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
