Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU
Path: utzoo!decvax!ittatc!dcdwest!sdcsvax!ucbvax!daemon
From: daemon@ucbvax.BERKELEY.EDU (The devil himself)
Newsgroups: mod.computers.vax
Subject: (none)
Message-ID: <8606241621.AA27264@ohio-state.ARPA>
Date: Tue, 24-Jun-86 12:21:11 EDT
Article-I.D.: ohio-sta.8606241621.AA27264
Posted: Tue Jun 24 12:21:11 1986
Date-Received: Thu, 26-Jun-86 00:07:05 EDT
Organization: The ARPA Internet
Lines: 23
Keywords: VAX Unibus Controller Disk
Approved: info-vax@sri-kl.arpa


	Has anybody upgraded from a UDA50 to a UDA50-A?  These are both DEC
Unibus disk controllers, to run RA disks.  The latter is just like the former,
except with a larger buffer on board, thereby (presumably) improving effective
throughput of the controller. 

	What has been your experience?  If the disk controller was a bottleneck
before, how did you decide *it* was the problem?  How crowded is your Unibus?
Were there any installation or configuration difficulties?  Have you measured
any performance improvement?  How much improvement- enough to justify the
trade-up costs?  What kind of improvement - only with heavy, specifically disk
i/o bound jobs, or also with "general" paging loads?  Have there been effects
on the other devices on your Unibus?

	For sake of comparison, we are running VMS v4.3 (soon v4.4) on a 750 
with 8Mb memory and one Unibus.
						--Bob Sutterfield
						  OCES VAX System Manager
						  IRCC Facilities Management
						  The Ohio State University
						  bob%osuag.uucp@ohio-state.arpa

(* many of the above character strings are probably (r), (tm), or (c) DEC *)