>>I will only get the primary space of 5000 cylinders, and the other 14x2000 >>cylinders is never used. Is that right?
Billy, No. Incorrect. DFSORT will make use of BOTH primary and secondary space allocations ( 1 primary + 15 Secondary) for a total of 16 extents. So if you allocated 1 sortwk dataset with (CYL,(5000,2000)), then DFSORT would use 5000 + 15* 2000 = 5000 + 30000 = 35,000 cylinders. Also note that the secondary extents will only come into picture ONLY when needed. >>Is there a written explanation I can forward to the programmers so they >>understand this? >>Also (since I know it will come), is there any good way to calculate how much >>DASD sortwork would be used? I know this depends on what is in memory at the >>time, but want to get a better handle on how Sort determines what it needs. I would suggest that you use DFSORT's Dynamic Allocation as it will allocate the required workspace optimally rather than programmers calculating it. The reason is you don't want to change the allocation every time there is an increase/decrease in the number of records to be sorted. Having said that, here is a general formula that you want to use. The amount of sortwk space required depends on the size of the file. It usually ranges from 1.3X to 1.8X of the size of the file to be sorted depending on the sorting path that DFSORT chose. Filesize = Number of records * Avg length of the record ( for Fixed length RECFM=F or FB , it is the LRECL value, or RECFM=V or RECFM=VB is the average length of the record) However, that range is applicable ONLY when the entire file is being sorted using Disk workspace. DFSORT has the capability of using memory (real and auxiliary storage) and if it runs out of it, it will then use disk workspace. Thanks, Kolusu ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
