[rescue] Old sci and ide drives

[Nathan Raymond]

On Mon, Mar 13, 2023 at 2:39 PM Mouse via rescue <rescue at sunhelp.org> wrote:

> My experience is that all the way from async narrow up through U320,
> you can mix-&-match and it will Just Work (though in some cases the
> fast device will slow down to match other things on the bus).  The one
> except I've run into is that high-voltage differential is not
> compatible with anything but other HVD.  Other than that, it doesn't
> matter - async, sync; narrow, wide; slow, medium, fast, ultra; the
> worst that happens when you mix them up is that it runs at the slower
> speed.
>

The one exception I discovered is that if you take a wide SCSI device and
hook it up via a narrow (non-wide) connection to a SCSI host which is also
wide, then the SCSI bus will just appear to lock up, because I believe both
the device and host are attempting to handshake/talk across the wide bits
of the bus that aren't connected. I seem to recall some small minority of
SCSI drives which had an extra jumper to force them to operate in a narrow
mode, which would let them function in this situation.

- Nate
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