[RndTbl] How much did one second of computer time cost in 1975?

Brian Lowe brian2 at groupbcl.ca
Mon Oct 25 20:56:07 CDT 2021

Hello all,

Today with multi-core CPUs running at gigahertz speeds attached to gigabytes 
of RAM and terabytes of disc space, we're well used to running programs that 
require what would be enormous resources back when mainframes ruled the data 

My question is "how much did one second of computer time cost in 1975?" This 
assumes the program in question is being run on a mainframe from IBM or any of 
the other manufacturers of the day. Of course, there are a lot of factors to 
consider: leasing costs, staffing, power and cooling, if the system could run 
more than one program simultaneously, and how computer time was charged back 
to the users.

I'm interested to know if anyone on this list has had experience with this 
sort of system accounting, and if they can recall some numbers.


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