Software Revision Notes

Purpose of an Operating System

An operating system (OS) serves as the core software that enables a computer to function. Its primary purpose is to manage hardware and software resources, provide common services for applications, and create an interface for users to interact with the machine. It abstracts the complexity of hardware, allowing software developers to write programs without needing to understand the intricate details of underlying hardware components.

Key Functions of an Operating System

The OS performs several critical functions: File management involves organising, storing, and retrieving files, as well as managing directories. Process management handles the execution of programs, allocating CPU time and memory to different tasks, and switching between them efficiently. Peripheral management controls and coordinates input/output devices like printers, keyboards, and mice. User management deals with user accounts, authentication, access permissions, and session tracking, ensuring system security and personalization.

File Management

File management functionality ensures data is stored, retrieved, and organised effectively. The OS handles tasks like creating, deleting, copying, moving, and renaming files and folders. It also manages file system structures, disk space allocation, and data integrity by keeping track of where files are located on storage devices.

Process Management

Process management is critical for running multiple programs concurrently. The OS allocates system resources, primarily CPU time and memory, to various processes. It handles scheduling, switching between processes (context switching), synchronisation between processes, and termination of processes. This ensures efficient use of the CPU and responsiveness of the system.

Peripheral Management

Peripheral management involves controlling and mediating access to all hardware devices connected to the computer. This includes input devices (keyboard, mouse), output devices (monitor, printer), and storage devices (hard drives, USB drives). The OS uses device drivers to communicate with these peripherals, translating requests from applications into commands that devices understand.

User Management

User management focuses on enabling multiple users to interact with the system securely and efficiently. It includes user account creation and deletion, authentication (login processes), setting and enforcing access permissions to files and resources, and managing user profiles. This ensures data privacy and system security within a multi-user environment.

Importance of Robust Software

Robust software is crucial because it ensures reliability and stability, even when faced with unexpected conditions or errors. It minimises system downtime, prevents data loss, and enhances user trust. For security, robust design reduces the attack surface for malicious actors, by handling invalid inputs gracefully and without unintended side effects. This leads to better user experience and reduced maintenance costs.

Methods for Identifying Vulnerabilities

Identifying vulnerabilities is key to software security and quality. Two primary methods are audit trails and code reviews. Audit trails, or activity logs, record system events, user actions, and changes to data, which can help detect suspicious activities or errors post-event. Code reviews involve systematically checking source code by other developers for bugs, security flaws, adherence to coding standards, and logical errors. Both methods aim to proactively find and fix issues before deployment or reactively understand incidents.

Purpose of Utility Software

Utility software helps manage, maintain, and optimise computer functions for improved performance and security. It acts as a supportive layer to the operating system, addressing common computing challenges.

Types and Functionality

File repair utilities fix corrupted files, such as those damaged during power outages. Backup software creates copies of data, often on external drives or cloud storage, for disaster recovery. Data compression reduces file sizes to save storage space and bandwidth, using algorithms like Huffman coding or Lempel-Ziv. Disk defragmentation rearranges fragmented data on a hard drive to speed up access times. Anti-malware protects systems by detecting and removing viruses, worms, and other malicious software.