We are several guys to misunderstand something about compression. Here is the situation: Our interrogations come from MVS but I think it is true fo VM too.
We did 2 backups with DFDSS, 1 with the COMPRESS option and 1 without. For the 1st one, the restore too 3h20, the 2nd 6hrs ! 25 output tapes for both tests. This was made on 2084 with 10 procs,and really enough mips. Ok the software compression is very cpu consumming, hardware no. The question is what a software compression does, IDRC doesn't. Several of us think the algorithm used is very similar from one to the other, so !. Why that difference ! Others think, that IDRC is off, even if it is coded in the system (I verified this twice). Others says, we didn't pay to use IDRC. Others remember we had to install IDRC in the old past. So we don't have it. I'm looking for a firefly in this dark mess. Alain Benveniste
