The following message is a courtesy copy of an article that has been posted to alt.folklore.computers,bit.listserv.ibm-main as well.
re: http://www.garlic.com/~lynn/2007m.html#64 Operating systems are old and busted http://www.garlic.com/~lynn/2007m.html#66 Off Topic But Concept should be Known To All http://www.garlic.com/~lynn/2007m.html#67 Operating systems are old and busted part of the timesharing issue was whether the off-shift useage charges (or just plain useage) could justify the off-shift operational costs ... since useage tended to decline significantly offshift and weekends (although I finally got my home machine for dial-up access mar70 ... it was 2741 selectric, and have effectively had online access at home ever since). lots of past posts about timesharing services ... including commercial (cp67 & vm370) timesharing service bureaus in the 60s & 70s. http://www.garlic.com/~lynn/subtopic.html#timeshare in the 60s & thru some of the 70s, machines tended to be leased ... and there was system meter ... which would rackup charges as the machine was used ... even when the machine was in "wait" state ... but I/O was active. The 2702 "prepare" command was mechanism to leave the terminal lines "prepared" for any terminal operation ... w/o actually having an active I/O apparent to the system meter. the incremental machine lease charges and costs having people/operators present ... was one of the inhibitors for justifying/providing around-the-clock, 7x24 timesharing operation (since offshift useage could be extremely spotty). eliminating system meter running ... when the system wasn't actually doing anything (just available for doing something) ... and being able to run with dark-room, unattended operation ... would significantly lower the off-shift useage threashold that was necessary to justify leaving the system up, available and operational (significantly helped in transition for providing production around-the-clock, 7x24 operation). ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
