CIS 552 Advanced Unix Programming

Professor Spiegel

Kutztown University

Topics:

ConcurrencyUnix Internals

•pipe, fork, exec, wait, signals, etc;Interprocess Communication

•Shared Memory, Semaphores, Message Queues?Threads? (maybe)Process Coordination

•Critical Sections

Deadlock

Here’s where we start

Time – used to order events

Event – A (potentially) sensed change

Process – An executing program

Is a program an executing process?

No. A program can, when executed, cause the occurrence of multiple processes

A Couple of Definitions

Concurrent – adj. acting in conjunction; agreeing; taking place at the same time; accompanying; n. a joint or contributory cause

Concurrently – adv. to run together

Parallel – adv. continuously at equal distance apart; precisely corresponding; similar; n. a line equidistant from another at all points; a thing exactly like another

n. union; concurrence of events

Precedence GraphsDirected Edge – Arrow from one node to another

e.g. A BAssume A & B are processesA occurs before (precedes) B,OR, B occurs after (follows) A

A B C D Sequential

A

B

C

D

Facts:• A precedes B• A precedes C• A precedes D• B precedes D• C precedes D

Question: What is B’s relationship to C?

Compiling & DebuggingRun gdb under emacs to debug your programs

Manual is available at URL:http://faculty.kutztown.edu/spiegel/Debugging/DebugPrimer.htmYou must also be able to write makefiles on your own

Manual is available at URL:

http://faculty.kutztown.edu/spiegel/Makefile/Makefile.htmThere is a link to each of these on my faculty

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