SCSI questions (1 Viewer)

[Keith Mickunas]

I've got a Dell P2-400 that I got from my current employer 3 years ago, it was probably 1 to 2 years old at the time. Its got a SCSI drive in, 8GB I believe, running off an Adaptec controller. Its at home now so I don't know if its 68-pin or 80-pin, my guess is 68 as the cable is fairly small, and I think it was some form of SCSI-2. A friend is hooking me up with a current Seagate drive. Can anybody tell me whether or not SCSI is backwards compatible? Or will I need a new controller? I know, I'm not providing much information, but I'm just curious how much the SCSI spec has changed over the past few years.

 

[DonRoeber]

SCSI will slow down the whole bus to be as fast as the slowest device on the chain. So, you should be fine.

 

[Keith Mickunas]

I've taken a look at the card and found the following on it: AHA-2940UW Dual/NE
Its got two internal connectors on the card, and one external. It appears that the two may be of different size, but I haven't taken it out of the case yet to examine it closely. The one that is in use is a ribbon cable that is slightly narrower than a standard IDE cable. Anyone know how many pins that might be?

 

[Keith Mickunas]

Well the controller supports SCSI-1, SCSI-2, SCSI-3, WIDE UltraSCSI and has 68-pin and 50-pin connectors. I see that 80 to 68 pin adapters exist. Now it looks like the current Seagate SCSI drives are all Ultra320, anybody know if that is backwards compatible with SCSI-3. It looks like Ultra160 is, I hope that Ultra320 is also.

 

[Glenn Overholt]

If you're thinking about buying a 320 drive and using it with your controller, forget it.

If you're thinking about buying a 320 conroller, you might want to look in your wallet first.

Glenn

 

[Keith Mickunas]

Well the drive is free and I think it'll be 320, I'll find out next week. So I'm hoping it'll be backwards compatible with the controller. But I just can't find anything that says one way or another. Seagates FAQs cover 160, and I think they say it is backwards compatible. I can only hope the same is for 320. Otherwise I'd be better off giving the drive back and buying IDE.

 

[Steve_Ch]

You may want to just go to Adaptec's site and see what's there (in so far as compatibility) FWIW, the 2940 series of SCSI controllers were extremely popular, kind of the "standard" at the time, looks like you have the Ultra Wide variant.

 

[Keith Mickunas]

I found the specs at Adaptec and it looks real good, it'll do SCSI-1, 2, 3 and wide UltraSCSI. But what the hell is all this Ultra160 and Ultra320 crap? I long for the days of SCSI-1, SCSI-2, and so on. Then they added wide and ultra wide and super absorbent, and whatever else their marketing departments come up with. Its like trying to keep up with different branding for Firewire. But at least most people reference IEE-1394 to keep that straight.

Well I found that Adaptec's Ultra320 cards are backwards compatible and have 68-pin connectors, however they have separate 68-pin connectors for Ultra320 and older SCSI.

I found a press release at seagate saying their Ultra320 drives are backwards compatible with Ultra160, and the specs on Ultra160 drives state compatibility with older SCSI interfaces. That could be a good sign.

 

[Ken Chan]

Check out SCSI Protocols and Transfer Modes. Other topics there should explain narrow, wide, LVD, etc.

//Ken