vbc...@gmail.com (Vince Coen) writes: > A M/F may not break down CPU time between system and the application > depending on O/S used.
as undergraduate in the 60s, I remember rewritting some CP/67 (precursor to vm370) so that it world accurately account for all time. More than a decade later I saw code in unix that was similar to the 60s cp/67 code. I conjectured that was because some of the CTSS people had gone to the 5th flr to work on multics and others had gone to the ibm science center on the 4th flr and did cp/40-cms, cp/67-cms, invented GML, bunch of online stuff, etc. Folklore that the people that had originally done Unix had previously been working on Multics and "Unix" is a play on simplified Multics. About the time I encountered the Unix code ... MVS was claiming that unaccounted (cpu) time could easily be 50-60% aka "capture ratio", they calculated wallclock cpu "wait" time, so the inverse was wallclock cpu use, "capture ratio" was the accounted for cpu divided by (wallclock elapsed time minus wait time). This showed up when internal datacenters were bursting at the seams with largest POK mainframes ... and were looking at offloading lots of the MVS workload to distributed 4341s out in departmental areas ... and were not correctly taking into account "capture ratio". Some of these very large MVS applications weren't able to run on vm/370-cms. The issue was that the original os/360 system services simulation was only 64kbytes ... and a much more complete implementation somehow got lost when head of POK convinced corporate to kill vm370 product in the mid-70s (and transfer the people to work on MVS/XA) ... Endicott did eventually manage to resurrect the VM370 product administration ... but had to reconstitute a group from scratch. as referenced in this old email (discussing "capture ratio" and other things) ... it only took another 12kbytes of system services simulation to get the MVS applications into VM/370-CMS production http://www.garlic.com/~lynn/2006v.html#email800717 -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
