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semaphores

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Join Date: Apr 2008

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cppsevennine cppsevennine is offline

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semaphores

Apr 9th, 2008

was hoping someone could help me with semaphores...im a little confused

heres the question:

There are three kinds of processes in a system: type A, type B and type C. There are
many processes of types A and B, but only one process of type C. The type C process
cannot begin its task (Task_C()) until n processes of type A or m processes of type B
finish their respective tasks. More specifically, the type C process must block itself until
enough processes of type A or type B complete their tasks. Write synchronization code
for the three types of processes using semaphores. Use the templates below for each
process type. Hint: You’ll also want to use integer counts.

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Join Date: Nov 2004

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jwenting

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duckman

Re: semaphores

Apr 9th, 2008

crosspost

As people are clearly allowed to attack me but I'm not allowed to defend myself, I no longer post to this site.

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Join Date: Oct 2007

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jaux

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Re: semaphores

Apr 15th, 2008

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
a = b = 0 # shared counters
sem(0)    # semaphore initialized to 0
 
func_A:   # code for type A process
    a = a + 1
    sem.V
 
func_B:   # code for type B process
    b = b + 1
    sem.V
 
func_C:   # code for type C process
    while (a < n && b < m):
        sem.P
    # critical section
a = b = 0 # shared counters
sem(0)    # semaphore initialized to 0

func_A:   # code for type A process
    a = a + 1
    sem.V

func_B:   # code for type B process
    b = b + 1
    sem.V

func_C:   # code for type C process
    while (a < n && b < m):
        sem.P
    # critical section

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