DSAC-11 Annex B Practice Test

Protecting the system from both external and internal threats is what an operating system does. It acts as a security boundary that enforces who can access what, and under what conditions. The OS implements access controls, authentication, and authorization so that only legitimate users and processes can touch files, devices, and memory. It isolates processes from one another, provides memory protection, and mediates interactions through controlled interfaces, preventing careless or malicious actions from one part of the system from compromising others. These mechanisms address threats coming from outside the computer (like network attackers) and from within (like a compromised user account or a misbehaving program).

It's important to note that no system is completely immune to malware; threats can still exploit vulnerabilities or social engineering, which is why updates and additional security layers (such as antivirus and intrusion detection) are also necessary. Hardware-level encryption is just one piece of security and doesn’t encompass the full set of protections the OS provides.