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From: jc@odin.ucsd.edu (John Cornelius)
Newsgroups: comp.periphs
Subject: Re: Hard drive speeds
Message-ID: <6987@sdcsvax.UCSD.Edu>
Date: 27 Aug 89 17:57:02 GMT
References: <17640@ut-emx.UUCP> <16567@pasteur.Berkeley.EDU>
Reply-To: jc%andataco.uucp@ucsd.edu (John Cornelius)
Organization: Andataco
Lines: 24

In article <16567@pasteur.Berkeley.EDU> pmchen@mustard.Berkeley.EDU (Peter M. Chen) writes:
>In article <17640@ut-emx.UUCP> croley@walt.cc.utexas.edu (David T. Croley) writes:
>>
>>I am currently trying to come up with a rule of thumb so that I can
>>determine the relative speed of a hard drive.  I have seen drives
>>with fast access times and slow through-puts and drives with slow
>>access times and high through-puts.  Which is more important?
>
>Depends on your workload.  For workloads with large transfer sizes (or
>predominantly sequential accesses), throughput is more important (assuming your
>	.
>My guess is that, for Unix, access time is more important, since transfer
>sizes are pretty small (8K?).

Swap devices should have the highest possible transfer rate since they're
mostly sequential devices.  File systems should have the highest possible
access speed since their access is arbitrary.  Note, however, that as the
worst case seek time approaches the worst case rotational latency time,
rotational latency becomes a significant factor in throughput if all other
things are equal.  Many disks available today have this characteristic.

John Cornelius
Andataco
aka jc%andataco.uucp@ucsd.edu