SCSI ID on tape drive

[SteveW]

Hi,

I've just got a replacement tape drive for my w2k server. I am new to SCSI
config, and I don't understand about SCSI ID numbers. Should I set the new
tape ID to be the same as the replacement? Or should it be different?

I am a bit confused because the ID of the old one was 0, and the ID of a
SCSI disk in the server also appears to be 0. Do I need to confirm this, if
so which is the best way to view the SCSI IDs? I was looking in Device
Manager.
I can give the new tape drive an ID from 0 to 15. Does it matter what the ID
is as long as its unique?

Thanks
Steve

 

[Rick]

Hi,

I've just got a replacement tape drive for my w2k server. I am new to SCSI
config, and I don't understand about SCSI ID numbers. Should I set the new
tape ID to be the same as the replacement? Or should it be different?

I am a bit confused because the ID of the old one was 0, and the ID of a
SCSI disk in the server also appears to be 0. Do I need to confirm this, if
so which is the best way to view the SCSI IDs? I was looking in Device
Manager.
I can give the new tape drive an ID from 0 to 15. Does it matter what the ID
is as long as its unique?

1. All SCSI IDs on the same SCSI controller channel must be
unique. It's possible the server's hard disks are on a separate
controller, or channel.

2. ID's can usually be changed without causing any problems.

3. Traditionally on servers, SCSI IDs 5 and 4 are reserved for
tape drives.

4. If the tape drive is not a SCSI Wide device (i.e. 50 pin port
instead of 68-pin), ID's lower than 8 must be used (7 is usually
reserved for the controller).

Rick

 

[SteveW]

1. All SCSI IDs on the same SCSI controller channel must be
unique. It's possible the server's hard disks are on a separate
controller, or channel.

2. ID's can usually be changed without causing any problems.

3. Traditionally on servers, SCSI IDs 5 and 4 are reserved for
tape drives.

4. If the tape drive is not a SCSI Wide device (i.e. 50 pin port
instead of 68-pin), ID's lower than 8 must be used (7 is usually
reserved for the controller).

Rick

Thanks a lot, Rick for your help. I'll give it ID 5. Yes, the tape and the
disks are shown as on separate controllers in device manager. The
controllers have the same name, but a different function number in
"Location" on the Property page.

Regards
Steve

 

[Mike Brown - Process Manager]

Hi,

I've just got a replacement tape drive for my w2k server. I am new to SCSI
config, and I don't understand about SCSI ID numbers. Should I set the new
tape ID to be the same as the replacement? Or should it be different?

I am a bit confused because the ID of the old one was 0, and the ID of a
SCSI disk in the server also appears to be 0. Do I need to confirm this, if
so which is the best way to view the SCSI IDs? I was looking in Device
Manager.
I can give the new tape drive an ID from 0 to 15. Does it matter what the ID
is as long as its unique?

Thanks
Steve

I would also add to Rick's good information, that 0 does not always equal 0.
On most drives, if you jumper ID bit 0, you're actually using ID 1. If your
jumpers are numbered 1, 2, 4, 8 then they are numbered in decimal (pretty
rare, but I've seen it.) If your jumpers are numbered 0, 1, 2, 3 then they
are numbered in binary. You're actually jumpering the one, two, four, and
eight IDs.

Hope this didn't hurt more than it helped


--

Mike Brown
Process Manager

Asset Forwarding Corp.
EPA-compliant Recycling
DoD 5220.22-M Data Elimination
http://www.assetforwarding.com

 

[SteveW]

Hi Mike,

Fortunately for me, there was a very clear diagram on the side of the thing
to tell me how to set the jumpers!
Since replacing this one, I've now replaced another, older one, that already
had a SCSI ID of 5. The three pairs of jumper pins were described on the
label as ID0, ID1, and ID2. The SCSI ID of 5 had been achieved by connecting
ID0 and ID2.

This has reminded me of a sig I saw once. "there are only two groups of
people in the world - those who understand binary, and those who don't."
(I'm obviously in the latter group, I've no idea how ID0 and ID2 make 5!)
(Unless the ID0 makes 1, and the ID2 makes 4, and they add up!?)

Regards
Steve

 

[Rick]

Hi Mike,

Fortunately for me, there was a very clear diagram on the side of the thing
to tell me how to set the jumpers!
Since replacing this one, I've now replaced another, older one, that already
had a SCSI ID of 5. The three pairs of jumper pins were described on the
label as ID0, ID1, and ID2. The SCSI ID of 5 had been achieved by connecting
ID0 and ID2.

This has reminded me of a sig I saw once. "there are only two groups of
people in the world - those who understand binary, and those who don't."
(I'm obviously in the latter group, I've no idea how ID0 and ID2 make 5!)
(Unless the ID0 makes 1, and the ID2 makes 4, and they add up!?)

Exactly:

No pins set = ID0
Pin 0 set = ID1
Pin 1 set = ID2
Pins 0+1 set = ID3
Pin 2 set = ID4
Pins 0+2 set = ID5
Pins 1+2 set = ID6
Pins 0+1+2 set = ID7

Rick