Resource allocation graph in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Resource Allocation Graph (RAG)?

A Resource Allocation Graph is a visual tool used in operating systems to represent the allocation of resources to processes. It shows which processes hold resources and which are waiting for resources.

beginner

What do the nodes in a Resource Allocation Graph represent?

In a Resource Allocation Graph, there are two types of nodes: circles represent processes, and squares represent resources.

beginner

What does a directed edge from a process to a resource mean in a Resource Allocation Graph?

A directed edge from a process to a resource means the process is requesting that resource and is waiting to acquire it.

beginner

What does a directed edge from a resource to a process indicate in a Resource Allocation Graph?

A directed edge from a resource to a process means the resource has been allocated to that process.

intermediate

How can a Resource Allocation Graph help detect deadlocks?

If the Resource Allocation Graph contains a cycle, it indicates a deadlock situation where processes are waiting indefinitely for resources held by each other.

In a Resource Allocation Graph, what shape represents a process?

A Square

B Circle

C Triangle

D Diamond

Processes are represented by circles in a Resource Allocation Graph.

What does an edge from a resource node to a process node signify?

A Resource is allocated to the process

B Process is requesting the resource

C Process is releasing the resource

D Resource is free

An edge from a resource to a process means the resource is currently allocated to that process.

What indicates a deadlock in a Resource Allocation Graph?

A A disconnected graph

B Only resource nodes present

C A cycle in the graph

D No edges in the graph

A cycle in the Resource Allocation Graph shows a deadlock where processes wait indefinitely.

Which of the following is NOT a component of a Resource Allocation Graph?

A Processes

B Resources

C Edges

D Memory addresses

Memory addresses are not represented in a Resource Allocation Graph; only processes, resources, and edges are.

If a process has an edge pointing to a resource, what is the process doing?

A Requesting the resource

B Releasing the resource

C Holding the resource

D Ignoring the resource

An edge from a process to a resource means the process is requesting that resource.

Explain how a Resource Allocation Graph represents processes and resources and their interactions.

Think about how the graph shows who holds or waits for what.

Describe how to detect a deadlock using a Resource Allocation Graph.

Focus on the meaning of cycles in the graph.