The museum - a concurrent programming project

This was a project for the Operating systems with concurrency programming course.

Introduction

The museum has 2 halls - A and B with limited capacity and C_A > C_B. Some of the visitors want to go to the A hall and leave, others want to visit both exhibitions. This environment was used to formulate two problems:

1. Maximize the number of visitors who visit the museum at the same time.
2. Allow people from hall B to leave the museum as fast as possible.

Solution

Problem 1

My take on the first problem was to allow the visitors to fill hall B while always leaving one spot free in hall A. This solution prevents deadlock that could occur when the visitors are trying to fill the full hall B while maximizing the number of visitors who visit the museum simultaneously. The implementation of this solution is based on the following idea:

1. Counting semaphores sem.A and sem.B initialized with respectively C_A-1 and C_B are used to control the number of visitors who can enter the specific hall.
2. A mutex mutex.B is used to allow only one visitor to leave hall B at a time.

Problem 2

For the second problem, the solution is to reserve empty spots in hall A to allow the visitors to leave hall B as fast as possible. I implemented this solution by using two semaphores sem.A and sem.B initialized with respectively C_A and C_B.