Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!usc!ginosko!uunet!portal!cup.portal.com!cliffhanger From: cliffhanger@cup.portal.com (Cliff C Heyer) Newsgroups: comp.arch Subject: 88000 vs 3081. Message-ID: <22130@cup.portal.com> Date: 14 Sep 89 02:09:50 GMT References: <21962@cup.portal.com> <1989Sep12.031453.22947@wolves.uucp> Organization: The Portal System (TM) Lines: 105 Re: Gregory/88000 vs 3081. >So what is a "workstation"? I have been unable to >make any real distinction between a "workstation" and a "high-performance PC". >The distinction (if there is one) is purely marketing hype. The distinction is purely I/O, *not* MIPS. All the 80386, 68030, etc. PCs are *not* running at full capacity due to memory & I/O subsystems being slower than the processor cycle time. Faster components blow the cost out of the water. Ask yourself why a 1974 DECsystem-10 could support 40 users with only 1 MIPS of processor power, and today we have PCs that have 8 MIPS but could NEVER handle 40 users with UNIX. The DECsystem-10 had a 20MB/s bus I/O BW, and had 2MB/s I/O to each of several MASSBUS disk drives. Today's PCs poke along with 5MB/s bus throughput and disk I/O of .2MB/sec (200KB/sec) even with "alleged" 1.5MB/sec SCSI. Try copying large files with your stopwatch for the proof. For example, on a (4 MIPS) VAXstation 3500 if I time the copy of a 1MB+ contiguous-sectored file from disk A to B, I get a rate of 1.3MB/second. (This is using SCSI w/large PC hard drives) That is: A=File size in millions of bytes. B=Stopwatch time to copy this file file from disk A to B. Throughput MB/sec = A/(B/2). (B is divided by 2 because B is the time to READ from A *and* write to B. Dividing by 2 gives the ballpark read or write time.) A VAXstation 3500 CPU w/box costs about $11K, and then you can hook up all the same SCSI stuff as the IBM PC. The cost is the same as a souped up 386, except the VAX CPU board goes for $10K instead of $3K. So you pay a *bit* more for that 1.3MB/sec. In fact, with the faster I/O you may get more work done with the 4 MIPS VAX than the Clipper, because the Clipper has memory wait states that slow it down to maybe 3 MIPS. Many 386 PCs give values of about only 200KB/sec which is not a "SCREAM" unless you compare to the PC XT or something (which is what manufacturers do to mislead you.) This is with SCSI too!!! One of the few exceptions is the Sun 386i which does a file read at 800KB/sec & write at 400KB/sec (however it was optimized for UNIX and does not run MSDOS too well). I have yet to see a PC that can SCREAM like a VAX. Just look at Byte. Almost EVERY benchmark they show for 1MB files is around 200KB/s for these machines. Try that on a VAX 11/780 and you'll get at least 800KB/s w/RP06s or 07s. Perhaps you could try this file copy on your machine and see what you get? I have heard of a few machines other than SUN that can do 750KB/sec. Use MSDOS to do this so there is no program overhead. If you only have one disk, you can copy to the NULL device(in which case don't divide B by 2). >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. Yup. And that's the way companies want it (& need to have it) If they all started to sell PCs today with 3MB/s to each disk and memory with those *non existent* PC profit margins, no one would buy their $1M mainframes in which case they would go broke. Also, to build 3MB/s to one disk on a PC would require expensive hardware which would raise the cost to $50,000+ per unit - making it no longer "cost effective" compared to the big iron. >It is cheaper (more effective) for us to have an Intergraph Clipper >chipset mounted in an AT-class PC take 8 hours to run our application than to >have an IBM-3081K do it in 3 and then send us back the results. If I remember, the 3081K (is it a 3081KX?) can give about 9 MIPS *per job*, first shipped in early '82, and had an internal BW of about 70MB/s. Your Clipper has more MIPS but no BW like 70MB/s. But the 70MB/s is divided up to about 3MB/s per disk channel and user. Even this is vastly faster than anything on the AT bus. >If I could have this processor (88000) in a machine with a decently >fast bus AND at a cost nearly the same, then it would be perfect. >...The VME bus based box would have >cost us THREE times the cost of the co-processor configuration! Fast components simply cost more, and it takes more time to engineer & test fast boards. Its the laws of physics. But what *you* can do is at least make sure you are getting state of the art for your buck. This means learning facts like the Amiga's ability to do 900KB/s DMA disk I/O, and not permitting a 33MHz 386 to be sold with 200KB/s without writing nasty letters to the editor of Infoworld, PC Week, etc. If you demand quality by making public the facts, the manufacturers will be forced to at least do the best they can. There are allot of ripoffs out there now because people have not educated themselves sufficiently to know what not to buy. I wish Infoworld and PC Magazine would include disk-to-disk copy benchmarks in all their tests. (but then I have not written to them either!) There is allegedly some kick-ass hardware out there in 386 AT land via SCSI/ESDI controllers ON BOARD bypassing the AT BUS. Mylex? ALR? I'm trying to find out before I buy. ONE thing is for sure - you can bet it won't come from IBM or DEC! They are too busy saving the BW for their *big iron*.