I had exactly the same symptoms, which turned out to be hardware.
In my case I prised the thing apart, cleaned up the sensitive bits and
put it together. No problems since. Best verification would be to swap
with another unit if available.

There was nothing logged that I could see regarding the fault - as you
say, it just disappeared according to the software.

Les.

terry433iid@yahoo.com wrote:
> I have an Ultra60 running Solaris 9 and the cdrom does not seem to be
> working...I place a CDROM in he drive and am unable to see /cdrom. I
> have ran volcheck to try and have the volume manager recognise this
> device but to no avail. Any ideas how I can debug if the device is
> broken or just simply not getting picked up by solaris?
>