lives.
I worked as an operator for the 1401 on two sites where on one it is also used to feed a 7094 and this had around 16 tape drives.
Both 1401's had only tape drives for mass storage with a 1403 line printer of 600 lpm, card reader 1k - 2k pm and possibly a card punch but do not recall one.
In all instances I worked alone.
Remember the 1401 was a one job at a time system so feeding punched card and loading the tape decks for each job and when completed removing printed o/p and
placing it in a tray along with the card box where it was collected by the job submitter was hardly hard work.
Seem to recall starting around 9:00 in the morning and finished around 18:00 and some times a little later Monday through Friday.
The second site I could work just the weekends on a 12 hour shift for double pay at 8 pounds sterling (this was around 1961 - 1967. This was when it was 4.80 dollars to 1 pound - when a pounds was worth something (it is now around 1.20 to the pound.
Bye the bye all these were classed as Mainframes whether only doing one job at a time or many and here a mainframe was a little bit based on size and all ran as three phase power.
Many mini's if not most all peripherals were single phase i.e., 240 volt in the
UK as I know well as I bought in the mid 70's, a old DEC 8 and a 11 for use at home and these were marketed as key edit systems (in place of using punched cards or tape).
I used these in a upstairs spare room in my first (terraced) house both in the same room but admittedly not all components installed but the most useful peripheral was the teletype 33 that had a paper tape punch and reader which I also used as input to one of two, the very first micro computer boards made using cpu's of a 6502 and a 4040 then a 8080.
It was a lot of effort to get each part up the stairs as they did weigh a fair bit.
From 65 I was also working as a programmer in Cobol and assembler (including macro assembly) but still did some operating if the operator was ill or just not available, even more so if I had compile needed and the operator had finished for the day and yes as a programmer unpaid overtime was the norm.
After that was working on 360's and ICT 1900 series that had operating system that could run more than one task at a time so the work load was higher and even more so on later spec'd 360's and 1900's. During this time I also worked with their other kit which included URE's and what is now called mid range but then was called mini's sometimes at the same time moving from one room to another where these rooms could be large.
For the 360/70 they could take up a room the size of a football (soccer) field and the best tool to have was roller skates to get around quicker but these also included hard drives with removable disks around 30 inches in diameter
and 10 or so platters but small capacity to today's standards of around 10 -
50 MB and these came in a protective case so you had to remove them before opening the drive lid (may be) and twisting it into the drive to lock it in before closing lid and pressing power up, then load buttons etc.
For these systems there could be anything from two to 5 operators working per shift of 8 hours or so where some operators would be responsible for say loading tape decks or loading disk drives and others loading card readers and unloading line printers etc and this was when printer could produce 2k lpm or more. This printer used continuous paper in boxes of 2,000 sheets in widths ranging from (in columns) of 120, 132, 160 and some times 80 (for letters
etc)
So in a nut shell working a small computer such as a 1401 or low end 360 one operator can easily handle running it alone.
Note that when starting up a IBM 1401 in the morning the basic task was to manually load up the machine code by flipping switches and pressing run which in turn would load a executable card pack or load from a tape drive.
I do remember a a few weeks of this process I created a boot strap program that
I could load on a card reader that processed a tape desk containing a basic operating system and I do mean basic.
One interesting aspect of the IBM 7094 which was in a room facing the road via large windows which had a large foot traffic at night was a switch that would unload ALL of the tape decks at once as entertainment for these window
watchers - another switch / button could if all the drive had a tape threaded in would load them all at the same time but not so interesting to watch :)
If you loaded a some executable to override the original program in the 7074 you could play some variations on what desk did what and when to make it more entertaining - helped while the hours late at night :)
What do you want, the pay was low for an operator, but compared to most other jobs it paid a lot more !
Programming made up for it was the pay was a lot, lot more.
Remember this was in the early to mid 60's.
Vincent
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