Hello UNIX-community,
We have an older SCO UNIX-system running PCS3 (an industrial platform) and since a few weeks we are experiencing problems with our archiving software.
For about ten years, the system archives data to Magneto-Optical discs (MO-discs) and thus far it has worked fine. Recently the archiving routine produces errors and the backup fails. We have changed the hardware (MO-disc, MO-drive and SCSI-card) to no avail.
We still suspect the MO-drive(s) and so we want to remove them from the equation. Instead we want to attach an external SCSI-harddrive to the system and put the data there.
Problem is that we cannot change the executable that performs the backup. Only thing we know is that it writes to "archive0", which is somehow connected to the MO-drive (rmo0).
Is it possible to link "archive0" to an external HDD and could anyone explain the necessary modifications (including the onces needed for mounting the external HDD)?
Thanks in advance. Any help is appreciated 
Maybe you can get along with these two articles, pointing to create devices with mknod (2nd talks about SCO).
Understanding Unix Devices
Understanding SCO Unix Device Drivers
If you are successful in replacing the MO behind archive0 with a disk, don't forget to be able to reverse this so you can restore old archives from MO again, if needed.
Hello zaxxon,
Thanks for your reply. The links you provide contain a lot of material, so I'll have to study it.
If I don't understand some of it or if I can't get things to work, I'll be back 
(hopefully I do get things to work, then I will be back too, to report it )
Hello zaxxon,
I have successfully added my external SCSI-harddrive to the system (mkdev hd) and am able to mount the filesystem(s).
Re-routing archive0 to the harddisk also seems to succeed, but I can't really test that: apparently the archiving-software uses ioctl functions to check the state of the drive and the harddisk obviously reacts different than the MO-drive 
So your help was indeed helpful, but my problem is not yet solved. Now I will have to find a way to workaround the archiving-software.
Thanks anyway:b: