Townshend Computer Tools DAT-Link - Page 32

28 Installation
that was in use. The hinv listing should now include a line such as:
Tape drive: unit 5 on SCSI controller 0: unknown
if the DAT-Link is prop erly connected. In this example, the DAT-Link was con-
nected at SCSI ID 5.
Conguring the Device Drivers
At this p ointyou need to create the IRIX raw tape devices in the /dev directory.
To do this, the sup eruser needs to change directory to /dev and run the command:
./MAKEDEV tps
Next, the superuser should create a device in the /dev directory called datlink0 .
It should be a link to the standard SGI tap e drive device with the appropriate SCSI
ID. Also, note that IRIX provides twotyp es of tap e devices, one whichswaps bytes
of each sixteen-bit word and one which do es not. The non-swapping device must
be used to access the DAT-Link .
If, for example, the DAT-Link is set for SCSI ID 5, on controller 0
8
, the device can
be created with the commands:
ln -s /dev/rmt/tps0d5ns /dev/datlink0
In the string, tps0d5ns , the 0 signies controller 0, the 5 signies SCSI ID 5, and
the ns indicates that the non-swapp ed device should b e used. Note that you will
need to be logged in as root to execute the above commands. You can now proceed
with the software installation in Section 2.6 b elow.
On IRIX, there is a program, mediad ,typically running which p eriodically p olls each
connected SCSI device to see if a removable media has b een changed. If mediad
polls the DAT-Link in this way, throughput will b e greatly reduced and SCSI errors
may o ccur. The solution is to disable mediad accesses to the DAT-Link device.
On IRIX 5.x and 6.2, this can b e accomplished by adding the following line to the
le, /etc/fsd.auto :
/dev/rmt/tps0d5nr /tape mediad rw,mon=off 0 0
On IRIX 6.3, add the following line to /etc/cong/mediad.cong , creating the
le if necessary:
ignore device /dev/rmt/tps0d5
8
The Indigo-2 and the O2 havetwo SCSI controllers.