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Date:      Thu, 4 Apr 1996 15:32:37 +0930 (CST)
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        Brett_Glass@ccgate.infoworld.com (Brett Glass)
Cc:        msmith@atrad.adelaide.edu.au, jkh@time.cdrom.com, hardware@freebsd.org
Subject:   Re: Some solutions to disk problems.... I think.
Message-ID:  <199604040602.PAA25320@genesis.atrad.adelaide.edu.au>
In-Reply-To: <9603038285.AA828550952@ccgate.infoworld.com> from "Brett Glass" at Apr 3, 96 09:29:25 am

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Brett Glass stands accused of saying:
> 
> >> In this case, it's easy to enlarge. Just expose per-drive flags as well
> >> as per-controller flags.
> 
> > That's not possible; the drives aren't visible until after they're
> > probed,
> 
> Controllers are visible before they're probed. Why not drives? We know that
> an IDE interface can have at most two.

*sigh*  The whole point is that _nothing_ other than the 'wd' driver
should know this; it needs (and for the most part has) no special-case
code.  Adding such code would be bogus in the extreme.

> > A simple wildcard matching routine would handle this sort of thing.
> 
> The patterns would require some complex matching.

You want to be able to match a vendor string and a model number.  If the 
textual content changes, you duplicate the entry in the table.  It's
nice and easy, and right where you can see it.

> > The excess of functions duplicating essentially the same functionality
> > makes it very difficult to see, at a glance, what is being searched for.
> 
> Different things will be searched for in different cases. It's easy to
> break this out into functions that search for the right thing in each case.

Huh?  You can "search for" the contents of the ID string.

> I've seen the SCSI rogue detection code. The difference is that SCSI IDs
> are much more constrained by standards than IDE/ATA IDs. And here, we're
> not really talking about "rogues;" we need to know the right thing to do
> for EVERY drive we handle. This makes the table much bigger than if it only
> handles exceptional cases.

No, egregious monsterism aside, the majority of drives still follow the 
spec.  All you want is a list of drives that behave outside the envelope
that's required for conformance with the driver.  This is not 'all drives',
as is demonstrated by the lack of such a table to date.

> --Brett

-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
]] Genesis Software                     genesis@atrad.adelaide.edu.au   [[
]] High-speed data acquisition and      (GSM mobile) 0411-222-496       [[
]] realtime instrument control          (ph/fax)  +61-8-267-3039        [[
]] Collector of old Unix hardware.      "Where are your PEZ?" The Tick  [[



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