| Semaphores |
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| ä | Synchronization
tool (provided by the OS) |
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| that
do not require busy waiting |
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| ä | A
semaphore S is an integer variable that, |
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| apart
from initialization, can only be |
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| accessed
through 2 atomic
and mutually |
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| exclusive operations: |
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| ä | wait(S) |
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| ä | signal(S) |
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| ä | To
avoid busy waiting: when a process has |
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| to
wait, it will be put in a blocked queue of |
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| processes
waiting for the same event |
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