Introduction to Operating Systems

Operating System Overview

• An Operating System (OS) acts as an interface between users and computer hardware.
• Performs essential tasks such as file management, memory management, process management, handling input/output, and controlling peripheral devices.

Popular Operating Systems

• Notable OS examples include:
  • Linux
  • Windows
  • VMS
  • OS/400
  • AIX
  • z/OS

Objectives of Operating Systems

• Convenience: Enhances user experience by allowing convenient access to the computer system.
• Efficiency: Optimizes the use of computer resources for better performance.
• Ability to Evolve: Supports the development and testing of new functions without disrupting existing services.

Key Functions of an Operating System

• Memory Management
• Process Management
• Device Management
• File Management
• Security measures
• Control over system performance
• Job accounting
• Error detection
• Coordination between software and users

Process Management

• In multiprogramming, the OS schedules processes, deciding:
  • Which process gets CPU time and for how long.
• Maintains status and tracking of all processes with the assistance of the traffic controller.
• Responsible for:
  • Allocating CPU to processes.
  • De-allocating CPU when processes are finished.

Device Management

• Manages device communication via respective drivers.
• Tasks include:
  • Tracking all devices using the I/O controller.
  • Scheduling device access for processes.
  • Efficient allocation and de-allocation of devices.

File Management

• Organizes the file system into directories for user-friendly navigation.
• Responsibilities include:
  • Keeping track of file information, location, and usage.
  • Managing resource allocation and de-allocation for files.

Security

• Implements security techniques such as passwords to prevent unauthorized access to programs and data.

Control Over System Performance

• Monitors response times for service requests to ensure efficient performance.

Job Accounting

• Records time and resource usage for various jobs and users for administrative purposes.

Error Detection

• Produces data for debugging, including dumps, traces, and error messages to assist in identifying problems.

Coordination between Software and Users

• Manages the allocation of various compilers, interpreters, and assemblers to users, ensuring effective use of software resources.