Creating Customized Device Special Files for Tape Devices

The default device special files created by insf handle most routine tape-drive requirements. For special circumstances, however, you can use SAM or the tape driver options of the mksf command to create device special files. For complete syntax information, consult the SAM online help or mksf(1M) manpage in the HP-UX Reference.

Examples

In each example, the tape device is at card instance 1 for the ext_bus class of interface card to which the tape device is attached, as shown by /usr/sbin/ioscan -fn output.

Reading a Tape on a Different Format Device

Typically, a tape written on a Wangtek QIC 1000 device cannot be read on a Wangtek QIC 525 device. This is because the default device special file /dev/rmt/c#t#d#BEST will write in QIC 1000 format.

To create the device file needed for writing QIC 525 format, use the following command. Also shown are the resulting device special files.

/usr/sbin/mksf -C tape -I 1 -b QIC_525 

/dev/rmt/c#t#d#QIC525          on a system allowing long file names, or
/dev/rmt/c#t#d#f5                 on a system requiring short file names




	NOTE: In short file name notation, `f#` (or `i#`, shown in next example) denotes device-dependent values. See mt(7) in the HP-UX Reference for explanation.

Allowing for Trial and Error

If you are attempting to use a new tape device with the stape driver and you do not know exactly how to configure it, you can use the -e option to create a device file that will let the driver try several configurations to find one that will work.

The following shows the command line and resulting device special files:

/usr/sbin/mksf -C tape -I 1 -e 

/dev/rmt/c#t#d#eBEST		          	on a system allowing long file names, or
/dev/rmt/c#t#d#i#                on a system requiring short file names

Avoiding Data Compression

Sometimes an operation requires use of a device special file that writes data without compression. For example,

On HP-UX, the STK 3480 tape drive requires that if data cannot be compressed to fewer than 102,400 bytes, it must be written to tape without compression.
A tape created on an HP35480A will have been written with data compression enabled. To read the tape on an HP35470A tape drive, you must use a device special file that does not compress data.

To accomplish this, you cannot use the default BEST density because it will automatically compress the data.

To create device special files for the STK 3480 that write data in uncompressed form, use the following sample command. Also shown are the resulting device special files.

/usr/sbin/mksf -C tape -I 1 -b D3480 

/dev/rmt/c#t#d#D3480         on a system allowing long file names, or
/dev/rmt/c#t#d#f1               on a system requiring short file names

To create device special files for the HP35480A to write a tape in uncompressed form, use the following sample command. Also shown are the resulting device special files.

/usr/sbin/mksf -I 8 -C tape -b DDS1 


/dev/rmt/c#t#d#DDS1          
on a system allowing long file names, or
/dev/rmt/c#t#d#f1               
on a system requiring short file names

This tape can now be read on a tape drive, regardless of whether or not it supports data compression.

Creating Customized Device Special Files for Tape Devices

Technical documentation

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Examples

Reading a Tape on a Different Format Device

Allowing for Trial and Error

Avoiding Data Compression