Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site osu-eddie.UUCP Path: utzoo!watmath!clyde!cbosgd!osu-eddie!sutter From: sutter@osu-eddie.UUCP (Bob Sutterfield) Newsgroups: fa.info-vax Subject: Re: The value of a VAX 750 Message-ID: <620@osu-eddie.UUCP> Date: Mon, 23-Sep-85 09:42:42 EDT Article-I.D.: osu-eddi.620 Posted: Mon Sep 23 09:42:42 1985 Date-Received: Tue, 24-Sep-85 03:34:01 EDT References: <8509201641.AA17976@UCB-VAX.ARPA> Organization: OSU Instruction & Research Computer Center Lines: 40 > ... > 1) Is this true? (That is, is the 750 essentially an obsolete > paperweight nowadays?) > > 2) If true, can it be fixed? Are the defects in the 750 so basic that it > cannot be brought up to current standards of good performance by > replacing or upgrading certain parts? If it can be, is it known if DEC > has researched this and is planning to (or already does) provide a path > for making the 750 perform as well as the average new machine of > comparable size? > ... > Regards, > Will Martin > > ARPA/MILNET: wmartin@almsa-1.ARPA UUCP/Usenet: seismo!brl-bmd!wmartin There have always been rumors that the developers of the 750 were constrained by marketing considerations to slow down the CPU by inserting no-ops in the microcode. This was to keep it from being too close to the compute speed of the 780, which was a good first stab at implementing the architecture, but slower than an implementation using more current technology (witness the 785 upgrade). I once asked a DEC Field Service rep who claimed (and seemed) to know a good bit about the microcode situation, and he "unofficially" confirmed the story. If this is the case, a 750 could be pumped up to a "755" with nothing more than a new rev release of the console TU58, containing de-no-opped (is that a word?) microcode. This wouldn't, of course, make up for the paucity of buffered data paths and a slower UNIBUS (as compared to the 780), but it would certainly help. -- Human: Bob Sutterfield Facilities Management Division The Ohio State University Instruction & Research Computer Center Workplace: Ohio Cooperative Extension Service, Computer Management Group OCES VAX System Manager/Programmer (VMS) Mail: ...cbosgd!osu-eddie!sutter.UUCP or: sutter@ohio-state.CSNET or: 2120 Fyffe Rd rm 109, Columbus OH 43210 MaBell: (614) 422 - 9034