help needed debugging SCSI bus problem

[Matthias Andree]

Joan Picanyol <lists-freebsd-stable at biaix.org> writes:

> ahc0: <Adaptec 2940 Ultra2 SCSI adapter> port 0x1000-0x10ff mem
> cd0: <YAMAHA CRW2100S 1.0G> Removable CD-ROM SCSI-2 device

Nothing more needs to be said.

I have bad experience with both Adaptec SCSI adaptors (1542CF, 2842VL
and 2940UW Pro) and with YAMAHA CD-writers (CD-R 200T, CRW 4416S).

I've never had issues with AMD-based Tekram DC-390.

I've had minor issues with "wide drive on narrow SYM53C875
configuration" (see NetBSD PR kern/6849 for the full round-up -- and
some FreeBSD versions, same problem) that seem to be solved in recent
-STABLE versions.

I do look after two Linux machines with a solid 2940UW setup (the
adaptors are from 1998, one is driving a Fujitsu U320 10,025/min drive)
though, so not all are bad.

My Adaptec 2940UW Pro would lock up every other week. (I wonder if it
would lock with Windows and who'd take the blame, but I'm digressing.)

My Yamaha 200T would go faulty early, it can no longer write disks, but
is fine reading.

The Yamaha 4260S and 4416S had an awful firmware, Yamaha has never been
able to deliver a robust firmware, there's always something that could
lock the driver in a state that might block the whole bus. Don't mount
these into "servers". I wonder if the 2100S fares much better.

I've now replaced the adaptor by a used Tekram DC-390F (15 EUR) and a
new Plextor PX-W4824TA (hum, 119 EUR last winter).

There are Plextor SCSI CD writers available (IIRC the fastest is the
PX-W4012TS) if you want one, but they're around twice as expensive as
their flagship ATAPI CD writer.

I'm sure there are other good alternatives for either component (SCSI HA
and CD writer), but I can only talk about those I know first-hand.

-- 
Matthias Andree

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