As far as I know all ISPF compress operations are done using IEBCOPY, If so, IEBCOPY enques on IEWxxx and staw to protect the directory from being manipulated. It does not protect the directory from read, so if CICS or any other program that has in storage copy of the PDS directory, can be effected from the fact that directory and actual space allocation are not consistent. I believe that the source for information is ISPF customization guide where you might be abale to specify the compression module name and the utilities reference for IEBCOPY (if this is what you use to compress). This was extructed from the planning & customization guide (See the sentence starting with "Instead of using IEBCOPY": *
Compress request exit * In the ISPF configuration table keyword file, this exit is set with the keywords COMPRESS_UTILITY_PROGRAM_EXIT (if your exit is a program) and COMPRESS_UTILITY_CLIST_EXIT (if your exit is a CLIST). Instead of using the IEBCOPY system utility interface that PDF provides, you can specify that PDF use an installation-written exit routine to handle requests to compress partitioned data sets under options 3.1, 3.4, and the LMCOMP service. When the compress exit gets control, the data set will have already been allocated and enqueued as exclusive. The exit will have to re-allocate the data set to a specific ddname. As part of termination processing, the exit must free the allocated ddname. The FREE operation must not be done by data set name. PDF allows the exit routine to: v Use an alternate compression technique v Provide backup before allowing normal PDF compression v Selectively prevent compression. PDF program or CLIST. All ISPF and system services are available. ITschak On Mon, Oct 12, 2009 at 10:27 AM, Gilbert Saint-Flour <usenet5...@yahoo.com>wrote: > Hello: > > I posted a message a week ago on ISPF-L and received no answer; > hopefully, I'll get a good one here. Here it is: > > If I enter HELP on the DDLIST panel, I see this: > C Compress a PDS using the existing allocation. > When I use DDLIST to display allocated data sets, I see most of them with > DISP=(SHR,KEEP). When I use the C (or Z) line action to compress a PDS > allocated with DISP=SHR, DDLIST allocates it again with DISP=SHR and > compresses it using IEBCOPY. > > I am concerned with the compression of a load-library with DISP=SHR which > can > cause problems, particularily if it's allocated in CICS or LLA. DDLIST > seems > different from ISPF options 3.1, 3.4 and 11, which, if I'm not mistaken, > allocate a PDS with DISP=OLD to compress it. > > Where can I find a detailed description of what DDLIST does to compress a > PDS ? Does it issue ISPF-style ENQs? How about link-edit or IMS ENQs? > If it's an LLA library, does it tell LLA to refresh it ? Shouldn't DDLIST > warn us from problems that could happen because of DISP=SHR? > > Thank you for your help. > > -- > Gilbert Saint-Flour > GSF Software > http://gsf-soft.com > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
