On Saturday, 21 November 1998,
     MARIO SEMO wrote to IVAN TODOROSKI about Guess who's back... ;)

 IT>>   They both run at priority 0x200 (Regular, level 0) by default. So I
 IT>> type DIR /S (as an example of a CPU consuming process) in one window,

 MS> forget priority tests with commandprompts and dir commands. as i
 MS> remember IBM implemented special handling of cmd sessions sometime
 MS> (wth WARP3 or WARP4, cant remember). and do NOT try to use an add
 MS> on (PC or something) to change the priority. who knows what these
 MS> programs do.

  CMD sessions do not appear to have any special treatment over any
  other programs. Same things when I drag folder windows around. Could
  you elaborate on what you mean by this "special handling"?

  Also, Process Commander does NOT do "who knows what". The way it
  changes other process' priority is totaly documented and supported by
  the OS/2 API. It is a simple DosSetPriority() call. Don't see anything
  wrong with that, and haven't observed ANY side-effects whatsoever of
  using PC. And it actually does good, since it bailed me out of a LOT of
  PM hangs. Warp 4 with no FixPacks has quite unstable PM and WPS
  implementation.

 MS> write 2 applications, or write (as first test) 1 application with
 MS> 3 threads and then perform tests.

  Well you write it, and try this:

  Write one thread to run at priority 0x200, and the other at 0x201.
  Put this piece of code in the 0x201 one

   asm {
     x:
     jmp x
   }

  or something to that effect (I'll tell a great way to totally freeze
  your OS/2 system at the end of the message).

  Observe your first thread (one with 0x200 priority) totally stop
  (except for the starvation boost it will get every MAXWAIT seconds)!

 MS> and you will see everything is nice and good.

    Everything is NOT nice and good... the priority assignment of OS/2
    is a little dangerous, atleast on single-processor machines.


[Note: This bellow is totally unrelated to priorities or PM drawing]

    And here is a great way to TOTALLY and IRREVOCABLY freeze your OS/2
    system. Mouse will stop, and not even Ctrl-Alt-Del or
    Ctrl-Alt-NumLck-NumLck will work!

    Take any DOS assembler (even DEBUG will do) and create a simple
    program (.COM or .EXE, no matter) with this piece of code in it:

     cli
     x:
     jmp x

    Execute this in a DOS window.

    Hope you closed all the applications first... ;)

                                                            - Ivan -

.!. Oh bother, said Pooh, as he reached for the reset button.
--- Terminate 5.00/Pro [OS/2]
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