C2. Operating System & Application Software

Operating System

— the most important program on a computer. It controls the computer’s hardware resources and creates an environment for application programs to execute efficiently.

  • The Manager Analogy - OS organizes the computer’s hardware, allocates system resources, and ensures different programs play nicely together.

What Happens When You Power On

  1. Verifies Hardware - checks all hardware components are functioning correctly

  2. Initializes Resources - setup system resources so programs can use them safely

  3. Offers the Interface - presents the GUI for the user to interact with

Functions

  • Handling Processing - running many apps at once — the OS divides the processor’s time among applications so they all function without interfering with each other.

  • Handling Memory - OS keeps track of memory usage, provides memory to apps as needed, and releases it when programs close.

  • File I/O - organizes all the documents, images, videos, and applications saved on the computer. Ensures data is retrievable when required

  • Device Management - hardware devices interact with the OS through drivers.

  • Graphical User Interface (GUI) - icons, windows, and menus — pointing, clicking, and tapping instead of typing commands

  • Command-Line Interface (CLI) - commands are entered as text. Less visual but often faster and more powerful for experienced users.

Types of OS

  • Batch OS - handles groups of similar tasks without constant user intervention. Jobs are queued and executed in a specific sequence. For repetitive ops like payroll, billing, and financial reporting.

  • Time-Sharing OS - enables several users to use the same computer system simultaneously. Common in institutions, businesses, and server environments.

  • Distributed OS (DOS) - collection of computers connected to form a single system. PCs are physically separated yet work together to share processing power, storage, and resources.

  • Real-Time OS - for applications that require an immediate reaction. It processes info under strict time constraints to avoid delays. Ex. Air Traffic Control, Robotics and Industrial Automation, Medical Monitoring Devices, and Automotive Control Systems

  • Mobile OS - made for mobile devices such as smartphones, tablets, and wearables

Common OSs

  • Windows - most utilized OS in the world. Typically used for office productivity, programming, multimedia editing, and gaming.

  • macOS - OS for Apple computers. User-friendly and apple ecosystem. Reliable and secure, and optimized performance and professional-grade software.

  • Linux/GNU - free, open-source, and built by a global community. Highly flexible and customizable. Foundation for web and DB servers, cloud computing platforms, cybersecurity systems, software dev environments, and world’s fastest supercomputers.

  • Android - Google’s mobile OS and most widely used smartphone OS. Open-source

  • iOS - Apple’s mobile OS. smooth performance, strong security, and tight integration with Apple’s hardware and services. Less flexible than Android.

System Software

— controls the computer itself, the environment in which application programs run.

  • OS

  • Device Drivers

  • Utilities

  • Disk Management Utilities

  • Anti-virus Software

Application Software

— designed to enable to perform specific tasks.

  • MS Word/Excel/PPT

  • Google Chrome

  • Adobe Photoshop

  • AutoCAD

  • Zoom

  • VLC Player

!OS makes the computer work, and application software enables users to do something useful.

Software Licensing

  • Freeware - can be downloaded and used at no cost. Users can use the software freely, but usually cannot edit the source code. Ex. Adobe Acrobat Reader, VLC Media Player

  • Shareware - Software you can try before you buy. Trial versions typically have limited features or time limits. Ex. WinRAR

  • Free/Open-Source Software - enables users to review, modify, and distribute the source code of a program. Enables collaboration and progress. Ex. Linux, LibreOffice, GIMP, Mozilla Firefox

  • Commercial Software - developed for commercial purposes and copyright-protected. Users are required to have a license to use the software legally. Ex. Microsoft Office, Adobe Photoshop, AutoCAD