>Jim,
>
>>>That's my hope. I just wouldn't be too please to learn otherwise - spending the extra money for virtually no benefit. I'd have confidence with only the new faster drive attached.
>
>I think the main problem you might face with the old SCSI drives is with the cable/drive type (Wide, fast/wide, ultra-wide, whatever) -- something to ask about, cuz I don't know the answers. However, some controllers are "dual-channel", probably meaning that they have 2 SCSI connectors, allowing 2 cables -- one to the new drive, and one to the old ones. That would probably work great.
>

Most HAs have at least two connectors (often 3, of which any 2 can be used at one time). A dual channel HA is actually two independent SCSI channels - controling up to 30 drives (15 drives on each channel, of which 8 must be Wide to use SCSI IDs >7).

>John is right that they work pretty much independently. I would ask, however, about the controller settings for maximum speed (20 mbps, 40 mbps, etc). That MIGHT have to go to the lowest common denominator unless it can be set independently for each drive or channel. In that case a second SCSI controller would work well.

Unless really old (SCSI-1 CCS or earlier) drives are in use, the channel should negoatiate with each device as necessary; in some cases, you might have to force the HA to negotiate with a given device at a lower speed, but not all devices.