Any SCSI experts here?!

jebusmusic

Hi, hope someone can help me out.

I have an Adaptec AHA-3944 SCSI I/O PCI Card (http://cgi.ebay.com/Adaptec-AHA-3944AUWD-PCI-HVD-Diff-SCSI-Adapter-Card_W0QQitemZ160142168607QQihZ006QQcategoryZ31494QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)

and an external SCSI Exabyte Drive EXB-8500 (manual here http://www.exabyte.com/support/products/getmanual.cfm?id=275)

They are both HVD devices.

What kind of cable do I need to connect the two of these together, using the external connections of both?

They both appear to be 68pin but are different sizes, the card connector is a lot smaller than the Exabyte.

I'm not bad with PC's, but SCSI wrecks my head and I know nothing about it, so any help would be much appreciated!

And also, I'm aware that bothe these units are very old and bad, but it's a work related thing, and there's literally no other choice.

trout

Can't claim to be a SCSI expert ... but I have been playing with SCSI devices for many years, including Adaptec devices.

I suggest you go here ->

http://www.ramelectronics.net/html/scsi_connecters.html
http://www.ramelectronics.net/html/scsi_help.html

Identify the exact physical connectors you have on your card & the tape device, and that should help identify the cable required... (VHDCI 0.8mm HPCN68 male to HD68 Female ... you get the idea)

Good luck ... let us know how you get on.

jebusmusic

Thanks for that trout, very helpful.

Going by that webpage, it appears I need a HD68 Male to VHDCI Male cable, such as this; http://cgi.ebay.com/SCSI-Cable-VHDCI-Male-to-HD68-Male-3-Feet-Long-New_W0QQitemZ230156164229QQihZ013QQcategoryZ31494QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

What I'm wondering now is about the LVD/HVD thing. I know using a HVD device with a LVD card for example would damage the equipment, but are the cables LVD or HVD, or just a cable?!

trout

I believe the devices are either HVD or LVD, and the cables are just cables. (HVD being the older technology)
If the cables are of a low grade, or too long you can get intermittent errors and poor transfer rates.

If all you want to do is connect the SCSI card to the Exabyte unit, and you know both are HVD ... I can't see how you'll damage the devices with the wrong cable. (HVD and LVD refer to the voltage differential for the signals ... doesn't mean that the older units are all High Voltage)

All I can foresee failing are termination on the Exabyte, or comms between the devices over the cable.

You are right to be cautious ... but I think the danger is trying to mix & match HVD/LVD devices, particularly if you are chaining.

Have you found a cable with the correct ends ?
Is this cable rated or better yet, does it have a part number ?

If it was me ... I'd try out the cable, but with any important media removed from the Exabyte... but that's just me.

Good luck:)

Capt'n Midnight

I'll never forgive the SCSI standards bods for shooting themselves in the foot on connectors. Why do we need N+1 different connectors when the cables all cost ten times what an IDE cable costs. And at that price why do we have SO MANY PROBLEMS WITH CABLES ???

Also with N+1 cables why did they reuse low voltage cables with high voltage devices ??
Yes the cables are exactly the same - so you just can plug an expensive tape changer into an mission critical server that you can't afford downtime on.

SCSI ain't much for home users, and since many SCSI drives are just IDE drives with different motherboards I can't see how they can charge so much more

It's got to the stage where I'd open up external SCSI devices and put them in an internal bay and use the internal 50 pin or 68 pin connector on the back of the device.

/RANT