🚀 go-pugleaf

tls@cloud9.net (Thor Lancelot Simon) wrote:

>The Atlases I have seem pretty quiet, and reasonably cool.  The Ultrastar 
>DFHSes I have are quiet, but run rather hot.  I don't know about Fujitsu 
>drives in that regard; I have a few 32550N 2GB Barracudas which run 
>(modulo being in rackmount cases with huge huge fans on both sides) very 
>cool, and are quiet enough that at least over the fan noise (not really 
>so bad, with the case in question) I can't hear them seek.  For some 
>reason, though, I always get lousy write performance with the Barracudas; 
>I've noticed this several times.  Does anyone know if there's a mode page 
>bit that might be mis-set for many applications by default?


Yes.  Many SCSI drives come with internal write-caching turned off.
This probably won't dramatically improve long sustained writes of very
large files, but it can make a dramatic difference for most every
other write situation.

The problem is finding a program to change the mode-select parameter
that controls this.  If you have an Adaptec 154x or 174x compatible
card, Roy Neese's SCSICNTL might work.  I think many Unix OS's have
built-in ability to send SCSI commands directly.  But the best I've
found is Matt Thul's utility MSDU, that is if it's a publicly
available product by now.  (Actually I believe even Adaptec's EZ-SCSI
now comes with a utility that only toggles write-caching and does
nothing else)


Phil
pjk@aimnet.com
pjk@netcom.com