Setting the IBM_trace level for static tracing

The user can still enable or disable static IBMtape tracing and set the IBM® trace level in /etc/system or run the adb system command. The host is required to reboot to enable or disable the tracing when the trace level is set in /etc/system. The IBMtape driver must be loaded in the kernel. If the tracing is enabled or disabled by using the adb command, the tracing starts or stops at the next device open.

The default value for IBM_trace is zero (0). You can define another IBM_trace value by placing an entry in /etc/system so that IBM_trace is set at each restart. For example, this entry in /etc/system sets IBM_trace to 2 at each restart.
set IBMtape:IBM_trace = 2

When IBM_trace is set in /etc/system, it affects tracing during driver loading, initialization, and operation.

You can also set or modify the IBM_trace value manually in an adb session. Because the driver must already be loaded and initialized before this method is used, the trace value that is set is active only during driver operation.

In this sample session, ksh> is a shell prompt, and adb> is the adb session prompt. Commands that you enter are in boldface. Explanatory comments follow number signs (#) or exclamation and number sign pairs (!#). Text lines without a prefix are adb session responses to commands.
#  Start adb session and set session prompt.
ksh> adb -P "adb> " -k -w /dev/ksyms /dev/mem
physmem 7c5e
!#  Set default for input values to base 10.
adb> a$d
radix=10 base ten
!#  Display current IBM_tape value as unsigned decimal integer.
adb> IBM_trace/u
IBM_trace:      0
!#  Set new IBM_trace value.
!#  adb will confirm the old and new values.
adb> IBM_trace/w 2
IBM_trace:      0       =       2
!#  Quit session.
adb> $q
#  Back to the shell.