First of all, as usual thanx a LOT to everybody who responded...you know who
you are (I hope ;-)
Anyway, it turned out to be a  hardware-problem, but a lot of interessting
stuff was suggested:
1. Run this program when the tape is rewinded - it'll tell you if the drive
is accessable:
# include <stdio.h>
# include <unistd.h>
# include <fcntl.h>
# include <string.h>
main()
{
        int fd;
        char data[256]=  "<fill data here>";
        fd = open ("/dev/tape/tape0_d1", O_RDWR);
        if (fd == -1)
        {
                printf ("%s", strerror (errno));
                // Here you may come to know why open fails
                exit(0);
        }
        if (write (fd, data,strlen (data)) == -1)
        {
                printf ("%s", strerror (errno));
                // Here you may come to know why write fails
                exit(0);
        }	
}
2. Remember to use mt status, vdump with the -D option, trying with other
tools like tar, cpio etc., reseting the SCSI-bus with drivepower off/on, or
try to use the drive with the SCU-utility.
<Med venlig hilsen>
Danny Petterson	Dimension Danmark A/S
System Konsulent	danny.petterson_at_dmsn.dk
Mobil: +45 29486827	Hovednummer: +45 87933600
</Med venlig hilsen>
>  -----Oprindelig meddelelse-----
> Fra: 	Danny Petterson  
> Sendt:	10. april 2002 11:35
> Til:	tru64-unix-managers_at_ornl.gov
> Emne:	Tru64 5.1/AIT-tape problem
> 
> Hi Managers!
> This is with out a doubt an easy one......my AIT-drive has stopped
> working.....an example:
> #mt offline 
> #mt online 
> #mt rewind 
> # vdump 0u /usr
> vdump: can't open dev </dev/tape/tape0_d1>; [13] Permission denied
> Whats wrong here?
> 
> 
> 
> 
> 
> <Med venlig hilsen>
> 
> Danny Petterson	Dimension A/S
> System Konsulent	danny.petterson_at_dmsn.dk
> Mobil: +45 29486827	Hovednummer: +45 87933600
> 
> </Med venlig hilsen>
> 
> 
Received on Tue Apr 23 2002 - 12:48:30 NZST