UNIX Configuration Guide:
PC-Based UNIX (SCO)

Configuration Switch Settings

Autoloader Switch Settings

Device Files for a PC-Based UNIX (SCO) System

For Intel Solaris Systems, use the instructions for Sun Solaris 2 systems.

Configuration Switch Settings

The configuration switches for an HP SureStore DAT drive installed on most PC-based UNIX systems (such as SCO UnixWare, Unix System/V, Open Server 5 or Open Desk Top) should be set as follows:

Note: The Media Recognition System can be disabled by setting switch 3 to ON but this is not recommended.

HP SureStore DAT24x6 and DAT40x6:
Autoloader Option Switch Settings

HP SureStore DAT external autoloaders have an additional selector switch on the rear panel. This switch sets different configurations for the autoloader mechanism and are read by the firmware at power-on. For a DEC system, this switch should be set to 7 (the default value), which sets the internal switches as follows:

Note: Set the value with the autoloader switched off.

The HP SureStore DAT24 internal autoloaders also have an option selector on the rear panel. These are four on-off switches that allow you to set the value, as above. Instructions for setting these switches are provided in the Installation Guide. You should not need to change them after installation.

For a more detailed explanation, please see Autoloader Option Switch.

Device Files for a PC-Based UNIX (SCO) System

To install the appropriate driver and device files on a SCO system, perform the following steps:

1. Run mkdev tape as root.
2. Select Configure SCSI tape drive
3. Select Install tape drive
4. Select the appropriate SCSI adapter.
5. Select the appropriate SCSI bus.
6. Select the Target ID to match the SCSI ID set on the back of the drive.
7. Set the LUN to 0.
8. Enter y to update the SCSI configuration.
9. Enter the following details (do not type the quotes):
   
   • "HP" for the Vendor identification string
   • "2" for the SCSI version to which the drive conforms
   • "2" for the Response Data Format (SCSI-2)
   • "4" for the DAT device

   Note:
   This procedure will automatically make the drive the default device, even if another device is already configured.

10. Enter "q" to leave the boot string displayed when the system is rebooted unchanged.
11. Enter "q" to return to the Main Menu.
12. Enter "q" to quit.
13. You are now prompted to rebuild the kernel and the kernel environment (which includes the device files). Perform both steps by answering 'y' when prompted, and select the new kernel to be booted by default.

You can use either of the following device files, as appropriate, for backup operations:

• /dev/nrStpY if you require a no-rewind device
• /dev/rStpY if you require a rewind device

Where Y is the instance number as assigned to the drive by the operating system (0 is the first device, 1 is the second, etc.).

Controlling Compression with SCO

Because SCO does not have any compression/no-compression device files, use tape setcomp to control the compression status of the drive as follows:

If you have multiple drives, you must specify the appropriate device files in the command. For example:

% tape -a 0 setcomp /dev/nrStp2

Use tape getcomp to tell you the current status of the drive.

Note: Do not use the SCO mt utility. This is obsolete and does not perform the same function as mt on other platforms. Use tape to achieve the same functionality.

Improving Performance Through Block Size on SCO

To improve performance on a SCO system, specify larger blocking factors for cpio and tar (use the b option of tar with an argument of 20 or use the B option of cpio). For example:

% tar cvbf 20 /dev/rStpY ./*

or

% find / -print | cpio -ocB > /dev/rStpY

or, if you have a version of SCO UNIX earlier than 5.x:

% find / -print | cpio -ocB > -O/dev/rStpY

Where Y is the instance number assigned to the drive by the operating system (where 0 is the first instance, 1 is the second, etc.).

Alternatively, you can use the tape command as follows:

% tape -a 32768 setblk <device file>

This explicitly sets the block size used for the drive when you are using built-in applications such as cpio and tar. The <device file> is either /dev/nrStpY or /dev/rStpY, as described above.