On Tuesday, 12/06/2005 at 12:56 EST, Jim Bohnsack <[EMAIL PROTECTED]> wrote: > I don't understand Alan's reply. Isn't the mdisk cache always a R/O > cache.
No. It is a write-through cache. That is, updates are made to both the cache and the device at write. The cache is maintained solely by CP without assistance from the hardware (disk controller). ...snip... > I know that there can be differences between what is actually > written on a mdisk directory and what the writer of the mdisk has in memory > until the disk is released, but that isn't a MDC consideration, I don't think. You're confusing the writing of the CMS disk directory at RELEASE with the I/O cache maintained by CP. Alan Altmark z/VM Development IBM Endicott
