On Fri, 20 Nov 2015 06:58:42 -0500, John Eells wrote: >For the curious, IDCAMS does indeed use STOW (with I) to delete all the >members of a PDS or PDSE. This is not only fast, but it eliminates any >need to compress a PDS afterward. (Had you come to SHARE, you might have >known that--hint, hint. ;-) > I understand that the old CBT technique for PDS (doesn't work for PDSE) writes 8x'FF' at the beginning of the directory, then EOF at the beginning of the data area (and/or resets DS1LSTAR?) No compression should be necessary.
>Also, this function has been available since z/OS V1.12, so everybody >running on a supported release can use it. > So many inferior alternatives have been suggested in this thread that I submitted an RCF, even though it comes uncomfortably close to a discussion of internals: Hello, MHVRCFs, In: Required Parameters (for the DELETE command) z/OS DFSMS Access Method Services Commands SC23-6846-01 I read: If a member in the list matches the filter criteria, the member is deleted. If you specify the entryname in the format of a partition[ed] data set, pdsname(*) or pdsname(**) , the command deletes all the members in the partition data set. If the partitioned[ed] data set is not a PDSE, the directory is reinitailized when using pdsname(*) , but not for pdsname(**). (Spelling suggestions in "[...]") This ought to mention that IDCAMS DELETE pdsname(*) uses a highly efficient technique and programmers should prefer it over other techniques, even some which remain described in other (obsolescent) IBM publications. (How does one delete all members of a non-PDSE without reinitializing the directory? It seems that 8x'FF' must be written at the beginning, and then the directory is de facto initialized. Does "reinitialized" mean that all further directory blocks are overwritten (with binary zeroes?) to remove any residual data?) Thanks, gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
