Peter Hunkeler wrote: >Based on a discussion here, I got curious on how OPEN in append mode >(DISP=MOD) finds the end of the current data in a DASD PS data set.
>3. Once the last volume is identified, OPEN needs to find the end of current >valid data on that volume. This is similar what I see when processing tapes. Only the LAST tape is mounted for DISP=MOD. Even the VTS is faithfully reproducing this behaviour. >If the above is roughly correct, then processing for OPEN in append mode will >increase with the number of extents and volumes. On the other hand, processing >for OPEN in replace mode (DISP=OLD) will not change, no matter on how many >extents/volumes the data set has allocated from previous processing. Uhm, do you want to OPEN it by standard methods (Catalog+SMS and let system do the dirty work locating EOF) or do you just want to bypass normal processing and work only via the volser and the vtoc? If you want to bypass normal processing, how will you then handle addition of a new extent taking in account of volume limits? Groete / Greetings Elardus Engelbrecht ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
