xy: cannot exec first read

[Brent Chapman]

# 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.

We ran into this in late December and early January.  This is indeed a bug
in the 2.7 (and 2.8, from what I'm told by Sun) PROMs.  We had a 3/280
that started exhibiting the same problems after a motherboard swap during
maintenance, and we finally narrowed it down to the new PROMs.  Going back
to an older boot PROM (2.6 or earlier) fixed the problem.  I don't know if
it's been fixed in subsequent versions of the PROM (I've seen at least one
machine with PROM rev 2.8.3, though).

While we were tracking this down, we heard from several other people at
other sites with the same problem, and folks from Sun were working on it.
The person at Sun who we working with and who seemed to be the one
tracking the problem was Mike Persichetty <mike at sun.com>.  Sorry, I don't
have a bug number (do such things exist for hardware problems?) or service
order number handy, but hopefully he'll remember it. 


-Brent
--
Brent Chapman					Capital Market Technology, Inc.
Computer Operations Manager			1995 University Ave., Suite 390
brent at capmkt.com				Berkeley, CA  94704
{apple,lll-tis,uunet}!capmkt!brent		Phone:  415/540-6400