um, at the risk of the wrath of Chuckie, not quite. The directory is treated as CP virtual storage. So some of it is usually resident (at least the index pages) and the rest is treated as nice preferred page i/o to the drct area. With storage sizes what they are these days, I'm thinking a lot of the directory is resident. David
________________________________ From: The IBM z/VM Operating System on behalf of Alan Altmark Sent: Thu 3/15/2007 4:52 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: [IBMVM] Historical curiousity question. On Thursday, 03/15/2007 at 10:55 EST, "McKown, John" <[EMAIL PROTECTED]> wrote: > > The CP Directory has information for each user. At logon time, > > the information about a single user is available very quickly. > > This makes sense to me. IIRC, the VM directory is memory resident so all > this information is "instantly" available, making for a very fast logon. Actually, it isn't. When a user logs on and a VMDBK is created for them, SOME of the information in the directory is cached in memory. Other things, such as LINK, require a trip to DASD. Since reading the user's directory entry is a relatively rare event, that's ok. Alan Altmark z/VM Development IBM Endicott
