Consider a system of three cigarette smoker tasks and one...

Consider a system of three cigarette smoker tasks and one agent task. Each smoker continuously makes a cigarette and smokes it. To make a cigarette three ingredients are needed: tobacco, paper and matches. One of the tasks has paper, another tobacco and the third has matches. The agent has an infinite supply of all three ingredients. The agent places two ingredients, chosen randomly, on a table. The smoker who has the remaining ingredient can then make and smoke a cigarette. Once it has finished smoking the smoker signals the agent who then puts another two of the three ingredients on the table, and the cycle repeats. Sketch the structure of a monitor which will synchronize the agent and all three smokers.

Consider a system of three cigarette smoker tasks and one agent task. Each smoker continuously makes a cigarette and smokes it. To make a cigarette three ingredients are needed: tobacco, paper and matches. One of the tasks has paper, another tobacco and the third has matches. The agent has an infinite supply of all three ingredients. The agent places two ingredients, chosen randomly, on a table. The smoker who has the remaining ingredient can then make and smoke a cigarette. Once it has finished smoking the smoker signals the agent who then puts another two of the three ingredients on the table, and the cycle repeats.
Sketch the structure of a monitor which will synchronize the agent and all three smokers.

Key Concepts

Monitor

A monitor is a synchronization construct that provides a mechanism to control access to shared resources by multiple processes. It encapsulates the shared resource and its related operations, ensuring that only one process can be executing inside the monitor at any one time, thus preventing data races and preserving mutual exclusion.

Condition Variables

Condition variables are used within monitors to enable processes to wait for particular conditions to be met without busy waiting. They allow a process to suspend execution (wait) and later be resumed (signaled) when some condition on the shared data changes, facilitating coordination between concurrent processes.

Mutual Exclusion

Mutual exclusion is a principle used to prevent concurrent processes from entering critical sections of code simultaneously. In the context of monitors, it guarantees that while one process is accessing or modifying shared resources, no other process can perform conflicting operations, thereby maintaining consistency and preventing race conditions.

Synchronization

Synchronization involves coordinating the execution order of multiple tasks to ensure correctness when they access shared resources. In concurrent systems, proper synchronization mechanisms like monitors and condition variables are essential to orchestrate the activities of producers and consumers or any interacting tasks.

Producer-Consumer Problem

The producer-consumer problem is a classic synchronization challenge where producers generate data or resources and consumers use them. It requires careful coordination to ensure that producers do not overwhelm the system and consumers wait appropriately for the resources to be available. The monitor construct, with its built-in mutual exclusion and condition variables, is often used as a solution strategy for such problems.

Transcript

Please give Ace some feedback