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UGC NET PAPER 1 · UNIT 08 · MODULE 2: DEVICES, MEMORY AND OPERATING SYSTEMS · TOPIC 6

Operating Systems

What an OS does, its types, Windows, Linux, macOS, Android and iOS, command-line versus graphical interfaces, and the basics asked repeatedly.

  • 6 sub-topics
  • 3 min read
  • Topic 6 of 18

What this topic covers

6 sub-topics, in the order to study them. Tap one to jump to it.

  1. 6.1MeaningAn operating system (OS) is system software that acts as an interface between the user and the computer hardware and manages all hardware and software resources.
    • operating system (OS)
    • booting
    • kernel
    • shell
  2. 6.2Functions of an OSCovers Process management, Memory management, File management, Device management, Security and access control and more.
    • Process management
    • Memory management
    • File management
    • Device management
    • Security and access control
  3. 6.3Types of Operating SystemsType Key idea Example or use Batch Jobs with similar needs grouped and run without user interaction Early mainframes, payroll Multiprogramming Several programs in memory…
    • Batch
    • Multiprogramming
    • Time-sharing (multitasking)
    • Real-time (RTOS)
    • Distributed
  4. 6.4Popular Operating SystemsCovers Windows (Microsoft), Linux, Unix, macOS and iOS (Apple), BOSS (Bharat Operating System Solutions).
    • Windows (Microsoft)
    • Linux
    • Linus Torvalds (1991)
    • Unix
    • macOS and iOS (Apple)
  5. 6.5User InterfacesCLI (Command Line Interface): text commands (DOS, Linux terminal).
    • CLI (Command Line Interface)
    • GUI (Graphical User Interface)
  6. 6.6Useful Basics (frequently asked)Covers File extension, Shortcuts, Folder (directory), MS Office suite.
    • File extension
    • Shortcuts
    • Folder (directory)
    • file
    • Path

Revision mode hides the full explanations and keeps each section's key terms, lists and tables and the Memory Capsule. Use it from your second read onward.

6.1Meaning#

In brief

An operating system (OS) is system software that acts as an interface between the user and the computer hardware and manages all hardware and software resources.

  • operating system (OS)
  • booting
  • kernel
  • shell

An operating system (OS) is system software that acts as an interface between the user and the computer hardware and manages all hardware and software resources. Without an OS the computer cannot run applications. The OS is loaded into RAM at booting (start-up), when the BIOS or firmware runs a power-on self-test and loads the OS from disk. The kernel is the core of the OS. The shell is the layer the user interacts with.

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6.2Functions of an OS#

In brief

Covers Process management, Memory management, File management, Device management, Security and access control and more.

  • Process management
  • Memory management
  • File management
  • Device management
  • Security and access control
  • User interface

  • Process management: scheduling the CPU, multitasking.

  • Memory management: allocating and freeing RAM, virtual memory.

  • File management: creating, naming, organising, protecting files and folders.

  • Device management: drivers for printers, keyboards and disks.

  • Security and access control: passwords, user accounts, permissions.

  • User interface: CLI or GUI.

  • Error detection, resource allocation and job accounting.

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6.3Types of Operating Systems#

In brief

Type Key idea Example or use Batch Jobs with similar needs grouped and run without user interaction Early mainframes, payroll Multiprogramming Several programs in memory…

  • Batch
  • Multiprogramming
  • Time-sharing (multitasking)
  • Real-time (RTOS)
  • Distributed
  • Network OS
  • Embedded
  • Mobile
Type Key idea Example or use
Batch Jobs with similar needs grouped and run without user interaction Early mainframes, payroll
Multiprogramming Several programs in memory, CPU switches when one waits for I/O Mainframes
Time-sharing (multitasking) CPU time sliced among many users or tasks Unix, Windows
Real-time (RTOS) Must respond within a strict deadline Air-traffic control, medical devices, missiles
Distributed Many computers appear as one system Large clusters
Network OS Manages servers and shared resources on a network Windows Server, Novell NetWare
Embedded Fixed-function device OS Washing machine, ATM
Mobile Touch-based OS Android, iOS

Single-user versus multi-user, and single-tasking versus multi-tasking are other classifications.

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6.4Popular Operating Systems#

In brief

Covers Windows (Microsoft), Linux, Unix, macOS and iOS (Apple), BOSS (Bharat Operating System Solutions).

  • Windows (Microsoft)
  • Linux
  • Linus Torvalds (1991)
  • Unix
  • macOS and iOS (Apple)
  • C-DAC
  • Maya OS

  • Windows (Microsoft): proprietary, GUI-based.

  • Linux: open-source, kernel by Linus Torvalds (1991). Distributions include Ubuntu, Fedora and Red Hat. Based on Unix ideas.

  • Unix: multi-user, multi-tasking, developed at Bell Labs in the 1970s.

  • macOS and iOS (Apple), Android (Google, Linux-based, open source).

  • BOSS (Bharat Operating System Solutions): Indian Linux-based OS developed by C-DAC. Maya OS is a Linux-based OS developed for the Indian defence sector.

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6.5User Interfaces#

In brief

CLI (Command Line Interface): text commands (DOS, Linux terminal).

  • CLI (Command Line Interface)
  • GUI (Graphical User Interface)

CLI (Command Line Interface): text commands (DOS, Linux terminal). Fast and powerful, but harder to learn. GUI (Graphical User Interface): windows, icons, menus and pointer (WIMP). Easy and intuitive. Examples are Windows and macOS. Xerox PARC pioneered the GUI.

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6.6Useful Basics (frequently asked)#

In brief

Covers File extension, Shortcuts, Folder (directory), MS Office suite.

  • File extension
  • Shortcuts
  • Folder (directory)
  • file
  • Path
  • MS Office suite
  • Traps

  • File extension identifies type: .docx (Word), .xlsx (Excel), .pptx (PowerPoint), .pdf, .txt, .jpg, .mp3, .mp4, .exe.

  • Shortcuts: Ctrl+C copy, Ctrl+X cut, Ctrl+V paste, Ctrl+Z undo, Ctrl+Y redo, Ctrl+S save, Ctrl+P print, Ctrl+A select all, Ctrl+F find, Alt+Tab switch windows, Ctrl+Alt+Del task manager options.

  • Folder (directory) versus file. Path shows the location of a file.

  • MS Office suite: Word (documents), Excel (spreadsheets, cell address, formulas such as SUM and AVERAGE), PowerPoint (slides), Access (database), Outlook (e-mail).

Traps: Linux is open source and Windows is not. Android is not a Microsoft product. The OS is system software, whereas MS Word is application software.

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Test yourself on Operating Systems

Practise with free MCQs and answer keys, then return here to fix what you got wrong.

↑ Module 2: Devices, Memory and Operating Systems · All 18 topics in ICT · Unit overview and sample MCQs

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