From 466f63539217c2a4c9b4e57ecd993db097161dcb Mon Sep 17 00:00:00 2001
From: John Breaux <JohnBreaux@my.unt.edu>
Date: Wed, 6 Apr 2022 00:20:36 -0500
Subject: [PATCH] Update README.md

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 README.md | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

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 # 4600-project-1
 
-Project 1 for CSCE4600
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+Project 1 for CSCE4600, for Team G4
+
+## Build
+
+Build with `make`
+
+Run with `make run`
+
+Clean with `make clean`
+
+## Explanation of Solution
+
+### Counting Semaphores:
+
+This project uses four counting semaphores:
+
+* `sem_freelist` tracks the number of blocks on the `freelist`.
+   * This prevents any thread from trying to read a nonexistent (`nullptr`) block from the `freelist`.
+
+* `sem_freelist_minus_1` tracks the number of blocks on the `freelist` minus 1:
+  * 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`.
+  * 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()`.
+
+* `sem_list1` tracks the number of blocks on `list1`.
+   * This prevents any thread from trying to read a nonexistent (`nullptr`) block from `list1`.
+
+* `sem_list2` tracks the number of blocks on `list2`.
+   * This prevents any thread from trying to read a nonexistent (`nullptr`) block from `list2`.
+
+All counting semaphores were used for thread synchronization.
+
+### Binary Semaphores:
+
+This project uses three binary semaphores:
+
+* `sem_freelist` guarantees mutual exclusion when accessing the `freelist`.
+   * This prevents memory corruption, as list accesses are thread-unsafe.
+
+* `sem_list1` guarantees mutual exclusion when accessing `list1`.
+   * This prevents memory corruption, as list accesses are thread-unsafe.
+
+* `sem_list2` guarantees mutual exclusion when accessing `list2`.
+   * This prevents memory corruption, as list accesses are thread-unsafe.
+
+All binary semaphores were used for mutual exclusion.
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