Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ames!ames.arc.nasa.gov!lamaster From: lamaster@ames.arc.nasa.gov (Hugh LaMaster) Newsgroups: comp.arch Subject: Re: *big iron* Message-ID: <32512@ames.arc.nasa.gov> Date: 25 Sep 89 17:25:22 GMT References: <21962@cup.portal.com> <1989Sep12.031453.22947@wolves.uucp> <22130@cup.portal.com> <1989Sep16.044013.429@wolves.uucp> <259@ssp1.idca.tds.philips.nl> <22308@cup.portal.com> <7981@cbmvax.UUCP> <11538@burdvax.PRC.Unisys.COM> <22488@cup.portal.com> Sender: usenet@ames.arc.nasa.gov Organization: NASA - Ames Research Center Lines: 37 In article <22488@cup.portal.com> cliffhanger@cup.portal.com (Cliff C Heyer) writes: >To clarify, *big iron* guys emphasize I/O on >their *mainframes*, but not on their *PCs*. Instead, they emphasize >This is the only answer I can come up with to explain why IBM >consistently puts out PCs that are substantially below average in "real" >disk I/O speed: 200KB/sec. Just look at Byte benchmarks. Plus I'm >So my belief is that some companies are trying to save I/O BW for their >*big iron* by purposefully handicapping the speed of their PCs. They Many of your points are well taken. In fact, many big companies don't make it a secret that they limit their user's options to force certain migration paths. The industry trade rags are full of speculation about such things, and sometimes even print a lot of criticism of the big boys for introducing new, high performance products too quickly - it is hard on the used equip. mkt. However, I think you are painting with too broad a brush to include Sun, MIPSCo, etc. in your list. Remember that the controllers you have been using for your comparisons to get ~1 MB/sec. through a filesystem are relatively new. Most of these controllers have been thoroughly *debugged* and in volume production (two prerequisites for full service companies to buy) for 6 mos. to one year. Sun now sells faster controllers that will do almost 1 MB/sec. on SMD disks through a Unix filesystem. I haven't had a chance to measure any IPI or synchronous SCSI disks. But it is unfair to use today's controllers to criticize systems shipped 1-2 years ago. The other thing that would probably help would be if more people said to salesrep from company X: "I am buying the system from company Y. Even though the CPU is only 10 MIPS instead of 20, it can stream data from 4 controllers simultaneously at 2.5MB/sec. each, with negligible CPU overhead." Hugh LaMaster, m/s 233-9, UUCP ames!lamaster NASA Ames Research Center ARPA lamaster@ames.arc.nasa.gov Moffett Field, CA 94035 Phone: (415)694-6117