[nSLUG] Re: SCSI novice, hardware qry

bdavidso at supercity.ns.ca bdavidso at supercity.ns.ca
Fri Mar 10 14:49:11 AST 2006


On Fri, 10 Mar 2006, Mike Spencer wrote:
> Okay.  Good.  Goes "between the cable and the device".
>    MoBo-> card -> cable -> external-terminator -> scanner
> Doesn't make intuitive sense but I'll take your word for it.  I'll ask
> at the local computer shops.

Your intuition is correct -- terminators must terminate the chain.  If a 
terminator were on the cable before the scanner, then the scanner would 
not be on the SCSI chain.

Just to clarify your diagram above, it looks more like:

terminator <-> device <-> device <-> ... <-> terminator

where "device" means any SCSI device, *including* the interface card.  You 
will see that many SCSI cards have both internal and external connectors. 
You can visualize this like:

term <-> int. chain <-> card <-> ext. chain <-> term

Now when, say, there is nothing on the external chain, we enable the 
terminators on the card so it looks like:

term <-> int. chain <-> card <-> term

You could also remove the terminators on the card and stick an external 
terminator on the external connector, or on the end of a cable plugged 
into the external connector.

> gnwiii> Try a different cable.  Cables are responsible for 70% of SCSI
> gnwiii> problems...

While George is correct that bad cables cause most SCSI problems, I'm not 
sure that this is your particular problem since you indicated that you had 
problems loading drivers for the cards themselves.  Were I you, I might 
try installing just the card with nothing attached to it and see if I 
could load the driver OK.

I ave an old 1542B and an equally old 1540CF, but no ISA slots in which to 
insert them, so if you want one let me know.  They worked fine the last 
time they were in a computer several years ago.

Bill Davidson
bdavidso at supercity.ns.ca


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