/dev/sdb8 looks about right. How did you get the information posted without knowing what partition to look at?
Some times the GUI is your friend. 
I can see the drive in Dolphin. I knew the approximate size and got the exact size in Dophin. Opening it in Dolphin confirmed it was root. Opening boot gave me the Boot directory. Of course that was only after trying to get the info using 'uname'. Did use 'uname -a' for the PATA drive.
The quick way to boot that partition is to copy the first stanza of your PATA installation and then paste it back directly under the first, so you have two identical stanzas. In the new second stanza edit it so that the root= line reads
root=/dev/sdb8 and the title reads
PCLOS - SATA.
Save the file and
reboot. At the boot menu, select the
PCLOS - SATA option then press the
Enter key. You should boot into the SATA installation, but you will be using the kernel and initrd from the PATA drive.
This may not work if there is too much difference between the contents of the two initrd images. If that is the case you will have to copy the initrd image from the SATA drive, and save it in the
PATA /boot directory with
-sata added to the full name, then change the
initrd line of the second menu.lst stanza again, to point to the
copied initrd image
by name.
Because the MB of the current computer is different from the original in which the SATA drive was in, even this may not work, in which case you would need to create an entirely new initrd image with the mkinitrd application, to get all the proper modules loaded. Obviously this is more involved, so for now try the first suggestion, and if it doesn't work, the second suggestion.
Post your results.
