scsi bus and tape backup questions

[Bill <bill@gpfn.sk.ca>]

greetings all:

i have a couple of questions i hope someone can answer for me.

to start:  i have a sparc station and linux (debian 2.1, 2.0.35 kernel)

1st question - re: scsi

my system works pretty good.  i am only curious as to why the sparc
scsi bus locates the internal system hard drive as target 3 when i have
external hard drives, as it is physically closer to the system.  i.e.

esp0: FAST chip is fas100a (family=0, version=2)
ESP: Total of 1 ESP hosts found, 1 actually in use.
scsi0 : Sparc ESP100A-FAST
scsi : 1 host.
  Vendor: SEAGATE   Model: ST15230N          Rev: 0638
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sda at scsi0, channel 0, id 0, lun 0

  Vendor: SEAGATE   Model: ST15230N          Rev: 0638
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sdb at scsi0, channel 0, id 2, lun 0

  Vendor: SEAGATE   Model: ST1480   SUN0424  Rev: 8628
  Type:   Direct-Access                      ANSI SCSI revision: 02
Detected scsi disk sdc at scsi0, channel 0, id 3, lun 0

  Vendor: HP        Model: C1533A            Rev: 9503
  Type:   Sequential-Access                  ANSI SCSI revision: 02
scsi : detected 3 SCSI disks total.

sda and sdb are in an external box (scsi id 2) whereas the small
internal is sdc.  i am just curious why the sparc does not find and
id the internal first, i.e.  target 0 or 1; sda.  ???


2nd question:  re: tape backups.

i am trying to finess mt, dump, and restore to do the job for us.  
they work o.k., except that there are a few main information bits
that seem to be missing.  i went through the mans on each of 
these, and i can't see anywhere an operation that will tell me how
much space is left on the tape.

GNU mt version 2.4.2

Package: dump
Version: 0.4b4-13


3rd question:  cdrom drive:

i also have a cdrom drive ii want to put on the system.  whenever i
add it to the chain, however, i get a scsi bus interrupt; reset infinite
loop when i try to boot.

here's how my system looks

as above for the hard drives.  external case with hard drives: id 2

plus:  hp tape backup: scsi id 4

this configuration works fine.   but when i add the cdrom to the end
of the chain, i have the problem.  the last device is terminated
properly.

with respect to scsi types;

sparc - (fast scsi 2)   --> external drives (scsi)  --> hp tape (scsi)
  --> cdrom (sun - fast scsi 2) 

i tried setting the cdrom as device 5 and 6, neither worked. 

however, the nvram probe-scsi util did find them all properly and
it looked fine in that setting.  it was only when i went to boot when
it went into an infinite loop.

could it be a driver problem?   i have the sg and st modules loaded.


thanks for any assistance with this.


bill