Monitor





Monitor may have one of the following meanings:

   * A computer display
   * A concurrent programming language construct which encapsulates
     variables, access procedures and initialisation code within an abstract
     data type. The monitor's variable may only be accessed via its access
     procedures and only one process may be actively accessing the monitor
     at any one time. The access procedures are critical sections. A monitor
     may have a queue of processes which are waiting to access it. Monitors
     in this sense were invented by C. A. R. Hoare.
   * A hardware device that measures electrical events such as pulses or
     voltage levels in a digital computer.
   * To oversee a program during execution. For example, the monitor
     function in the Unix C library enables profiling of a certain range of
     code addresses. A histogram is produced showing how often the program
     counter was found to be at each position and how often each profiled
     function was called.
   * A control program within the operating system that manages the
     allocation of system resources to active programs.
   * A machine code monitor used by programmers to modify computer memory
     contents and enter and modify assembly language programs.
   * A program that measures software performance.
   * USS Monitor, the ironclad warship of the American civil war.
   * A monitor warship type of ship based on the USS Monitor and built by
     several navies for coastal defence in the 1860s and 1870s.
     It reappeared in a different form during the First World War.
   * A large tropical lizard (family Varanidae); see monitor lizard