Paul Gilmartin's: <begin snippet> It would seem to me that when the time came to convert from 3330 to 3350 (e.g.), the simple path would have been to replace "TRK" with "13030" (CYL slightly more complicated) and leave the other numbers unchanged. JCL so modified would work on either model during the transition, and be suitable for any future DASD. </end snippet>
is not really wrongheaded. It is an unfortunate oversimplification for real DASD. For them BLKSIZE= values could not be ignored. If they were in moving, for example, from 3350s to 3390s, it was possible, indeed easy, to waste 30+ percent of the new devices' capacity. As I have already had occasion to note today, accurate DASD-capacity calculations parametric in block are not difficult. They require no mastery of---choose the dubious metaphor you find more congenial---either brain surgery or rocket science. Dubious approximations, on the other hand, always gave/give trouble. On 2/17/12, Paul Gilmartin <paulgboul...@aim.com> wrote: > On Fri, 17 Feb 2012 10:39:03 -0600, Mark Zelden wrote: >> >>Although it is a crude and inaccurate conversion, one could use M instead >> of CYL basically >>1:1 and would be sure to get enough space since 1M is about 1.42 CYLs. >> If I did that at >>least I could picture it in my head the same way I have been doing with >> with CYL for >>my entire MF career. On a slightly larger scale, so what if I allocated >> in M and ended up with >>710 CYL instead of 500 CYL. (typical for me to use (500,500) for >> "large-ish" allocations). >> > It would seem to me that when the time came to convert from > 3330 to 3350 (e.g.), the simple path would have been to replace > "TRK" with "13030" (CYL slightly more complicated) and leave the > other numbers unchanged. JCL so modified would work on either > model during the transition, and be suitable for any future DASD. > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN > -- John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
