xy: cannot exec first read

[Joseph Moran]

Our system some times fails to boot and prints out:  "xy: cannot exec
first read" and returns to the monitor prompt.  After this happens, typing
"b" to the monitor sometimes will reboot the system.  However, other
times, this error is persistent and you continue getting the same "xy:
cannot exec first read" message from the monitor each time you try and
boot from the disk.  In these cases, powering cycling the CPU doesn't
clear the error condition.  The only way to recover from this condition is
to power cycle the *disks*.  From this I conclude that the disks are
sometimes left in some funny state during a clean shutdown that the boot
PROM may not be able to clear during its reboot sequence.

We have a Sun-3/160 with PROM revision level 2.7 and a Xylogics 451
controller connected to 2 850 Mb CDC Saber drives.  Our support people
have replaced the 451 controller, but the problem did not go away.  This
seems to leave the disk, the cabling, or the boot PROM as the most likely
suspects.  I would prefer not to change the disks unless I have more
evidence that this could really be the problem.

Does anyone know what types of things can cause this error message?  Does
anyone with monitor sources know what is happening when the monitor prints
the "xy: cannot exec first read" diagnostic?  Has anyone else out there
seen this problem?


Joseph Moran
Legato Systems, Inc.
260 Sheridan Avenue
Palo Alto, CA  94306
(415) 329-7886
mojo at Legato.COM or {sun,uunet}!legato!mojo