[SunRescue] NetBSD 1.4 miniroot problem fixed

Martin Frost martin at dsres.com
Wed Dec 8 12:23:32 CST 1999

Tim Hauber wrote:

> Well, SCSI is nice, in theory, but even newer stuff can have
> cable quirks.

In my experience SCSI problems are usually with whatever was
pushing the limits at the time it was built. If you think that
sun3 SCSI is bad, try Macintosh Plus SCSI. It didn't help that
the SCSI support was made using the very first NCR SCSI chip,
that the spec was still being changed, and that no dedicated
connectors had been designed. It's reliable enough with its
contemporary external disk boxes, but just about nothing else.

IMHO, the reason SCSI gets a bad reputation is that it's been
the only bus available for external disk connections for some
time. As many people have noted in this thread already,
strange reflections and interference cause all sorts of
problems with fast buses (and remember that modern SCSI
is clocked at up to 40MHz: that's really quite fast for a
bus that can be several feet long). All the other buses just
give up and support only one or two devices on a much shorter
bus, which is a lot easier.

Who was it who said that `SCSI is the second worst IO bus
ever invented, but all others tie for first place'?

ObRescue: For all its faults, rescuers of old hardware
owe a great debt to SCSI: it means we can still buy disks
that will (in general) still work with our old systems
(since disks and tape drives are the least reliable parts
due to their moving parts, this is a Good Thing).


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