Eric Plow recalls what it was like to operate computers at his job at the UNC-Chapel Hill School of Dentistry in the 1970s. He explains the capabilities of the computer and the cost associated with completing a "job," or project.
Well a computer was huge, it generated tons of heat.
A computer probably would fit in this whole room
and it would cost a million dollars.
Back then they were just amazing what they could do
but compared to what computers can do nowadays they were pretty weak,
but we didn't know that back then
so we enjoyed the computer power that we had.
But because so many people wanted to use the computer
the computer had time sharing,
so you would punch your program on a bunch of computer cards
and some of the programs would be two thousand, four thousand cards long
and you'd sit there with a card punch and punch this thing in
and if you made a mistake you'd have to throw the card away and re-punch it,
so it was very laborious.
Then whenever you wanted to run a task, or we called it a job, a computer job,
an activity, like if you wanted to compute a statistical analysis of some data
you would load the program, you would load the data on cards,
you'd bring it to the computer center, this big monster computer,
they would run the cards through a card reader
and then that job that you submitted would sit there
and it could run in five minutes or it could run in five hours or it could run ten hours from now.
You had no idea when the job would run. Once it ran you would get output from the job, printed paper.
It wouldn't display on a screen.
So you would have to sit there and-. Well, you wouldn't wait because you could be waiting there forever.
What you would usually do is go study or do something else and then come back in a few hours
and hope that your output was there.
If it wasn't you'd have to come back.
Well the frustrating thing is if you had any kind of syntactical error in your computer program, if you missed a comma or misspelled a word,
it would just reject it and give you an error message and you'd have to start all over again.
So to run a particular task could require several iterations
One of the big things that affected the cost of the job,
besides the size of the job and how much computing power you needed,
was the priority which you wanted to run,
but every time you upped the priority the cost would double
and computing back then was not cheap. If you did a simple computer job it could easily cost twenty dollars,
which even back then was a lot of money.
If you run it several times you're up to a hundred, a hundred and twenty, a hundred and fifty dollars just for one run.
So if you ran it priority one you'd be lucky to get the thing back in a few hours.
If you ran priority two it would come back maybe in an hour or two
but it would cost twice as much.
If you ran priority three it would really be expensive
but you'd get it much-well nobody had the budget to run priority three.
We usually ran priority one but our jobs at the dental school were so large and so expensive
and so time consuming that we ended up running a lot of stuff priority zero
which meant that it would only run at night.
That's the only time they would run it.
So I spent many, many nights
getting there at midnight, and usually I'd be one of three or four people at the computer center,
and back then you could sit your job in and it would come back within a few minutes
and you could correct it, put it in again, and just get a really good turnaround,
which you could not do during the day. So you ended up working a lot at night and lost a lot of sleep.