Darren Dunham wrote:
> In comp.sys.sun.hardware "Dave (from the UK)" <see-my-signature@southminster-branch-line.org.uk> wrote:
>
>
>>So it seems this unit (which is an HP drive badged as Sun) has wide
>>SCSI disabled. Will a typical DDS-4 tape drive work on narrow SCSI, or
>>does one has to be a special one?
>
>
> I would expect most devices of proper voltage to work properly on a
> slow, narrow bus as long as the extra pins are properly terminated.
>
> The device should detect the connection parameters and back down to
> match.
>
> I don't know why the Sun part would have a device with the wide SCSI
> disabled in a narrow housing, unless they were expecting it in the
> application and terminated the "wide" pins themselves within the unit.
> (That way your 68-50 pin cable doesn't have to have any smarts).
>

Thanks. This may not be necessary after all. I think I can use a
standard 68-pin tape drive, although that is far from easy.



Having take the Ultra 80 apart and looked at the SCSI in some detail,
what I see is a cable that goes to a disk backplane at one end and the
CD-ROM and the other. I think that cable is probably 68-conductors,
although I have not counted.

Just to make life difficult, there are two problems.

1) The end that goes onto the disk backplane looks as though it can not
be removed. Not sure, but I don't fancy pulling it hard enough to find out.

2) The back of the bit that goes into the CD-ROM has some sort of
terminator. I think that probably terminates the high byte. Again, am
not 100% sure.

I think putting a 68-pin connector on that cable will allow me to attach
a standard 68-pin tape drive, but I'm not over happy about it. The cable
is short, and one end is fixed, so clamping a connector properly looks
to be difficult.

I really need to find out how the tape drive is supposed to be attached,
and if a cable can be bought. I don't fancy messing around with the only
cable I have, given I have not seen one like it before.

--
Dave K

http://www.southminster-branch-line.org.uk/

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