GPSS Simulator Specification

Introduction to GPSS

GPSS (General Purpose Simulation System) has been developed over many years, principally by IBM.

The system to be simulated in GPSS is described as a block diagram in which the blocks represent the activities, and the lines joining the blocks indicate the sequence in which the activities can be executed. Where there's a choice of activities, more than one line leaves a block and the condition for the choice is stated at the block.

GPSS focuses in the life-cycle of a transaction.

For detail, go to here http://www.cs.mcgill.ca/~hv/classes/MS/GPSSH/

GPSS Simulator Requirement

Use python to interpret pseudo GPSS file and generate simulation result

Simulator should support the following blocks

GENERATE(Mean, Modifier, count)	Create Transactions whose interval is Mean+-Modifier until #transactions = count
SEIZE(Facility No)	Allows the transaction to engage a facility if it's available
RELEASE(Facility No)	Allows the transaction to disengage the facility
ADVANCE(Mean, Modifier)	The transaction remain in the advance block for interval = Mean+-Modifier
TRANSFER(Select Factor, Block A, Block B)	The probability of going to block A is 1-S, and to block B is s. BOTH is not supported.
TERMINATE	Remove Transaction
START	Set termination number

Simulation result should include

Total simulation time	The time from beginning to end of simulation
Average simulation time	Total simulation time/#transactions
Average utility of facility	Average utility of an facility
Average occupied time of facility	Average occupied time of facility
The entry number of block label	Shows how many transactions go into the block label
Tracing result	Display transactions go through all blocks to ease the burden of debugging if VERBOSE flag is turned on

GPSS simulator kernal

For detail, please see http://isgwww.cs.uni-magdeburg.de/~pelo/s1e/sa5/sa52.shtml