"David W. Chapman Jr." <[EMAIL PROTECTED]> writes:
> On Mon, Jun 17, 2002 at 04:19:49PM -0500, John Prince wrote:
>> Hello David
>> >Is this the only other problem?
>> I think instead of asking is this the only problem, we should be saying
>> "How does this impact our existing Users?"
>
> And we can't get a full scope of how it is affecting our existing
> users until we have a list of all the problems.
ATA-related problems I am aware of:
Known Problem: IBM DTLA-307045 (75 GXP series) + VIA 82C686 south bridge
("KT133") locks up on TCQ, times out and falls back to PIO. (I cannot
try my onboard PDC-20265R because FreeBSD avoids TCQ on this chip.)
Works, but slowly. 4-STABLE before MFC was fine in UDMA/66 with
"TAGGED".
Compatibility: (already reported) Linux 2.5 ATA ships with working
tagged command queueing on Western Digital AC420400D (which looks like
an IBM DJNA-352030 clone). FreeBSD does not dare use TCQ on this drive,
and as I hacked up 4-STABLE in spring to try it, it locked up. (I have a
dual-boot FreeBSD/Linux machine, so no worries about differing
hardware.)
Performance: Linux 2.4 and 2.5 ATA sub systems have higher troughput on
sequential read than FreeBSD 4.6-RC ATA. Never looked for latency
through the file system (and cannot, as the Linux 2.4.19-pre BSD FFS
file system is hosed.)
(OTOH, FreeBSD 4.6-RC SCSI -- at least the aic stuff with an Adaptec
2940 UW Pro -- has better throughput than Linux with my U160 drive.)
--
Matthias Andree
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