Backup to /dev/st0 works, but not to /dev/nrst0

[Jarmo Paavilainen]

Hi,

I want to be able to do incremential backups, and I thought that I use tar to do them.

"tar cvf /dev/st0 /home"

works fine, but it does not fill the tape.

So I thought that I make several backups to the same tape.

"tar cvf /dev/nrst0 /home"

Does not give me any errors, but it failes.

"mt /dev/nrst0 'almost anything'" gives me an ioctl error.

but "mt /dev/st0 'almost everything'" works fine (except reten?)

Why does the "non rewinding" device fail?

System is:
    Seagate DAT-3 SCSI
    RedHat 5.2

// Skorpio