Simulation Toolboxes

• QUEUE - linked-list objects (pc-ASCII file)
• Simulation using Processes
• Message passing by Processes
• Synchronization using Resources
• Animating Simulations

• CLOCK object - needed by all simulations.
• QUEUE: General lists: fifo, stack, ordered You declare type of list elements, and virtual methods to determine ordering and equality.
• SIMOBJ: Simulation objects - when initialized, they link themselves into a list. After that, global reset and report can be done. - used by all the other units.
• MCOBJ: Monte Carlo objects - Random number generators
• STATOBJ: Statistical instrumentation ..as objects
• QNETOBJ: Queueing network scenarios Sources, sinks, transactions, and servers Servers can now be "Unavailable" with corresponding statistics.
• DIS_EV: Discrete event systems - event-based library. An event list, ordered by time, is maintained, and a monitor calls the appropriate event procedures. (this unit uses some type declarations in QNET.)
• COPROC: Co-procedures Context switching between "processes" - some tricky assembly language code, each process has it's own life cycle implemented as a procedure, and this code switches control and stacks between them.
• PROC_MAN: Process manager Allows processes to suspend themselves, go to sleep, wait in (semaphore) queues, and go to sleep (ultimately causing the clock to advance).
• MESSAGE: Synchronization by Message passing, a higher level built upon semaphores, allows processes to communicate with one another.
• RESOURCE: Synchronization by resource acquisition. Waiting for the resource (a server) is implicit, using a semaphore queue. A resource can also be made unavailable.
• ANIMATOR: Animating simulations. Provides animator object, which maintains a list of AnimationObj's and displays them on the screen at regular (real) time slices. In particular, a queue is shown as a variable length bar.

USES heirachy:

                 SIMOBJ    QUEUE   CLOCK
                     \      |      /
        QNETOBJ ------ COPROC ---- STATOBJ ---- MCOBJ
                            |      |
                            PROC_MAN
                          /    |     \
                   MESSAGE  RESOURCE  ANIMATOR

all the toolboxes assume a global variable TheClock, declared as one of the types in CLOCK.

Ordering of units: SIMOBJ must appear in the USES statement before PROC_MAN, because the Reporter global object must be initialized before Monitor.

Main program examples:

• Love cycles of Gont - a continuous simulation
• Manuel's love potion shop - an event-oriented discrete-event simulation
• The dining philosophers - If they all pick up a fork at once, deadlock results, and they all starve!
• Test of process-oriented units COROU & PROC_MAN. Three professors play a game of "hot potato" until the monitor counts to 25.
• Manuel's love potion shop using the process toolbox - "process oriented"
• Manuel's shop using Message passing
• Manuel's shop using Resources. Also lost customers and Unavailable servers.
• Stable marriages The marriage tournament of Morven, being Kreutzer's Simula example, rewritten in Pascal using our processes. Message ports are used to pass love notes.
• Ferry boat crossing. Master-Slave synchronization using messages.

Please note:

• The file COPROC.PAS is incompatible with Turbo Pascal 6.0, the proper version for it is named coproc.v60

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