On Wednesday 03 April 2002 08:58 am, Uncle George wrote: >Guess I'm from old school. Older 9trk drives when left on, > continually have the vacuum on, and under constant tension. Its > not healthy for the tape. Does that happen with a DLT tape, how > about the DDS tapes.
I'd have to assume that the DLT, which I know nothing about, shares such a feature with which nearly all other drives, including professional vcr's, that has a timeout of a minute or so, and, like the DDS drives I have, does a backout of the loading mechanism thereby removing the tape from contact with the scanner drum, usually with one supply or takeup spindle braked, and shuts the head drum down at the same time. The drive then gradually cools to match its resting temps and the tape is mostly protected and not subjected to the internal heat rise the drive does when its active. I do not consider the roughly 80 degree temps my tapes have when I eject the magazine as being that hard on the tape if the tape is not in motion. I'd love to see the tapes stored and used at or slightly below 50 degrees F, and <50% relative humidity as the tape is many times less abrasive then. Some TV stations have even gone so far as to store their tapes in a small room adjacent to the control room which is maintained in the 40 degree and <40% range. Everyting lasts longer, a lot longer. The tape makers themselves recommend it too, and have data to show that a tape used and stored at 90/90 for temp and RH, is not just marginally more abrasive, but dozens of times more abrasive. That effect was brought home to me many years ago when a headwheel failed in a now old 2" broadcast vtr. The wheel had over 7000 hours of runtime on it, and the failure was in a rotary transformer. We sent it back for repair. It was re-installed and ran till something over 9000 runtime hours was used and it was worn out. That headwheel came with a 200 hour prorated warranty as it had soft tips. No, I didn't forget a decimal there. The machine was in a precipitron clean, dry, cold room. Under more usual conditions I've seen them fail in 125 hours. But we don't have those conditions inside the typical computers case, not by a long shot. >I would NOT like a "live" tape to be left > in the drive for long periods of time. Who knows when a power > failure will hit, who knows when the drive will go awol. An > unloaded tape, immediately after backup, is safe from other > folks, as well as the server, writing onto it. I'd consider that a problem only in those drives like older QIC's, that leave everything engaged for long periods of time, thereby denting the drive rollers etc. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 98.7+% setiathome rank, not too shabby for a hillbilly
