Adding New SCSI drive.
18 messages in this thread
OK a Auick Question fer ya Don,
Where is the Denise chip on a rev 6 motherboard. Is it towards the back
center of the board by the cCPU slot. Or is it under the Drive bays?
I was just in there yesterday installing a new HardDrive (Which will
bring me to another question latet 😉 ) and didn't pull the drive bay out,
but I did see a chip that looked like Denise over by the CPU slot. In
other words there was one there by itself and I could replace it with out
pulling the drive bay = Is that it?
Now for the drive Qusetion. I just put in a 105meg on my 2091 control and
for now have take out my original 40meg. I did this because I don't have a
ribbon cable with one connector in the center and one on the end. When I
do get that cable I'll reinstall the 40meg. For now, let my just review
with you what I'm going to do and you can tell me if its right. With that
cable I will attach one end to the Controler Card, the middle connector to
the 105 installed on the card, and the end to the 40 installed in a drive
bay. I will pull the terminators on the 40 (there are 3 of those little
back things at the back of the drive) (Opps forgot to check last night if
the 105 had terminators or not). Now, how do I change the Address of the
drive – it was 6 but now the 105 is 6, I will have to change the number of
the 40 before I put it back in. Are those the jumpers on the back side of
the drive?
Hmmmm. I hopin' you (or someone else) have knowledge of the old Quantum
40meg to know which jumpers to move to set the address to 5 or somethin'
Thanks.
– Roy Pahnke – Casper, Wyomin'
Roy,
No idea where it is on a Rev 6 motherboard. I'd suspect it's still
back by the RGB port like it is on the Rev 4 motherboards. It's an 8362,
or at least that's what my old Denise was (in particular Rev 8…so
8362R8). It should have the MOS logo on it.
The terminators go on the LAST drive on the bus…so under your
proposed setup, you'd end up with NO terminators on the 105, and
terminators on the 40.
Yes, you'll have to change the SCSI ID on one of the drives, I'd
change it on the 40 Meg….it doesn't matter what order devices sit on the
bus relative to what SCSI ID they have.
I don't know where the ID jumpers are on the 40, but it's fairly
easy to figure out generally. Since it's set at 6, there'll be a set of
jumpers that looks like this somewhere near the back of the drive:
X == jumper pin | == jumper
X X X
| |
X X X
The jumpers will probably be labeled "a0", "a1", "a2", or "d0",
"d1" , "d2" or some such. They may be sitting by themselves, or they may
be in a string with other jumpers, but it should be obvious from their
labels that those three are related. Just move the jumper next to the open
pins onto those pins so that it ends up looking like this:
X X X
| |
X X X
That'll set it to ID 5.
Don
Don –
Thanks for the advice on the Denise label – I'll look for the 8362.
You were right on with the discription of the jumpers on the 40meg.
Looking at my drive now I can see the set of 3 labeled A2 A1 A0. My
jumpers are now set on the 2 left jumpers (just like you said) and I'll
move the center on all the way to the right jumper. Thanks, thats exactly
what I needed to know.
Now all I have to do is get the cable, and knowing this town – I may
have to order one down from Denver 🙁
Be readin' ya.
– Roy Pahnke – Casper, Wyomin'
Don,
I am getting multiple hard drive crashes. This is while adding a SCSI
tape drive. The cable has a center plug that is 6 inches away from the
internal drive, then going to the external Tape drive is 5 feet of cable.
Both ddrives are terminated OK but really trash my hard drive needing to
do a complete re-format. I know the Trumpcard Pro can be sensitive to poor
cables but can this imbalance cause such behavior?
When I use a balanced cable it works flawlessly. What should I look for
or change?
Paul
–pt–not seattle– 😉
Paul,
The answer is right there in your message, where you say "both drives are
terminated"
Only the drive on the end of the cable should be terminated.
When the termination is not right, operation can range from good to
intermittent, to no operation at all, and yours is the classic case of
being right on the edge, where small changes in cable length make a big
difference. If you remove the termiinators from the card closest to the
internal, it should work just fine.
-larry
Larry and Don,
I thought the SCSI setup needs to be terminated at both ends, not just
one. I have the controller in the center of the chain, no terminators, and
then the cable comes off the TrumpCard and goes to the tape drive and
stops. Then from the second connector on the TrumpCard a new cable goes to
the HardDrive, stopped and terminated.
During the backup process, tape to hard drive, everything freezes with
both drive lights on. Can this really wipe out all the info and RDB? The
formating software can't find diddley on the drive and I have to do a
floppy re-install and partion rebuild.
Thanks for the help 🙂
Paul
–pt–not seattle– 😉
Paul,
When something goes wrong on the SCSI bus, the results can be anything
from innocuous to catastrophic. It depends on what's happening. Though the
RDBs are not being accessed during a backup, it is quite easy to see how
they might be clobbered, should the drive writ to block 0, since block 0 is
the 'base' of the RDBs, and without it, the controller will think the drive
does not have RDBs at all.
