Access Control Lists (ACLs) in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an Access Control List (ACL)?

An Access Control List (ACL) is a list that tells a computer system who can access certain files or resources and what actions they can perform, like reading or writing.

intermediate

How does an ACL differ from traditional file permissions?

Traditional file permissions usually allow access based on user, group, or others with fixed rights. ACLs provide more detailed control by specifying permissions for multiple users or groups individually.

beginner

Name two common types of permissions that can be set in an ACL.

Two common permissions are 'read' (view the content) and 'write' (modify the content). Others include 'execute' (run a file) and 'delete'.

beginner

Why are ACLs important in multi-user operating systems?

ACLs help protect files and resources by controlling exactly who can do what, preventing unauthorized access and keeping data safe when many users share the system.

beginner

Can ACLs be used to allow access to a specific user while denying others?

Yes, ACLs can specify permissions for individual users, allowing some users access while denying others, providing flexible and precise control.

What does an Access Control List (ACL) primarily control?

A Who can access a resource and what actions they can perform

B The speed of the computer processor

C The color scheme of the user interface

D The amount of memory used by an application

ACLs define which users or groups can access resources and what they are allowed to do.

Which of the following is NOT a typical permission in an ACL?

A Print

B Write

C Execute

D Read

Print is not usually a permission controlled by ACLs; common permissions include read, write, and execute.

How do ACLs improve security compared to basic file permissions?

A By encrypting files automatically

B By speeding up file access

C By deleting unused files

D By allowing detailed permissions for multiple users and groups

ACLs allow setting specific permissions for many users or groups, offering more precise control.

In a multi-user system, why is ACL important?

A To speed up the internet connection

B To control who can access files and what they can do

C To improve the graphics display

D To increase the number of users

ACLs protect resources by managing user access and permissions.

Can ACLs specify permissions for individual users?

A No, ACLs only work for groups

B No, ACLs only control network access

C Yes, ACLs can assign permissions to specific users

D Yes, but only for administrators

ACLs allow permissions to be set for individual users as well as groups.

Explain what an Access Control List (ACL) is and why it is useful in operating systems.

Think about how computers decide who can open or change files.

Describe the difference between traditional file permissions and ACLs.

Consider how flexible the control is in each method.