How fast are your disks?

[Tim Bray]

In a recent meeting we were analyzing the performance of this application that
is rather I/O bound - in particular, it performs a lot of very random accesses
here and there in large (> 100 Mb) files.  Somebody said "Now, we'll assume
that Unix can do a maximum of 30 disk I/O's a second".  Somebody else remarked
that that figure had been remarkably constant for quite some time.  Somebody
else proposed that it was a fundamental law of Computer Science.  (Of course,
we are poor peons restricted to the use of Vaxes and Suns).

Anyhow - Presumably there are other people out there limited by this
particular bottleneck.  Are there reasonably-priced unix systems out there
that do better?  Are there a set of benchmarks which reliably characterize
system performance in this area?

To address this problem, I half-seriously propose a new metric: Application
Disk I/Os per Second, named, obviously, ADIOS.

Adios, amigos.
Tim Bray, New Oxford English Dictionary Project, U of Waterloo, Ontario