From mboxrd@z Thu Jan 1 00:00:00 1970 From: bqt@update.uu.se (Johnny Billquist) Date: Thu, 20 Mar 2003 00:34:21 +0100 (CET) Subject: [pups] Progress on 2.11BSD kernel In-Reply-To: <200303192308.h2JN8kD04865@moe.2bsd.com> Message-ID: On Wed, 19 Mar 2003, Steven M. Schultz wrote: > The buffer cache must be entirely mapped by UMRs - so if you have a > 32KB buffer the kernel will reserve 4 UMRs on a UNIBUS system. > Realistically a 64KB buffer cache is about the maximum a UNIBUS system > can have because that takes 8 of the UMRs. Are the UMRs allocated and set up statically? (I haven't looked inside 2BSD for a while now, and can't remember much of the internals anymore.) > With the old (thankfully no longer in use, etc) 3Com ethernet boards > you had to disable 4 UMRs so the system could access the memory in the > card - that made for a very tight fit. How many UMRs does the system use? 8 for buffer cache, you might expect one or two DH11s, that would require a few more, ethernet takes another few, but it seems there shouldn't be such a shortage. What did I miss? Johnny Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at update.uu.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol