Thank you, found it here - https://www.ibm.com/docs/en/zos/2.4.0?topic=keywords-compress
Is it just me or does one need to be in 100% concentration just to understand what this means. A simple decision flowchart would have made it a lot easier on the common man's brain. - KB ------- Original Message ------- On Sunday, April 16th, 2023 at 8:20 AM, Michael Oujesky <[email protected]> wrote: > SMS compression is limited to sequential DASD datasets, but some > utilities (ADRDSSU) uses it internally for tape files. For those > that do, turning off IRDC save cycles in the tape controller. > > > > At 09:12 PM 4/15/2023, kekronbekron wrote: > > > And an add-on question if I may - zEDC or z15+ on-chip > > compression... does this apply only to data heading to disk, or does > > it apply for data heading to tape too. > > If it applies for data heading to tape also, does that mean there > > are 2 levels of compression now - CP's on-chip compression + zstd on > > the TS7700? > > > > - KB > > > > ------- Original Message ------- > > On Sunday, April 16th, 2023 at 7:17 AM, John Young > > [email protected] wrote: > > > > > Although my post today is probably rhetorical question, I wanted > > > to find out whether this matters anymore or not. > > > > > > Back in the late 2000's, IBM developed encryption facilities > > > within the tape drives, as this is also where compression was being > > > performed. The idea was that compression of data must occur before > > > encryption, as encrypted data does not compress well, and obviates > > > the use of compression. > > > > > > Nowadays, we've got pervasive encryption on z/OS. As a result, > > > any data that is backed up (for instance, ADRDSSU/FDR), is already > > > encrypted. > > > > > > Also, we now have zEDC, to compress data prior to storage, > > > typically on disk. > > > > > > To my question: With all the encryption and compression being > > > performed on disk, to what degree does TAPE COMPRESSION matter anymore? > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to [email protected] with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
