problem of boot/reboot from SimpleTech SP-U25/60 USB drive on PCG-6J2L

[Jin Guojun [VFFS]]

This is my first time to install FreeBSD 5.x/6.x on a USB drive, so I am 
not sure
if the boot/reboot problem is particular to this drive (SimpleTech 
SP-U25/60), or
it is a generic USB issue (I do not have a second USB drive to confirm 
the problem).

This USB device contains a WDC WD60 0VE-07HDT0 0811 drive.

System 1 -- desktop

    ECS 848P-A7 motherboard with 2GB DDR and Intel P4 506+ CPU
    ASUS Symbios 875 SCSI controller

 issues:
    (1a) attach some SEAGATE ST39102LW on SCSI controller, system boot OK,
    (1b) if a Toshiba XM-6201B CD drive or some old SCSI drives 
attached, BIOS
             can still detect this USB drive, but it is not bootable. It 
looks like hardware issue.

    (2) After system successfully boot up, reboot/shutdown [-h, -p] will 
hang the system
       after following message:

       No buffer busy after final sync
       Uptime:   2m11s

    Only way to get system reboot or shutdown is to power cycle the machine.


System 2 -- laptop

   
          Sony VAIO PCG-6J2L

    Problem:    installing FreeBSD 5.x/6.x on USB drive has no problem.
                      system cannot boot (hangs system) regardless the 
FreeBSD install on
                     this laptop or from other computer.
                      system will not respond to soft-reset or any key 
stroke once hangs. Power
                      down the system is the only way to go.
 
                      Boot fails immediately once anything starting show 
on the screen. It looks like
                    some type of error message repeatedly spiting on the 
screen. It scrolls too fast
                     to read. It seems something like:

                      int=###### ######  
........................................................................
                      ext=###### ###### 
........................................................................

    Is this a generic USB drive issue or particular problem for this USB 
drive with this VAIO
    machine?
    Is there a workaround to make a USB drive (or this USB drive) to 
boot from this VAIO laptop?

    I need to boot this laptop from an external drive.
    Please let me know how can I boot an external drive (any type 
external drive) on this Snoy
    VAIO PCG-6J2L laptop.

TIA

    -Jin