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IBMWatson autobiographythoughts on 767


John R. Levine

IBMWatson autobiographythoughts on 769
Charlie Gibbs Easy and hard are relative and depend on the overall context. For example, there may be math formula that's...

basically leases were somewhat like cellphone billing ... basic plan and possibly a lot for overages ... based on cpu meter.

the meter ran while the processor wasn't in wait state and-or when the channels were active.

one of the things that enabled 7x24 time-sharing service cp67 was the conversion to "prepare" command for telephone lines. typically timesharing users were billed for cpu time used ... but the datacenter was billed for the cpu meter running (which could also run when the processor was idle ... but the channel was active). the prepare command to terminal controller ... basically told the controller to wait for input from the terminal ... but disconnect from the channel. prior to having the "prepare" command in the channel program ... the channel ran just waiting for terminal input (and the cpu meter ran even if nothing else was going on).

misc. timesharing postings

IBMWatson autobiographythoughts on 768
Anne & Lynn Wheeler I presume in the early days of computing the hardware was so incredibly expensive compared to programmer wages that software cost wasn't as big as a concern...

having prepare command ... allowed service to be up & running and ready for user activity ... but otherwise have the cpu meter stop (and not incurring any leasing charges) when the system was otherwise idle (and therefor not earning any revenue from users).

the 370s still had cpu meters ... the big conversion from lease to purchase still hadn't happen.

the meter on the 370 tended to "coast" for 400milliseconds ... after everything had otherwise stopped ... aka both cpu and channels had to be idle for more than 400 milliseconds for the cpu meter to actually stop. quess which operating system had a kernel process that would wake up every 400 milliseconds?

random past cpu meter posts: IBM-PC sales proj.. IBM-PC sales proj.. performance (expansion of VTOC position) Reference Manuals Was: Movies with source code machine was it? from SGI weren't cpu metering please mainframes Microcoded


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IBMWatson autobiographythoughts on 766