On 08/09/2015 01:25 PM, Dave G4UGM wrote:
On the Honeywell we had a Tape Management System that managed the tapes. All the tapes were filed by tape number, and the system knew which file was on which tape. It would tell the operators which tape number to mount. It would also manage the scratch pool of expired tapes and tell them which tapes to have ready for new outputs. It also managed off site storage. We trusted it and never removed a write ring. If you mounted a tape with current data the system read the label and dis-mounted the tape....
I think that most large mainframe OSs eventually had a similar feature. When you had operators who were barely trained, it was best to leave it to the system.
On the CDC 60x and 65x, my tapes never had a write ring in them (what else are you going to play ring-toss with while waiting for your job to complete?). I always kept a few cards in my shirt pocked to stick behind the mounted reel and trip the write-enable mechanism (which latched). When the autoloading 66x drives came in, part of my world disappeared. I've never tried to see if that trick works on minicomputer reel-to-reel drives.
--Chuck
