Introduction to Operating Systems

Operating System Components

• An Operating System (OS) acts as an intermediary between the user and computer hardware.
• The OS is a set of software routines that sit between the application program and hardware.
• The OS performs key support functions such as:
  • Communicating with peripheral devices
  • Accepting and carrying out user commands (e.g., loading a program, copying a file, creating a directory)

Four Components of Computer System

• Hardware: provides basic computing resources (CPU, Memory, I/O Devices)
• Application Program: defines the ways in which resources are used to solve computing problems (e.g., compilers, database systems, games, business programs)
• Users: the people and machines that solve problems using various application programs
• Operating System: controls and coordinates the use of hardware among various application programs and users

Purpose and Goals of Operating System

• To provide an environment in which a user can execute programs
• To make computer systems convenient to use
• To use computer hardware efficiently

Functions of Operating System

• As a Service Provider: provides an environment for programs to execute
• As a Resource Manager: manages and allocates resources (e.g., CPU, Memory, I/O Devices)

Resource Management

• Creation and deletion of user and system processes
• Suspension and resumption of processes
• Provision of mechanisms for:
  • Process synchronization
  • Process communication
  • Deadlock handling

I/O Manager

• Involves file and I/O devices

File Manager

• Manipulation of data
• Execution of data
• Recovery and archiving

Protection and Security

• Ensures controlled access to system resources
• Includes security measures, such as password authentication

Accounting

• Keeps track of resources and their usage

Error Detection and Handling

• Constantly monitors for possible errors

History of Operating Systems

• 0th Generation: No OS, machines controlled through hard-wired punch cards (1950s)
• 1st Generation: Simple OS, batch processing, stored programs (1950s)
• 2nd Generation: Multi-using, simultaneous program storage, resource sharing (1960s)
• 3rd Generation: Multiprocessing, multiprogramming, time-sharing, real-time processing, virtual memory (1960s)
• 4th Generation: Networking systems, distributed OS, open systems (1970s-1980s)
• 5th Generation: Multimode systems, high-resolution, speech synthesis, computer vision, open systems (1980s)