Specifications

The following examples show why the restriction on appending
data exists and how to successfully append data.
First, suppose you have a tape loaded in an Archive SCSI tape
drive. You choose to write a number of files on your tape drive
using the tar(C) and tape(C) commands on a no-rewind tape
device, /dev/nrStp0. You enter the following series of commands:
tape -s rewind /dev/nrStp0
tar cbf 20 /dev/nrStp0 first batch of files
tar cbf 20 /dev/nrStp0 second batch of files
tape -s rewind /dev/nrStp0
tar tvf /dev/nrStp0
tar tvf /dev/nrStp0
After checking the integrity of the first two batches of files with tar
tvf /dev/nrStp0, you decide to write the third batch of files. You
execute the following command:
tar cbf 20 /dev/nrStp0 third batch of files
If you have the UNIX SCSI Manager installed, the SCSI tape driver
reports the following error:
Warning: Stp
: Possible
SCSI Error:
Warning: Illegal Request:
This error occurs because you forgot to pass through the GENERAL
state to go from the READ to WRITE state.
To successfully append the third batch of files, you must issue a
tar t or tape rfm command to cause a read error. The read error
allows you to enter the GENERAL state before entering the WRITE
state.
If you see the previous error message, you can execute the
following tar commands on the no-rewind device as follows:
tar tvf /dev/nrStp0 (creates an read error. but
no error message)
tar cbf 20 /dev/nrStp0 third batch of files
Installing Software Drivers for UNIX
7-13