Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!princeton!caip!lll-crg!seismo!rochester!ritcv!cci632!ccird1!rb From: rb@ccird1.UUCP (Rex Ballard) Newsgroups: net.arch,net.micro.att Subject: Re: AT&T MIPS claim Message-ID: <448@ccird1.UUCP> Date: Fri, 6-Jun-86 10:45:43 EDT Article-I.D.: ccird1.448 Posted: Fri Jun 6 10:45:43 1986 Date-Received: Sun, 8-Jun-86 04:15:17 EDT References: <577@scirtp.UUCP> <266@comm.UUCP> Reply-To: rb@ccird1.UUCP (Rex Ballard) Distribution: net Organization: CCI Rochester Development, Rochester NY Lines: 46 Xref: watmath net.arch:3389 net.micro.att:1270 Summary: Users/system, when it counts, when it doesn't. In article <266@comm.UUCP> dave@comm.UUCP (Dave Brownell) writes: >In article <577@scirtp.UUCP> dfh@scirtp.UUCP (David F. Hinnant) writes: >> ... They made this interesting claim that the UNIX PC gives >> you "75% of the power of a VAX 11/780" for "only 7% of the cost". >> Arrgh. ... Is this the MIP rating for the >> 68010 as compared to the VAX? Looks like it. One really couldn't ask >> for a better example of the Meaningless Index of Performance. I've seen >> many a 780 run with more than 20 users. I'd like to see you put that >> many on a UNIX PC that I found can barely support one. > >This is Apples and Oranges ... a MIP, however meaningless, is a CPU benchmark, >and a "user" is a rather ill-defined I/O benchmark ... and I do believe >the I/O on the 7300 is not up to the CPU. Maybe when someone comes up >with a realistic I/O benchmark we can really start comparing UNIX hardware. >(Yes, that marketing claim is absurd.) You can say that again, I've been enhancing an 8085 box that supports 16 users :-). What types of support, I/O, and terminals is each supporting? Is the UNIX PC running bit-mapped video? Is the VAX driving relatively smart terminals (VT-100,VT-52,Tektronix,...)? Are the VAX terminals connected at 9600 baud? What types of "Demand Paging" are on the PC?. How do the disk drives compare? There are specific applications where "user response time" is an important factor, and MIPs take a "back seat". We sell a system that supports 1000 searches/second on 1 million listings, but you wouldn't believe the hardware/software that does this. We also sell a 68012 configuration rated nominally at 2x780, and some brief exposures to it leave me a believer, but in the "32 user mode", there is a lot of smarts required by the "Terminals". A VAX with 20 VT-100's on it, is really running about 6 MIPS, if you include the CPU power of each of the VT-100's. A 5/32 with 32 "PowerTerminals" is running about 18 MIPS. You just don't look at the MIPS of the terminals, because you don't "Program" them. In fact, they run at least an ANSI 3.64 interpreter! The "PT's" actually run much of the editing functions right on the terminal. Conversely, a VAX running bit-mapped graphics and video to each user would likely "come to it's knees" with fewer than 4 users, if EVERYTHING had to be "painted" on the screen. MIPs are great. You can distribute them any way you want?