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From: ram@shukra.UUCP
Newsgroups: comp.arch
Subject: Re: Disk Striping (description and references) plus class brief
Message-ID: <24787@sun.uucp>
Date: Mon, 3-Aug-87 20:08:34 EDT
Article-I.D.: sun.24787
Posted: Mon Aug  3 20:08:34 1987
Date-Received: Wed, 5-Aug-87 03:45:27 EDT
References: <2432@ames.arpa>
Sender: news@sun.uucp
Lines: 39
Summary: classes and groups

In article <2432@ames.arpa>, eugene@pioneer.arpa (Eugene Miya N.) writes:
> >OK.  I'll bite.  And what classes are defined and what do they mean?
> 
> The rating was developed to Sid Fernbach and George Michael which the
> two were are Lawrence Livermore Lab (before they became LLNL).  I have
> seen charts on the wall at LLNL which detail some of this.
> Supercomputers come in 6 "classes."  Each class should be a factor of 4

    Seems like this grouping/classifying is rather rigid.  The performance
    groups are like sliding windows, which keep changing regularly.  Instead
    of inventing new classes (for better performance mechines)
    why not define as follows.  Determine the fastest machine (don't ask me
    how and assume we don't quarrel over numbers) - from that,
    all machines that reach within 80% of its performance say, will be
    the supercomputer class (otherwise we will run out of superlatives very
    soon).  The mini-super or super-mini (I don't understand which goes
    ahead of which) could take the next 20% of the performance slot and
    ulimately the eternal PC taking last 1-2%.  So, in year 2000, hopefully
    CRAY-1 should be in the PC slot and CRAY-2S in the workstation slot.(Room
    heater will become obsolete :-)) I guess this scheme has to be
    militaristically enforced on the marketing guys :-).
    
> 
> I meant to say DISK STRIPING.  This is the distribution of data across
> multiple "spindles" in order to 1) increase total bandwidth, 2) for
> reasons of fault-tolerance (like Tandems), 3) other miscellaneous
> reasons.
  
    So, my guess was right.  Does the CM use such a feature to obtain
    a large BW?  How come IBM's disk farms don't have these, or do they?
> 
> --eugene miya
>   NASA Ames Research Center

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   Renu Raman				ARPA:ram@sun.com
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