Chapter 5 (Section 1) Final Revision #1

Software that: • Provides a platform for applications/programs to run on. • Provides an interface between hardware and human operators (HCI). • Hides the complexity of the hardware and software from the user.

Modern OSs are very large. Loading the full OS into RAM would negatively affect system performance — only the kernel and essential components are loaded; the rest is loaded on demand.

• Allows the user to communicate with the hardware by making navigation easier (hides the complexity of the OS). • Provides a facility for the user to input data. • Provides a facility for outputting information to the user. • Implemented through interface types such as a CLI, GUI, or menu-driven interface.

A text-based interface that requires the user to type specific instructions and have knowledge of the available commands to perform tasks.

A type of HCI that allows users to interact with the computer using icons and symbols (visual elements) instead of typed commands.

Windows, Icons, Menus, and Pointing device.

They use touch-screen technology and finger gestures (e.g. pinching, rotating, swiping) instead of a pointing device.

A CLI offers direct communication with the computer without being restricted to pre-determined options — power users can perform actions and chain commands that a GUI may not expose.

• Memory Management. • Security Management. • Process Management. • Hardware Management. • File Management.

The part of the OS that controls and manages main memory. Subtasks: 1. Memory protection. 2. Use of virtual memory. 3. Allocates and deallocates memory to processes. 4. Manages location of processes within memory. 5. Controls the movement of data between RAM, processor, and virtual memory.

• RAM is assigned into blocks. • Dynamic allocation of RAM to programs/processes reclaims unused blocks of RAM. • Prevents two programs/processes occupying the same area of RAM at the same time. • Moves data from secondary storage when needed // manages paging, segmentation and virtual memory.

• Single (contiguous) allocation: All memory is allocated to a single application. • Partitioned allocation: Memory is divided into contiguous blocks of variable size, each assigned to an application. • Paged memory: Similar to partitioned, but each partition (page) is a fixed size. • Segmented memory: Memory blocks are NOT contiguous; each segment is a logical grouping of data (e.g. an array).

A function that ensures two applications cannot use the same memory locations at the same time, preventing crashes and data loss.

• OS updates: keeps the system secure by installing updates as available. • Antivirus/security software updates. • Firewall communication: monitors all incoming and outgoing traffic and checks for suspicious files. • User privileges: restricts access using accounts, passwords, and UserIDs. • Access rights: manages access permissions for all users. • Data recovery and system restore. • Prevention of illegal intrusion / providing authentication — validates users and processes. • Carries out auditing and keeps logs of activity.

The part of the OS involving resource allocation and permitting the sharing and exchange of data between running programs.

• Manages the scheduling of processes / decides which order to run processes. • Allows multi-tasking/multi-processing by ensuring fair access, handling priorities, and handling interrupts. • Manages the resources the processes need (e.g. allocating memory). • Enables processes to share information/data. • Prevents interference between processes / resolves conflicts. • Handles the process queue.

A program that is currently running.