Info:
Alpha Server ES40, True64 Unix 4.0F

Symptom:
root#file /dev/rrz*c
root#.
.
/dev/rrz24c: character special (8/49154) EIDE #3 CDR-8435 disk #192 (scsi ID #0) (SCSI LUN #0) offline
root#mount -r /dev/rz24c /mnt
root#/dev/rz24c on /mnt: I/O error

pls help me, i don't know if the hardware is bad.

I don't have access to a server with Tru64, but here are some things you might try:

1. Insure your cables are connected - double check them on each end (if this is a external cdrom)
2. At the console prompt (system powered up but halted) you should be able to enter the 'show device' command
>>> show device

Look that it shows all your devices (again, since it's been years for me on a Digital UNIX system, I don't know for sure if this will show the cdrom...you may have to check your documentation). If it does show the cdrom (along with all your hard disks), then at least this shows you have a connection from the system to the cdrom.

3. If this is a new device, you need to rebuild the kernel to support it. Documentation is on-line at Tru64 Compaq Version 4.0F

Hope this helps.

Thank you very much ,I will try.