pudding_man@lycos.com replied [in part]: > Restore from disk is relatively transparent to the user. > Restore from tape can be anything _but_ transparent to > an interactive user. It often freezes the user's > process while a tape mount request is issued. Even if > a tape drive is available, this can result in a > sizable wait. One might assume that HSM would be > configured to gobble up only large unaccessed files, > but I've seen it usurp little parm files, tiny > flat files, PDS's using maybe 2 tracks (about 115k), > etc. > > In fact, there are probably some folks out there that > feel that "DFHSM does more to bugger productivity than > any other software product in the mainframe environment". > I myself have had to write batch programs to restore > datasets so users could run interactive applications > unhindered.

Good point. When a hierarchical-storage program guarantees "30-minute response" as their maximum wait-time, you have to consider how many users would consider that to be 'transparent'. [Is that a :-) or a :-( statement?]

David -- David Cassell, CSC Cassell.David@epa.gov Senior computing specialist mathematical statistician