Two great answers right away, thanks! I *love* the "get the compression ratio" solution, it sounds perfect so far.
I have an obvious question on the 3490E though. You say there is a set of tracks "going AND coming". Since actual tape length isn't a specification, just a minimum is, how would a hardware duplication device handle a 3490E? In theory it wouldn't be able to, would it? David Logan -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Vernooy, C.P. - SPLXM Sent: Friday, January 18, 2008 7:18 AM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: How to find "current tape length" programatically "David Logan" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>... > If I was to a tape, is there a way to programmatically know when I am > nearing, or have hit, the end of the "guaranteed" tape length? I forget if > it's 3480 or 3490E tape that guarantees 1100 feet, but if I were writing to > a tape, is there a way to find out that I was still under this value? > > > > Our tape duplication service does a tape-to-tape hardware copy, so we cannot > have multi-file tapes, so we cannot simply write to EOT and switch to the > next tape. We need a way to write EOT within the minimum tape length > specification. > > > > In particular, I am questioning whether or not I will ever be able to find > out if I am still within my minimum specification when I am using IDRC > compression. Admittedly, I know very little about what the actual tape looks > like when I use compression. Maybe there is a better way to stay within the > minimum tape length than to find out how much tape I have written. > > > > Any ideas? On either knowing tape length, or my root problem, knowing when > to stop writing compressed data to stay within the specification? > > > > Thanks! > > > > David Logan I know how our Dasd Management product does it: It gets the tape code from the control unit and decides from its own internal table the real tapelength. I suppose you have this value for a given tape. Then it writes to the tape, asks the IDRC compression ratio from the control unit and calculated the number of feet consumed by the written blocks and their interblock gaps. It then knows how much tape is left and if more data will fit. Hope this helps. Kees. ********************************************************************** For information, services and offers, please visit our web site: http://www.klm.com. This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message. Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt. Koninklijke Luchtvaart Maatschappij N.V. (also known as KLM Royal Dutch Airlines) is registered in Amstelveen, The Netherlands, with registered number 33014286 ********************************************************************** ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
