Operating Systems: Core Functions, History, and Key Components

Posted on Sep 7, 2025 in Computers

Operating Systems: Definition and Purpose

An Operating System (OS) is a program or set of computer programs designed for effective resource management. It manages the machine’s hardware from the most basic levels, enabling user interaction.

Essential Functions of an Operating System

The OS enables and simplifies computer management, performing several essential functions, each typically handled by a specific internal component:

  1. Provide User Comfort and Efficiency: Ensures efficient use of computer resources.
  2. Manage Equipment and Processes: Oversees equipment to run user interface processes and services.
  3. Execute Instructions: Facilitates the execution of instructions (commands).
  4. Enable Evolutionary Changes: Allows changes due to the OS’s development without interfering with already provided services.
  5. Provide the User Interface: This interaction allows programs to be loaded, files accessed, and other tasks performed. There are three main types of interfaces:
    • Command-line
    • Menu-driven
    • Graphical

Core OS Management Components

Resource Management

Manages hardware, networks, and information systems, including the CPU, memory, secondary storage devices, and remote I/O.

File Management

Contains programs for file management that control the creation, deletion, and access of files. It also involves managing data and tracking the physical location of files on storage devices.

Task Management

Manages the execution of computing tasks for end-users. It controls which program areas have access to the CPU and for how long. It can distribute and specify CPU time for a particular task, and interrupt the CPU at any time to replace it with a higher priority task.

Support Utilities

These depend on the specific implementation of the OS being used. Support includes:

  • Version updates
  • Security enhancements
  • Inclusion of new utilities
  • Drivers for new peripherals
  • Software bug fixes

Historical Perspective of Operating Systems

The first large machines (1945-1950) operated from a master console for sequential programs. During the 1950-60 decade, advances in hardware like card readers, printers, and magnetic tapes led to corresponding advances in software: compilers, assemblers, loaders, and device handlers.

Early Problems and Solutions

The primary problem was the low utilization of these early systems. The first solution involved a professional operator managing the system, which reduced setup time and increased processing speed.

The advent of spoolers (Simultaneous Peripheral Operations Online) and magnetic disks offered new solutions to emerging performance issues. Magnetic tapes, used for dumping data from slower devices, were replaced by overlapping disk operations. This allowed the CPU to perform calculations for one job while simultaneously handling I/O for another, by creating tables on disk for different tasks, a process known as spooling.

Multiprogramming Operating Systems

Hardware with memory protection offered new solutions to the problem of overlapping performance. This allowed the CPU to calculate for one job while handling I/O for others, with several jobs residing in memory simultaneously. CPU usage is kept high by assigning it to different programs in memory.

Key Characteristics of Operating Systems

  • Define a user interface.
  • Enable hardware sharing between users.
  • Allow users to share data.
  • Plan and allocate resources among users.
  • Provide I/O services.
  • Recover from errors.

Key Resources Managed by an OS

  • Processors
  • Storage
  • I/O Devices
  • Data

The Operating System as an Interface

The OS acts as an interface between:

  • Computer programs (applications and system programs)
  • Operators/Administrators
  • Hardware
  • Users

Evolution of Operating Systems

Pre-1950s: Early Computing

Early digital electronic computers (pre-1950s) had no operating systems. Programs were typically handled bit by bit, all instructions were coded by hand, and there was full access to machine language.

1950s: First Generation Operating Systems

The first implemented OS (1950s) ran one task at a time, facilitated more fluid transitions between jobs, and marked the start of batch processing.