And plus. Please do not forget about contents of backuped data, it may be not compressable at all ;) So, this DASD requires maximum tape count. And a big number of clear DASDs (just formatted) may fit into one tape at the same time.
The software compression case permits to calculate estimated tape count, and the hardware -- not. Anyway, you should run the backup process twice (with all limitations like data isolation, write protection, etc.) Do you need that? Always keep in mind the maximum count of tapes for the first run. -- WBR, =Maxim Bochagov IBM Russia, PTK development team
