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- SCSI question
July 8, 2005, 1:29 am
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Re: SCSI question
Not necessarily. I actually think the IDE ones are the exception.
For context here, I've spent most Saturdays recently tearing down old
computers for recycling. We've dismantled several 1997-99 era servers in
the last couple of weeks and are salvaging some of the drives for shop use.
I came into this knowing very little about SCSI and the equipment has been
teaching me a thing or two.
I've seen fat bulky drives and slim pretty ones all labeled "Barracuda," so
it's not so much a specific model as a name for their higher-quality line of
I've been seeing three kinds of SCSI connectors (and I've seen Seagate
Barracudas in all three types).
There's a fifty-pin connector that looks like an IDE connector but wider,
and occasionally a fifty-pin micro connector, with a molex for power like
IDE drives also. These are labeled N for Narrow (i.e. model number
ST15150N) and I think that corresponds to SCSI-1. They have an 8-bit data
There's a 64-pin micro connector that also has a molex plug for power.
These are labeled U, W, or UW for Ultra, Wide, and Wide Ultra. Ultra refers
to transfer speed while Wide refers to a 16-bit data bus, and the drives can
be either or both.
The third kind I've seen has an enclosed card-edge connector that
facilitates hot-swapping and incorporates the power wires with the data
plug. They are labeled "Ultra 3."
It's my understanding that SCSI drives are all compatible if you have the
appropriate adapter, but adapters might be hard to come by and will give you
the performance of the device on the slower side of the adapter. You want
to locate drives that have the same connector type as the drive you're using
now, probably the 64-pin ribbon type. But you can't go by brand name
alone, and model numbers can be identical except for the suffix N, W, UW, or
U3 (and there might be others I haven't seen). I think you would have
difficulty using the U3 type, but in general if it fits your ribbon it will
run on your adapter.
I use an Adaptec 2940UW PCI adapter, which has connectors for the big 50-pin
cable and the slimmer 64-pin cable. At one point I had two 8-GB drives on
the UW cable and a 4 GB hard drive and CD-ROM on the Narrow cable all at
once, and they all worked.
Last Saturday I connected an 18.2GB UW drive to a U3 shuttle by means of two
adapters, with the 50-pin connection in the middle; but watch this space,
because I don't know yet whether or how well that works.
Re: SCSI question
Today I picked up a drive from the pile and it had a similar 80-pin
connector. I knew they existed but hadn't seen one, presumably because
people aren't retiring and recycling them yet.
For what it's worth, this didn't work. The adapter reported no drive
connected. Fifty-pin narrow drives with a single adapter to the U3
connector did run, however.