Yes, the SCSI bus should be terminated at both ends. Usually, the host
adapter is terminated, and if it is at one end of the chain, you need only
terminate the other end. With the host adapter in the middle, if you
terminate both ends of the bus, you will have three termination points, and
things can get loaded down. Under these circumstances, the SCSI bus will
often work with shorter cable lengths, and fail with longer ones (this is
what gives SCSI termination a bad name).
The answer in your case, I believe, is to ensure that only the ends of
the SCSI bus are terminated. This can be accomplished in a few ways:
1. Daisy-chain the tape and disk, so that the host adapter is at one end of
the cabling.
2. Leave it as is, but remove the terminators fromn the host adapter (may
or may not be possible; I am not familiar with the TrumpCard).
Often, one of the drives will be internal (yes, the internal one is on the
same bus\, even if it's hooked to a fifferent connector). If the cable run
is short enough, you can often get away with leaving it untermninated.
According to the SCSI spec, you are allowed 'stubs' of not more that 10
cm., and experience has shown that if the total cable run is not too great,
you can get away with longer stubs.
I think you are on te verge of getting things fixed up. Good Luck.
-larry
Paul,
You say you have the host adapter in the middle (which is fine)
with no terminators. Does this mean that the host adapter has removeable
terminators on it…or that you've got a drive on the host adapter and
you've removed the terminators from it?
Don
Don,
The host has removable terminators, and they are out. The drive is on
the host adapter and it has soldered in terminators. There is a command in
my tape backup software that has a "Synchronous/Asynchronous", this may be
useful.
Sorry for the delay in this reply, I'm just barely able to keep things
afloat between crashes.
Is there a way I can turn off re-selection if my host software has no
provision for it?
Thanks for the help,
Paul
–pt–not seattle– 😉
Paul,
No drive manufacturer in their right mind would solder in the
terminators. The in-line type of terminators may appear to be soldered in,
but they are in fact socketted.
I know of no way to turn off re=selection if your software does't
support it.
I'd try the async setup on the tape.
Don
Paul,
I agree with Larry. Only the drive on the end of the cable should
be terminated.
Don
Roy –
I recently did something similar to what you are doing, except that I left
my Quantum 40meg on the 2091 and installed a Maxtor 120 meg in a drive bay.
You want to leave the terminators _on_ the last drive in the SCSI chain.
Therefore remove the terminators from the 105, and leave them on the 40, if
the 40 is on the end of the cable. The drive you boot from should have the
lower SCSI ID number. On the Quantum 40 I have, the ID number is set with
3 jumpers (A0, A1, and A2, I believe) as a binary number with a 1
indicating jumper set and a 0 indicating jumper disabled:
1 1 0 – 6
1 0 1 – 5
1 0 0 – 4
0 1 1 – 3
0 1 0 – 2
0 0 1 – 1
0 0 0 – 0
Hope this helps.
Jeff Schweiger
Thanks Jeff –
I'm going to leave the 105 on the card (will take of the terminators)
and put the 40 in the bay. When the 40 is back in I'll probably let it be
my Boot/Workbench drive (Do you think one partition – 40megs will be enough
for Workbench 😉 ) So that will mean I set it's id to a lower number –
Yours is set to 3, but 5 would do too (right).
Anyway – I'll looking forward to the room. Previously I had this drive
partitioned off with a 5meg Workbench and 35mer Work space. With that set
up things were getting really tight. Now I'll have lots of room for fonts
and my C: like stuff (which I like to put in a separate C directory from
Commordore's C:) and finally lots of space for the S:
Meanwhile the 105meg with be my Work: drive and I'm sure I'll have
enough room there to last me a year or two. 🙂
Now to get a tape drive, these backups will start to get lengthly with
just dual floppies 🙁
– Roy Pahnke – Casper, Wyomin'
Jeff –
Do you know why the booting HD should have the lower SCSI ID number? I
have a 3M MCD tape drive at ID 3 and my 40MB Quantum at its original ID 6.
I have been having trouble getting the tape drive to work properly; but, I
have not had any problems with the hard disk.
– Nelson …
– via Whap!
Nelson –
I don't have the specifications, but the controller looks for a bootable
device in increasing order. It's possible that tape drives are skipped
because they are non-bootable. Don or one of the others who are somewhat
more knowledgeable may be able to better answer your question.
Jeff Schweiger
When I have had tape drives in the past, I have had them set at 0, 4, and
2. If you run HDTOOLBOX, it notes that it is a non-booting device, so one
assumes that the Amiga boot sequence also notes the same thing. If I
understand it correctly, SCSI allows querying the type of device.
Jeff,
Generally…it works the other way….looks for the device with the
highest boot priority in decreasing SCSI ID. The logic is that SCSI
assigns higher priority to higher SCSI ID's…thus you want to boot from
the highest priority device.
I *believe* it can be overridden via the BootPri setting in the
RDB.
Don