[rhn-users] sg driver question

[Kenneth Sarno]

I installed the sg driver into my RHEL 4 2.6.9-22.0.2.ELsmp kernel 
running on an Athlon 64 X2 4200. I installed it because I bought some 
generic Unix tape backup software that uses it.

I have an Adaptec 29320 SCSI controller, which is a PCI-X SCSI host 
adapter that's nonetheless stuck into an old-style PCI slot (my 
motherboard doesn't have PCI-X). It seems to work fine with 
everything but the sg driver. Everything is terminated properly etc.

When I use mt -f /dev/tape[01], the mt program issues commands to my 
two tape drives (a Quantum DLT VS160 and an IBM Ultrium LTO 3) 
through the st device interface with no problem.

When I do an sg-scan -i, my two tape drives are shown as /dev/sg4 and 
/dev/sg5 (SATA disks show up too with lower sg device numbers). The 
tape drives appear to be listed in the right place on the right bus.

However, "mt -f /dev/sg[45] eject", or any other mt command for that 
matter, returns an error message "command not permitted". As far as I 
can tell, no program other than sgscan can see the tape devices, 
including sg-dd, regular dd, tar, etc. Tar hangs when I try to read 
an sg tape device.

There does not seem to be any other disruption to the system caused 
by the simultaneous presence of st and sg.

I'm pretty stumped. Any help would be appreciated.

Thanks.

--Ken S.