Refer to the instruction manual to install the card and the drives. For DPT, since a storage manager for Linux doesn't exist yet, you need to create a MS-DOS-formatted disk with the system on it (usually created using the command "format \s" at the MS-DOS prompt). You will also be using the DPT storage manager for MS-DOS, which you should probably make a copy of for safety.
Once the hardware is in place, boot using the DOS system disk. Replace the DOS disk with the storage manager. And invoke the storage manager using the command:
Wait a minute or so, and you'll get a nice menu of options. Configure the set of disks as a hardware RAID (single logical array). Choose "other" as the operating system.
The MS-DOS storage manager is a lot easier to use with a mouse, and so you might want to have a mouse driver on the initial system disk you create.
Technically, it should be possible to run the SCO storage manager under Linux, but it may be more trouble than its worth. It's probably more easier to run the MS-DOS storage manager under Linux.
You will need to configure the kernel with SCSI support and the appropriate low level driver. See the Kernel HOWTO for information on how to compile the kernel. Once you choose "yes" for SCSI support, in the low level drivers section, select the driver of your choice (EATA-DMA for most EATA-DMA compliant (DPT) cards, EATA-PIO for the very old PM2001 and PM2012A from DPT). Most drivers, including the EATA-DMA driver, should be available in recent kernel versions.
Once you have the kernel compiled, reboot, and if you've set up everything correctly, you should see the driver recognising the RAID as a single SCSI disk. If you use RAID-5, you will see the size of this disk to be 2/3 of the actual disk space available. The messages you see upon bootup should look something like this:
EATA (Extended Attachment) driver version: 2.59b developed in co-operation with DPT (c) 1993-96 Michael Neuffer, mike@i-Connect.Net Registered HBAs: HBA no. Boardtype Revis EATA Bus BaseIO IRQ DMA Ch ID Pr QS S/G IS scsi0 : PM2144UW v07L.Y 2.0c PCI 0xef90 11 BMST 1 7 N 64 252 Y scsi0 : EATA (Extended Attachment) HBA driver scsi : 1 host. Vendor: DPT Model: RAID-5 Rev: 07LY Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sda at scsi0, channel 0, id 8, lun 0 scsi0: queue depth for target 8 on channel 0 set to 64 scsi : detected 1 SCSI disk total. SCSI device sda: hdwr sector= 512 bytes. Sectors= 35591040 [17378 MB] [17.4 GB]
(The above display is for a setup with a single DPT SCSI controller, configured as RAID-5, with three disks of 9 GB each.)