Xref: utzoo comp.arch:11610 comp.databases:3772
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!tut.cis.ohio-state.edu!ucbvax!mtxinu!rtech!daveb
From: daveb@rtech.rtech.com (Dave Brower)
Newsgroups: comp.arch,comp.databases
Subject: Re: *big iron*
Message-ID: <3752@rtech.rtech.com>
Date: 3 Oct 89 05:06:18 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> <24950@lou
Reply-To: daveb@rtech.UUCP (Dave Brower)
Organization: Relational Technology Inc, Alameda CA
Lines: 21

some people wrote:
>>Cray DD-40 disk drives can support >10MB/sec through the operating
>>system (at least COS; I assume the case is also true for UNICOS).
>
>This brings up a point:  in what processing regimes does total
>sustained disk tranfer rate be the performance-limiting factor?
>

In many tp/database/business applications, CPU is fast enough that disk
bandwidth will soon be the limiting factor for many applications.  Some
airline reservation systems are said to have huge farms of disk where
only one or two tracks are used on the whole pack to avoid seeks, for
instance.  A 1000 tp/s database benchmark might easily require 10MB/sec
i/o throughput.  

Maybe Cray should change markets...

-dB
-- 
"Did you know that 'gullible' isn't in the dictionary?"
{amdahl, cbosgd, mtxinu, ptsfa, sun}!rtech!daveb daveb@rtech.uucp