Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ico!ism780c!haddock!suitti From: suitti@haddock.ima.isc.com (Stephen Uitti) Newsgroups: comp.arch Subject: Re: PC vs. mainframe I/O (Re: SCSI on steroids) Message-ID: <14596@haddock.ima.isc.com> Date: 13 Sep 89 16:32:55 GMT References: <21962@cup.portal.com> <1989Sep12.031453.22947@wolves.uucp> Reply-To: suitti@haddock.ima.isc.com (Stephen Uitti) Organization: Interactive Systems, Cambridge, MA 02138-5302 Lines: 64 In article <1989Sep12.031453.22947@wolves.uucp> ggw@wolves.UUCP (Gregory G. Woodbury) writes: >In article <21962@cup.portal.com> cliffhanger@cup.portal.com (Cliff C Heyer) writes: >>Now, on the subject of PCs and disk I/O... >>What *will* change this though is the emergence of >>new low cost chips such as the NCR53C700 SCSI chip...[RAM, etc] > We are/have been replacing our dependency on mainframe computing >by acquiring a network of dedicated, "high performance" (and relatively) >low cost "PC's". Some of these things are "workstations", but they all >use the AT style PC buss, and take too bloody long to do the disk i/o. > >It is cheaper (more effective) for us to have... > ...an 88000 based co-processor in a '386 >33 MHz PC with 1.2 GBytes of disk and 24 MB of memory can cost ~$30,000. >This is amortizable over several years. Three years, max. >The full cost recovery for this >pc/workstation (assuming 40 hr weeks!) is < $6.00/hour! The University >owned (consortium) mainframe limits normal jobs to 5.5MB of memory and costs >$150.00/hour! Our application benchmark took ~1 hour to run on the 3081. >It takes about 1.8 hours to run on the 88000, and costs a hell of a lot less >'cause there isn't a memory premium overhead on the cost! I've worked at "University comp centers". The big cost is not the hardware. It is the people. This is true even when the machines are huge/expensive. These centers typically serve many people with small needs. They purchase machines that are extremely cost effective for the work that gets done on them. They typically don't optimize machines for individual users. They tend to discourage serious use by charging for hardware time, rather than charging for the (expensive) administrative overhead. The sites i worked at used VAXen, IBMs, etc. One site had about 100 pc's (some were macs). It is cheaper (capital outlay) to be your own sysop on your own PC. Most people only do word processing and a few compiles. No big deal. My 4.77 MHz 8088 based PC/XT can do this. $1000 and you are set for life. Still, we had users who didn't know how to boot a PC. If your comp center bought your system for your exclusive use, it would obviously cost more than $6/hr. My salary was more than that. Ok, so i ran several machines... a big comp center has lots more overhead. The comp center will attempt to account for time on the machine. Sigh. If you're lucky, there will be resources left to grant to users. I did see one prof get a machine, real cheap. He then expected it to run itself. The OS didn't magically get easier to run just because the machines was cheap. When his disk crashed, and no backups were done, there wasn't a whole lot that anyone could do, at any price. Oh, yes, maintenance. Do you think your PC won't break, being used 40 hrs/week? Get a good contract. If you don't need a sysop, then don't hire one. If you are the default sysop, make sure it doesn't take all your time - pay some attention to the application. For new and clueless users who don't have a lot of money, buy a Mac. Sign up for a maintenance contract. Maybe take some classes in word processing. Or read the manuals... Stephen.