Trace string *=all=disabled

Hi,
In the server perspective of WSAD there is a "Trace" tab. It has an "Enable Trace" checkbox and a field called "Trace string" that contains "*=all=disabled".
What is this? What does "*=all=disabled" mean?
Thanks.

see section 18.4.1 Diagnostic Trace Service of redbook sg246195

Thanks for the response, but the link didn't explain trace strings.
This is a question on IBM's 286 sample test:
Which of the following are valid trace strings for WebSphere Application Server?
A. com.ibm.ws.*=all=enabled
B. *=startStop=true
C. entryExit=full=enabled
D. *=debug=enabled
E. com.ibm.ws.classloader.JarClassLoader=event=true
F. com.ibm.ws.runtime.* = error = enabled
I can't find information about what these strings mean and what their format should be. If "tracing is most likely to be used by IBM Service for diagnosing WebSphere problems and not by the typical user diagnosing application problems", as your link suggests, I wonder why IBM puts this question on the exam. But since the question IS on the exam, I would like to understand it. Anybody?

RTFM
Trace string specification
Trace strings must conform to a specific grammar for processing by the trace
service:
COMPONENT_TRACE_STRING[:COMPONENT_TRACE_STRING]*
For example:
COMPONENT_TRACE_STRING = COMPONENT_NAME=LEVEL=STATE[,LEVEL=STATE]*
Where:
COMPONENT_NAME is the name of a component or group registered with the
trace service. Typically, WebSphere Application Server components register
using a fully qualified Java class name, for example
com.ibm.servlet.engine.ServletEngine. In addition, you can use a wildcard
character of asterisk (*) to terminate a component name and indicate multiple
classes or packages. For example, use a component name of
com.ibm.servlet.* to specify all components whose names begin with
com.ibm.servlet.
LEVEL = all | entryExit | debug | event
Level is the type of tracing to perform. You can specify more than one type by
separating them with commas.
STATE = enabled | disabled
Examples of legal trace strings include:
com.ibm.ejs.ras.ManagerAdmin=debug=enabled
com.ibm.ejs.ras.ManagerAdmin=all=enabled,event=disabled
com.ibm.ejs.ras.*=all=enabled
com.ibm.ejs.ras.*=all=enabled:com.ibm.ws.ras=debug=enabled,entryexit=enabled
Trace strings cannot contain blanks and are processed from left to right.
Specifying a trace string like:
abc.*=all=enabled,event=disabled
Enables the trace for all components whose names start with abc, then disables
event tracing for those same components. This means that the trace string
abc.*=all=enabled,event=disabled is equivalent to
abc.*=debug=enabled,entryexit=enabled.
...

Rufus,
My browser was having trouble displaying that RedBook in HTML mode. When I looked at the book later as a PDF file, I was able to see it nicely.
That is exactly what I needed to know. Thanks a lot for the help!