On 19 May 2016 at 16:56, Martin Packer <[email protected]> wrote: > The whole disk is NOT in your virtual storage; The track window IS (IIRC).
Well I wasn't thinking *your* (the caller's) virtual storage; obviously it can't all be there. I was thinking there would be a VSM mapping of the whole device in *some* virtual space, but clearly this wouldn't have worked with 24-bit addressing. So I guess my mental model for this is wrong; presumably VIO is a driver of ASM at the same level as VSM is. And there must be a track (or some larger or smaller page-multiple) buffer that forms the interface to ASM. Well I guess going and looking at the code would be best; MVS 3.8 is still out there for the reading. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
