47 lines
1.8 KiB
Markdown
47 lines
1.8 KiB
Markdown
# 4600-project-1
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Project 1 for CSCE4600, for Team G4
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## Build
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Build with `make`
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Run with `make run`
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Clean with `make clean`
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## Explanation of Solution
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### Counting Semaphores:
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This project uses four counting semaphores:
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* `sem_freelist` tracks the number of blocks on the `freelist`.
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* This prevents any thread from trying to read a nonexistent (`nullptr`) block from the `freelist`.
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* `sem_freelist_minus_1` tracks the number of blocks on the `freelist` minus 1:
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* This is used to circumvent a deadlock situation where Thread-1 (the producer) will eat the last block on the `freelist` and put it on `list1`, where Thread-2 (the transformer) will never be able to consume it, since it's blocked on the empty `freelist`.
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* Without this, you'd need to check that `sem_freelist > 1`, and the project specifications only allow the use of P() and V(), A.K.A. `wait()` and `signal()`.
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* `sem_list1` tracks the number of blocks on `list1`.
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* This prevents any thread from trying to read a nonexistent (`nullptr`) block from `list1`.
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* `sem_list2` tracks the number of blocks on `list2`.
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* This prevents any thread from trying to read a nonexistent (`nullptr`) block from `list2`.
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All counting semaphores were used for thread synchronization.
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### Binary Semaphores:
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This project uses three binary semaphores:
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* `sem_freelist` guarantees mutual exclusion when accessing the `freelist`.
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* This prevents memory corruption, as list accesses are thread-unsafe.
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* `sem_list1` guarantees mutual exclusion when accessing `list1`.
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* This prevents memory corruption, as list accesses are thread-unsafe.
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* `sem_list2` guarantees mutual exclusion when accessing `list2`.
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* This prevents memory corruption, as list accesses are thread-unsafe.
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All binary semaphores were used for mutual exclusion. |