Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!milano!bigtex!james
From: james@bigtex.cactus.org (James Van Artsdalen)
Newsgroups: comp.unix.sysv386
Subject: Re: Additional IDE support? (was Re: Interactive 2.2.1 Upgrade)
Keywords: interactive unix upgrade posix ide
Message-ID: <53064@bigtex.cactus.org>
Date: 18 Jan 91 07:00:00 GMT
References: <1991Jan9.140259.25395@ux1.cso.uiuc.edu> <1991Jan09.172325.715@nstar.rn.com> <1040@mwtech.UUCP>
Reply-To: james@bigtex.cactus.org (James Van Artsdalen)
Distribution: comp
Organization: Institute of Applied Cosmology, Austin TX
Lines: 21

In <1040@mwtech.UUCP>, martin@mwtech.UUCP (Martin Weitzel) wrote:

| there is no "fix" perse in this latest release. Technical support
| stated the following as the 2.2.1 fixes:

|	*  Additional IDE support for Seagate and Rodime

> Weren't all the people telling all the time that an IDE device looks
> exactly like and standard disk controller (ST412/ST506) to the rest of
> the system?

For some IDE drives, AT compatibility is only an "approximation"
concept.  There are drives that yank the IRQ before the data is in
fact ready (heck, the interrupt handler is bound to take a while
before reading the data).  Also, I am told that some drives fail to
assert IOCHRDY in order to guarantee minimum time between buffer
accesses - they simply "know" that no system can do REP INSW with less
than 500ns per.
-- 
James R. Van Artsdalen          james@bigtex.cactus.org   "Live Free or Die"
Dell Computer Co    9505 Arboretum Blvd Austin TX 78759         512-338-8789