Operating Systems & Utility Software

Provides a way for users to interact with the computer. Two main types:

• GUI (Graphical User Interface) — windows, icons, menus, pointer (e.g. Windows, macOS). User-friendly, requires more resources.
• CLI (Command Line Interface) — text-based commands (e.g. Linux terminal). Faster, uses fewer resources, requires expertise.

Allocates RAM to running programs and manages how memory is used.

• Decides which programs get memory and how much
• Manages virtual memory — uses a section of the hard drive/SSD as temporary RAM when physical RAM is full
• Prevents programs accessing each other's memory space (security)

Allows multiple programs to appear to run simultaneously on a single CPU.

• The OS scheduler rapidly switches CPU time between processes
• Switches happen so fast the user perceives simultaneous execution
• True simultaneous execution only possible with multiple CPU cores

Manages communication between the OS and hardware peripherals (printers, keyboards, monitors, etc.).

• Uses device drivers — small programs that translate OS commands to device-specific instructions
• When you plug in a new device, the OS finds and loads the correct driver
• Without the driver, the OS cannot communicate with the peripheral

Manages user accounts, logins, and permissions.

• Each user has an account with a username and password
• Permissions control what files and resources each user can access
• Administrator accounts have elevated privileges
• Audit logs record who accessed what and when

Organises files on storage devices using a hierarchical directory structure (folders within folders).

• Create, delete, rename, move, and copy files and folders
• Manages file metadata (name, size, date, type)
• Controls file permissions — who can read/write/execute