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                     Copyright © 1996 Mark Russinovich

                       last updated December 9, 1996

 NTFrob V1.0 - Quantum Unit Selector

        Introduction   One of the most annoying characteristics of NT is
                       its lack of support for tuning various system
                       performance settings such as the foreground and
                       background process quanta (a quantum is the
                       time-slice, or length of time a thread will run
                       without being pulled off the CPU for another thread
                       to run). On NT Server, the quanta are fixed for both
                       foreground and background processes at 120ms, and on
                       NT Workstation a background process has a quantum of
                       20ms, and a foreground process has a quantum of
                       either 20, 40, or 60ms (the foreground boost slider
                       in the Performance tab of the System applet in the
                       Control Panel determines which).

                       Well, here's a little applet that will let you
                       "frob" (OSR terminology) the quanta to your liking.
                       The new quanta will immediately be applied to every
                       process in the system and will also affect new
                       processes that are created.

        Using NTFrob   NTFrob only works on NT 4.0 Final Release and SP1.
                       When you start NTFrob, it will display the system's
                       current foreground and background quanta. Simply
                       enter different values and press Apply. Press Reset
                       to restore the quanta to those that existed at the
                       startup of NTFrob. Note that values 0 and greater
                       than 420ms are effectively equal to a quantum of
                       10ms, and that NTFrob does not check against these
                       ranges.

        How it Works   NTFrob consists of a GUI that communicates with a
                       device driver to directly lookup and frob NT's
                       internal (and otherwise inaccessible) quantum
                       matrix. In addition, it travels the undocumented
                       list of processes and adjusts the quanta they are
                       assigned. When a thread starts a new quantum, it
                       inherits the quantum value from its process.
                       Similarly, when a new process is created, it adopts
                       the quantum setting of its parent.

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