On 30 Oct 2007 13:53:30 -0700, in bit.listserv.ibm-main you wrote: >> -----Original Message----- >> From: IBM Mainframe Discussion List >> [mailto:[EMAIL PROTECTED] On Behalf Of Howard Brazee >> Sent: Tuesday, October 30, 2007 3:41 PM >> To: [email protected] >> Subject: Re: z/OS 1.9 Features summary >> >> >> > >> ><SNIP> >> >But SDB came too late: if it had been present in rudimentary form, >> >supplying a valid but nonoptimal BLKSIZE, in OS/360 release 1, coding >> >BLKSIZE could always have been optional, and much of the rough >> >transition to present techniques could have been avoided. >> ><SNIP> >> >> It's amazing how hard it is to get shops to implement obvious >> improvements. While CoBOL has BLKSIZE=0, lots of people don't use >> AVGREC nor IF-THEN-ELSE-ENDIF even today. > >I agree. I have overheard programmers complaining that they could figure >out the number of cylinders needed for a give number of records. But >they won't look at using the newer (but now quite old) allocation by >number of records. That's because "I understand cylinders".
Unfortunately for VSAM, allocation in records can give you bad CA sizes because IBM in their infinite lack of wisdom (excessive sarcasm but it is one of my hot buttons) decided that we didn't need the equivalent of ROUND. Thus with the wrong allocation, a data set that would have a 5 cylinder primary might get an 8 track secondary so the CI size would be 8 tracks. Need I mention what that does to space allocation and index levels. > >> >> We used to calculate out necessary SORTWORK for count-key devices. Now >> we just throw more DASD at the job and don't waste our time trying to >> be close. But we haven't used the tools provided enough to make the >> old ways rare. >> > >We implemented the ICEMAC to simply override the JCL sortwork and >calculate the amount needed. The only time this fails is when we sort a >file with is compressed using BMC's Data Accelerator product. Then the >poor programmer just try to allocate 12 3390-3 volumes of sortwork and >pray. ---------------------------------------------------------------------- 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
