Following up on mcleodnine's idea, I examined the slave drive's /etc/fstab file and discovered a problem.
While nothing was encrypted, there was one line I did not expect.
/dev/hda4 /home reiserfs defaults 1 2
I thought the slave drive partitions were: SWAP, /, /user, /opt
fstab revealed those partitions were: SWAP, /, /home, /opt
If /home (user files) did not exist on the root "/" partition, that would explain why /home was empty after mounting the slave's root, or "mount /dev/hdb1 /opt2"
Executing from machine #2 "mount /dev/hdb4 /home2" with machine #1's drive attached as a slave, properly revealed the user files from the slave, regardless of it's boot failure.
I finally recovered my user files. YaaaOsss My Friends, your contributions went to a good cause!
Note: Machine #1's Boot failure syntax
Early in the boot process, just after the file system mounted root, and before most devices were detected, this error occured.
Init: Entering runlevel 5
INIT: Id "1" respawning too fast: disabled for 5 minutes
INIT: Id "2" respawning too fast: disabled for 5 minutes
INIT: Id "3" respawning too fast: disabled for 5 minutes
INIT: Id "4" respawning too fast: disabled for 5 minutes
INIT: Id "5" respawning too fast: disabled for 5 minutes
INIT: Id "6" respawning too fast: disabled for 5 minutes
The above sequence looped every 5 minutes. Except for the POWER SWITCH, no "Hotkey(s)" or boot option interupted this inevitable error sequence.
My homework led me to believe Machine #1's boot failure may be fixable while mounted as a slave, by searching for error messages in its /var/log/messages, /var/log/news or /var/log/mail, and perhaps hours of experimental tweaking of its /etc/X11/XF86Config, or "/etc/inittab.
However, I believe, the amount of disk-drive jumper switching from slave to master required to manually test such tweaks, just to get it in runlevel 3, is beyond my threshold for pain.
Unlike Jeffrey below, the luxury of a Silo prompt or runlevel 3 eludes me and perhaps SuSE 8.0.
One clue found with www.google.com
Re: [suse-sparc] Netra problem with login
From: Jeffrey Young (firstname.lastname@example.org)
Date: Sun May 20 2001 - 16:52:19 PDT
Since, I now have the user data I need,
I now believe,
YaaaOsss My Friends, with God as my witness,
I will format that SOB
Thanks to all yall, for helping me recover my user files.
"..those who suffer for others do more damage to humanity than those who enjoy themselves." Carlo Petrini, founder of Slow Food