Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!elsie!imsvax!ted From: ted@imsvax.UUCP (Ted Holden) Newsgroups: comp.sys.ibm.pc Subject: Re: Mainframe vs Micro Message-ID: <658@imsvax.UUCP> Date: Sun, 4-Jan-87 16:41:54 EST Article-I.D.: imsvax.658 Posted: Sun Jan 4 16:41:54 1987 Date-Received: Sun, 4-Jan-87 21:57:43 EST Organization: IMS Inc, Rockville MD Lines: 87 Tim Kay (Caltech) writes: >In article <657@imsvax.UUCP> ted@imsvax.UUCP (Ted Holden) writes: >>There are several points to consider concerning the mainframe/micro question >>as it relates to databases. The 32 meg limit doesn't apply to Novell Netware. >You are totally in the wrong ball park. PCs aren't going to encroach on >mainfames just because the 32M limit was broken. A _typical_ drive that >IBM sells (3380) has about 600 Mbytes on it. A _typical_ machine they sell >will have anywhere from 10 to 500 of these drives on it. A PC can handle >only two drives. One of the main concerns in designing the XA architecture >at IBM was that installations were running out of address space for numbering >devices (disks, tape drives, terminals, CTCAs, etc.). The old 370 >architecture can handle 4,096 devices! The new XA architecture can handle >significantly more. I'm not the one who's in the wrong ballpark. The comparison between individual PCs and individual mainframes is no more meaningful than that between an individual army ant and one of the creatures which ARMIES of such small army ants EAT. What is important is the servers reach a certain level of power and sophistication, which they have, and the state of the control soft- ware for the army (e.g. Novell's Netware). These are good enough for such PC armies to eat VAX class machines today and I can't believe they won't be eating IBM mainframes in another year or two. >Typically, a single machine configured as above is not adequate, so IBM >offers (and has offered for about a thousand years now) the ability to >network these large machines. There are installations that have dozens >of the machines (of the size I just mentioned) networked together. And cost many times what equivalent compute power in the form of PCs would. As long as such systems could do things which small computers physically couldn't do, such costs could have been justified. The day when all such bets are off is rapidly approaching. >The present discussion started when a claim was put forward that PCs are cutting >into IBM's mainframe market. DEC offers no machine that is anywhere near the >power of IBM's mainframes. IBM can _routinely_ put hundreds of terminals >on a single machine, and it will perform well. ...... Assuming all but a few of these terminals are turned off. At every mainframe installation I've ever worked at or with, there was money to be made by some one selling IBM or Univac PUNCHING BAGS, just ordinary 70 lb heavy bags with "IBM" or "UNIVAC" or maybe "CDC" written on them. The people would have lined up. I mean, if any of these statements about mainframes serving 200 or 700 users at minimal (one guy quoted .05 for a CDC) load were true, PCs would never have seen the light of day. Get serious. >I will rephrase a statement that I made earlier. Most people have absolutely >no idea what the bulk of the computing power in this country is used for. I've been involved with porting mainframe applications to small computers for some time now, mostly because people finally couldn't stand dealing with the mainframes. Aside from the obvious database kinds of things, these have included large Fortran programs, including the Census X-11 time series routine and a couple of risk-analysis types of programs from Social Security in Baltimore, all of which ran way the hell faster on generic 68000 machines than they ever did on these organizations' Univac mainframes. Such applications are probably pretty typical of how the "bulk of the computing power in this country" is used. >None of this discussion starts to consider machines like Crays or IBM >3090s with vector processors. They can compute thousands of times >faster than a PC. An 8087, for example is about 5 kiloflops. A >68881 is about 30 kiloflops. A Cray XMP 48 (by now an old machine) >was about 1 gigaflop. This is a factor of 1,000,000,000 / 30,000 , >= 33,000 difference in performance. No argument here. The Crays will always be with us. Good coding on a 68020 device with Witech boards can approach a reasonable fraction of Cray power FOR SPECIFIC APPLICATIONS, as witnessed by the Silicon Graphics devices for example, but not for general usage. The Intel world doesn't come close here. Note, however, that supercomputing is a really small fraction of computer usage in the world, and that PC clone vendors will probably be satisfied with the other 95 percent. Ted Holden IMS