Simulation and modeling - Old Questions

GPSS (General Purpose Simulation System) is a highly structured and special purpose simulation language based on process interaction approach and oriented toward queuing systems.
- The system being simulated is described by the block diagram using various GPSS blocks.
- Each block represents events, delays or other actions that affect the transaction flow.
- GPSS model is developed by converting the block diagram into block statements and adding the control statements.

Any four Program control statements that are used in GPSS are:

1. CLEAR: A CLEAR Command returns the simulation to the unused state.

        CLEAR A

    Operand:

        A - ON or OFF. If the A Operand is omitted, ON is assumed. Optional. The operand must be ON, OFF or Null.

2. END: The END Control Statement has been replaced by EXIT, which can terminate a Session. END is now a keyword in the PLUS Language.

3. RESET: A RESET Command marks the beginning of a measurement period.

            RESET

    Operands:  None.

4. START: A START Command begins a simulation.

        START A,B,C,D

    Operands:

        A - Termination count. Required. The operand must be PosInteger.

        B - Printout operand. NP for “no printout”. Default is to print a standard report. Optional. The operand must be NP or Null.

        C - Not used. Kept for compatibility with older dialects of GPSS.

        D - Chain printout. 1 to include the CEC and FEC in the standard report. Optional. The operand must be Null, or PosInteger.