Even though I have a modern motherboard, for some reason it has an ISA slot on it. So, since I already have 4 IDE devices, I figured I’d get a SCSI controller so that I could add another hard drive. Now, I have experience with IDE drives, but not SCSI, so I have a simple question.
Now this is a stupid question, but I should be able to take this card a face value that it’ll let me use my SCSI 2 controler to run a SCA 80 pin hard drive, right?
I cannot find the specs for the DK319H-18WC drive via a quick search, but a reseller listed it as an 80-pin device. That makes sense, because 50-pin SCSI is very, very old. Now, SCSI-2 means Fast SCSI, and SCSI-3 is Fast and Wide SCSI. SCSI-3 is 68-pin, and new Ultra-2 SCSI is 80-pin. It makes sense the HDD is Ultra-2, so you will not be able to use the old controller with it.
You can almost always step down a drive to work with a slower/older/more narrow flavor of SCSI. I have a 68-pin drive in my PowerMac 7100 which has the plainest and most vanilla of SCSI-1 50-pin ribbon cables plugging into it, thanks to a skinny little adapter.
(You can go the other direction as well but you’ll slow down the responsiveness of your faster bus if you put slower devices on it).
Fairly sure you’re wrong. The Ultra-2 drive, provided that you can find a cabling solution to connect the right 50 pins of the 80 pin connector, should auto-negotiate down to SCSI-2. With SCSI, you can pretty much connect everything with the right adapters and terminators.
Realize, though, that the ISA connector and going down to SCSI-2 is going to greatly dimish the drive’s potential performance.
-lv (who’s made some very ugly SCSI circuits in his day)
Yeah, there are 80 pin to 50 pin adapters: SCSI (80pin, “80 pin”) (50pin, “50 pin”)
So I might go that rout. I’m in no hurry though.
Oh, and what’s a terminator? I only have experience with IDE devices, so I’ve never had to deal with one before. Thanks.
You can mix and match SCSI levels between the controller and disks. The controller and the drive will auto-negotiate the speed and the high byte is generally terminated in the adapter or the cable.
In this case, the 80 pin to 50 pin converter board is only needed because the 80 pin devices are using the hot-swappable SCA interface which has integrated power and drive select lines. If using a native 50 or 68 pin drive, jumpers need to be set for drive assignment (and potentially termination).
See the SCSI Termination Tutorial on the STA website under the section “Connecting WIDE SCA-2 (80 pin) drives to a NARROW bus (50 pin).”