Perhaps by measuring the amount of tape left on the spindle? A light, possibly laser, shining on a tangent to the spindle at a specified height could be detected only when the tape remaining is not thick enough to block the light. This would remove any dependence on stickers which are supposed to be x feet or x inches from the physical end of the tape. There are other possibilities. For example, compare the speed in RPM of the two spindles. When the take-up spindle is over half full, it moves at a slower RPM than the other in order to keep the same linear rate for the tape. This could be used to determine the EOT.
I would hope that the use of stickers to denote EOT would have gone out way back in my career. We used stickers in pre-S/360 days and they were fraught with problems then. Have you ever had to clean the heads and capstans of a tape drive that had become fouled with a sticker that did not stay stuck? Regards, Richard Schuh > -----Original Message----- > From: The IBM z/VM Operating System > [mailto:[EMAIL PROTECTED] On Behalf Of Stracka, James (GTS) > Sent: Friday, June 06, 2008 8:36 AM > To: IBMVM@LISTSERV.UARK.EDU > Subject: Re: Backup: Twinning Tapes to Remote Tape Unit > > Now that is interesting. How does that OS/390 utility know > where the EOT reflector is located unless it spins the entire > tape first? > > -----Original Message----- > From: The IBM z/VM Operating System > [mailto:[EMAIL PROTECTED] On Behalf Of McKown, John > Sent: Friday, June 06, 2008 9:48 AM > To: IBMVM@LISTSERV.UARK.EDU > Subject: Re: Backup: Twinning Tapes to Remote Tape Unit > > > Curiousity question, because I don't know VM:Backup, is there > a way to tell VM:Backup to only use n% of a tape? Our z/OS > backup utility can be told to do this. If this is possible, > then you could fill a tape up to, say, 80% and be fairly > confident that the second tape would be long enough to hold that data. > -------------------------------------------------------- > > This message w/attachments (message) may be privileged, > confidential or proprietary, and if you are not an intended > recipient, please notify the sender, do not use or share it > and delete it. Unless specifically indicated, this message is > not an offer to sell or a solicitation of any investment > products or other financial product or service, an official > confirmation of any transaction, or an official statement of > Merrill Lynch. Subject to applicable law, Merrill Lynch may > monitor, review and retain e-communications (EC) traveling > through its networks/systems. The laws of the country of each > sender/recipient may impact the handling of EC, and EC may be > archived, supervised and produced in countries other than the > country in which you are located. This message cannot be > guaranteed to be secure or error-free. This message is > subject to terms available at the following link: > http://www.ml.com/e-communications_terms/. By messaging with > Merrill Lynch you consent to the foregoing. > -------------------------------------------------------- >
