scsi2 host adapter

[meckerle]

I just installed an adptec scsi2 card model ci-2020m so I can hook my zipdrive plus directly. I have problems. First when I boot up I get this message on the dos screen: "Host Adapter Failure". Also, the zip drive is no longer recognoized as it was when I had it hooked to the parallel port with my printer. I have been told that the zip drive must be "terminated". What does that mean and how do I do it? Appreciate any help. Thanks, Marty

[Danzego]

Well, I guess a crash course in SCSI is what you need. Whether or not this fixes the problem you're having remains to be seen. Basically a SCSI chain consists of two separate chains: one internal, one external. When you hook devices up to a chain, the card keeps looking all the way to the last device. Problem is, it doesn't know what the last device is unless you tell it. This is done by "terminating" the last device in the chain, which enables the SCSI adapter to know that it is the last device in the chain and it need not look any further for additional devices. For an internal device such as the Zip drive, setting the termination is as easy as placing a jumper over the pins marked "T" or "terminate" (or some variation of that). If you later add more devices to that chain later on, you probably would choose to take off the termination on the Zip drive and place it on the other device as physically, the Zip drive is lowest in the case (unless of course you have a desktop case or have the 5.25" faceplate on the Zip drive). Whichever device is closest to the end of the ribbon cable opposite the adapter is the one terminated, in short. Externally, you would do the same thing, except termaination is usually done by placing a SCSI terminator (which looks like a port adapter) on the device furthest from the host adapter. If you're using the adapter that came with the Zip drive you wont have this problem as it doesn't have an external port (if memory serves). If it does and you have no external devices, you must set the adapter to terminate so as to let the adapter know there are no external devices to go looking for. Termination on a host adapter is usually done with a jumper on the board, in the SCSI BIOS, or the adapter recognizes there is nothing hooked to the external port (same goes for having only external devices and no internal). Another thing to remember is each SCSI device must have its own ID number. You can't have two internal or external devices with the same ID, but you can have an external with the same ID as an internal one (as the adapter is looking in different directions for devices. Just keep in mind that ID 7 is reserved for the SCSI card itself and ID 0 is usually the first device in the chain. Just set the ID to 3 to play it safe (you shouldn't have a problem). Sorry 'bout the long post, but I'm just making sure you know how SCSI works and not just giving a quick fix so you may run into other problems. There are a few more things I can go on about, but that should give you a basic understanding of SCSI and an idea 'bout how to fix the prob.

[meckerle]

Thanks for the detailed reply. I must the a "terminator" before I do anything.
Marty