[Coco] SCSISYS question

[Gene Heskett]

Bob Devries wrote:
> Does anyone here use SCSISYS 2.2 with two SCSI drives?
> I have been trying to add a second drive as a backup unit to my system, 
> but having no luck at all. The system just locks up when I try to access 
> it using SCSIFMT. Even if I build a descriptor using SCSIDESC, I cannot 
> access the drive.
> 
> Gene, do you have any ideas on this?
> dmode /h0 gives:
> drv=00 stp=00 typ=84 dns=80 cyl=0385 sid=05
> vfy=00 sct=0035 tos=0035 ilv=05 sas=08
> 
> dmode /h1 gives:
> drv=01 stp=00 typ=84 dns=81 cyl=0385 sid=05
> vfy=00 sct=0035 tos=0035 ilv=05 sas=08

In the dns=81, what does the 1 do?  I've forgotten.

> Both drives are Quantum Prodrive LPS-120S. One drive has no jumpers, and 
> the other has a jumper on A0. The terminator resistor is removed from 
> the first drive on the cable (H1).
> 
> Have I overlooked something? H0 works very well, and is giving 11 
> secs/MB with megaread on NitrOS9 V030206.
> H1 lights up its LED, but then the computer locks up. I can (usually) 
> switch windows, but can't type commands.

That essentially duplicates the experience I had, Bob.  My drives were 
not alike, but I wasn't able to do a 2 drive setup at all using 
scsisys2.2 and a disto 4n1.  Any attempted access to the second drive 
resulted in a locked up system.  Like you, I recall I could switch 
windows, but that was about it.  My second drive was also a quantum 820 
megger, first was a maxtor 7210s (130 MB)

I was told at the time, but don't recall who said it, that the 34 wire 
scsi implementation of the disto 4n1 resulted in some signals required 
for multi-drive access weren't there.  The disto used a 34 wire floppy 
cable, split down the middle so it picked up the outside 17 wires on 
each end of a std 50 pin scsi connector. Among the missing signals was 
term power on pin 26, so it was required to have the drive supply its 
own term power.  That might be a clue, but off hand if the terms are 
removed from the 2nd drive, there might still be a need for term power 
in order to power the cable interface chips on that 2nd drive.  Is that 
jumper set on the 2nd drive?

I can't think of anything else atm cause I didn't ever make it work 
either, sorry.

I was able to use the quantum on my big box amiga for a few months, but 
it eventually silently self destructed.  I didn't use it a lot, and I'd 
put some stuff on it to get it out of the way on the main drive at the 
time, a 1GB seagate Hawk.  I have 2 of those, both seem to be 
indestructable as one of them is now on my coco3.

-- 
Cheers, Gene