Article View: comp.arch
Article #20491Re: Drum memory
From: Tom Littauer
Date: Fri, 24 Mar 1989 14:29
Date: Fri, 24 Mar 1989 14:29
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1545 bytes
In article <95741@sun.Eng.Sun.COM> jamesa@arabian.Sun.COM (James D. Allen) writes:
A good summary of the use of drums on 370-architecture machines.
A minor nit: these "drums" were implemented as head-per-track disks for
ease of manufacture (cost) and capacity.
> Data-intensive applications often read their data in large chunks.
> A 64k chunk takes 22 milliseconds to read even at 3 MBS datarate.
> For this reason, datarate becomes as important as seek latency
> for these high-powered users and this tends to reduce the advantage
> of fixed-head disks.
Correct. The need to improve on this is one of the things that drove us
to introduce 4.5MB channels and a 4.5MB data rate on our solid-state "disk".
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!apple!amdahl!littauer From: littauer@uts.amdahl.com (Tom Littauer) Newsgroups: comp.arch Subject: Re: Drum memory Message-ID: <0fsqPccLkF1010aRTpU@amdahl.uts.amdahl.com> Date: 24 Mar 89 14:29:52 GMT References: <21976@lll-winken.LLNL.GOV> <28411@ucbvax.BERKELEY.EDU> <1487@wpi.wpi.edu> <95741@sun.Eng.Sun.COM> Reply-To: littauer@amdahl.uts.amdahl.com (Tom Littauer) Organization: Amdahl Corporation, Sunnyvale CA Lines: 23