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From: sos@login.dknet.dk (S|ren Schmidt)
Message-Id: <9503221424.AA12175@login.dknet.dk>
Subject: Re: Why IDE is bad
To: bde@zeta.org.au (Bruce Evans)
Date: Wed, 22 Mar 95 15:24:27 MET
Cc: phk@ref.tfs.com, faq@FreeBSD.org, hackers@FreeBSD.org, hasty@star-gate.com
In-Reply-To: <199503221305.XAA14540@godzilla.zeta.org.au>; from "Bruce Evans" at Mar 22, 95 11:05 pm
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> 
> >And that is the main thing on E-IDE, the drives are designed
> >with enough onboard cache, that coretest etc. reports transfer
> >rates close to the interface speed (13MB sec or so), but the
> >drive cannot hold this speed when it has to read from the media.
> 
> This is also good for reducing interrupt overhead.

Hmm, most of the drives would intterupt once each sector anyway
even when doing DMA, so there is really nothing gained...
 
> >And here is the catch, in that most el cheapo IDE drives has
> >inferior drive mechanics (hey they are cheap), and then some
> >fancy cache/interface electronics to make up for outdated
> >hardware....
> 
> I expect better IDE drives would have been avaiable if the
> interface had supported them.

Actually I think not, the IDE thing is about making CHEAP disks
for the average PC user. It is much better advertising to have a
500MB drive than a 300MB drive, who cares about performance ???

So we will get bigger/cheaper IDE drives, sure, but "better"
nah, that doesn't sell hardware to Joe Random User....
We in the *nix world are very atypical PC users, who CARES about
performance, but we will also have to pay the price for it. As
a vice man once said "there is no such thing as a free lunch"...

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Soren Schmidt  (sos@FreeBSD.org | sos@login.dknet.dk)  FreeBSD Core Team
               So much code to hack -- so little time
..