No, for non-CMS guests such as z/OS, z/VSE, TPF and Linux, their tape I/O is via the SSCH instruction. That can ONLY be intercepted by the z/VM Control Program (CP). That would require a heavy modification to the operating system and since IBM already has a hardware solution to virtual tape requirements, I doubt that they will pursue such a modification.
If you need Virtual Tape capability for all tape I/O from any kind of VM guest, then look for a hardware solution. /Tom Kern /U.S. Dept of Energy /301-903-2211 On Thu, 26 Jun 2008 22:37:42 +0200, Lindy Mayfield <[EMAIL PROTECTED]> wrote: >Thank you, Tom. That is very informative. > >Does this apply (somehow indirectly) to, for example, inside a z/OS guest which attaches and accesses a tape drive? > >-----Original Message----- >From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Thomas Kern >Sent: 26. kesäkuuta 2008 19:49 >To: [email protected] >Subject: Re: Virtual tape on VM > >For programs inside a virtual machine that use standard CMS TAPEIO macros >for their I/O, you can create a nucleus extension that intercepts the tape >I/O and transforms it in some way. Two examples are the BLOCKIO program that >was used by lots of installations to increase the real blocksize of data on >tape from the 4K level of VMFPLC2 (before it was enhanced for larger >blksizes), and a tape encryption product that called VM/Encrypt-Tape from >VSoft Software (http://www.vsoft-software.com/products.html). > >In your new nucleus extenstion, you could direct that tape I/O to a CMS file >on one of that user's minidisks or via IUCV to some central server for >storage on it minidisks. The actual data packets could be compressed by the >nucleus extenstion or in the central server if that is how you want to >create your Virtual Tape System. > >Intercepting CP's I/O (like SPXTAPE) or SSCH I/O (like DDR) would not be >feasible. but there are ways of not using those programs. > >/Tom Kern >/U.S. Dept of Energy >/301-903-2211 ---------------------------------------------------------------------- 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
