DOSDBG - A DOSEMU tool for dynamic control of debug information

This tool is intended as an aid for developers of DOSEMU.  From within the
DOS session, you may query the current state of the debug output flags.  Also
the flags may be modified so that different debug information is output
to the debug file for DOSEMU.  The main reason to use this program would
be to restrict the debug file from growing too big, and getting filled with
impertinent (and possibly distracting) debug output.

For example, if you are debugging port I/O, you can start DOSEMU with the
debug flag for port I/O turned off.  Then, inside the DOSEMU session, right
before you run some test which you are interested in, you can run

	DOSDBG +i
	
to turn on port I/O debug messages on.  After your test is complete, run

	DOSDBG -i
	
to turn on port I/O debug messages off.  If you subsequently look at the
debug output file, it will only have port I/O debug messages for the brief
period when you had the flag turned on.

To see help for DOSDBG, just type "DOSDBG help" at the DOS prompt.  You will
get the following screen of help information.

============================================================================

Usage: DOSDBG [string|HELP]
If no string is specified, then DOSDBG will show the current debug settings.
  If HELP is specified, then this screen is displayed.  Otherwise <string>
  is parsed and used to change the current debug settings.

<string> can contain letters, and the '+' and '-' characters.
  Letters denote message classes from the following list:

k  keyboard     d  disk         R  disk Reads   W  disk Writes
h  hardware     i  port I/O     v  video        w  warnings
s  serial       m  mouse        p  printer      g  general
x  XMS          E  EMS          I  IPC          c  configuration
n  network
a  all (shorthand for all of the above)

Any classes following a '+', up until the end of string or a '-',
  will be turned on.  Likewise, any classes following a '-', to the
  end of string or a '+' will be turned off.

The character 'a' acts like a string of all possible debugging classes,
  so "-a" turns all message off, and "+a-RW" would turn all messages
  on except for disk Read and Write messages.

============================================================================

I hope someone finds this useful.  Comments are encouraged.

Tim Bird
(tbird@novell.com)