Print this chapterPrint this chapter

OPERATING SYSTEM NOTES

1. INTRODUCTION TO OPERATING SYSTEM

1.2. The History of Operating Systems

1st Generation (1940s–mid-1950s) — No Operating System

  • Hardware: Vacuum tubes and punch cards

  • OS Role: Non-existent

  • Programming: Done manually in machine language

  • Execution: One job at a time, manually loaded

  • Examples: ENIAC, UNIVAC

  • Key Characteristics:

    • No batch processing

    • Very limited automation

    • Human operators managed all tasks

2nd Generation (mid-1950s–mid-1960s) — Batch Processing Systems

  • Hardware: Transistors, magnetic tapes

  • OS Development: Primitive OS started appearing

  • Job Handling: Batch systems – jobs grouped and processed sequentially

  • Programming: Assembly language, Fortran, COBOL

  • Key Features:

    • Job Control Language (JCL)

    • Offline input/output (I/O) handling

    • No interaction with users during job execution

Examples:

  • IBM 7094 with IBSYS

  • General Motors OS (early batch OS)

3rd Generation (mid-1960s–1970s) — Multiprogramming and Time-Sharing

  • Hardware: Integrated Circuits (ICs)

  • Major Leap: Multitasking introduced

  • OS Evolution:

    • Multiprogramming (multiple jobs in memory)

    • Time-sharing (interactive user sessions)

  • Key Features:

    • Virtual memory

    • Spooling (Simultaneous Peripheral Operation On-Line)

    • File systems and command-line interfaces

Examples:

  • IBM OS/360

  • MULTICS (inspired UNIX)

  • CTSS (Compatible Time-Sharing System)

4th Generation (1970s–1990s) — Personal Computers and Networking

  • Hardware: Microprocessors (Intel 8080, 80286, etc.)

  • OS for PCs: Graphical User Interfaces (GUI) emerge

  • Networking: Local Area Networks (LANs)

  • Key Developments:

    • OS become user-friendly

    • Rise of commercial OS like MS-DOS, Windows

    • UNIX gains popularity for academic and enterprise use

Examples:

  • MS-DOS

  • Apple Macintosh System Software

  • Windows 1.0 to 95

  • UNIX (AT&T, BSD variants)

5th Generation (1990s–present) — Distributed, Mobile, and Cloud OS

  • Trends:

    • Mobile computing (smartphones, tablets)

    • Distributed systems and cloud computing

    • Virtualization and containerization (e.g., Docker)

  • Key Features:

    • Multicore and parallel processing

    • Real-time and embedded OS

    • Internet-connected devices (IoT)

Examples:

  • Windows NT to Windows 11

  • Linux (Ubuntu, Red Hat, Android)

  • macOS, iOS

  • Android OS

  • Cloud OS: Google Fuchsia, ChromeOS

6th Generation (Emerging/Future) — AI-Driven and Quantum OS

  • Possibilities:

    • AI-integrated OS for context-aware systems

    • OS for quantum computing

    • Edge computing and real-time analytics

  • Research Areas:

    • Self-healing systems

    • Predictive performance tuning

    • Autonomic computing