Operating Systems Chapter 2

Types of Operating Systems

• Operating systems classify into five categories based on response time and data entry methods: batch, interactive, real-time, hybrid, and embedded.

Batch Systems

• Originated with early computers using punched cards or magnetic tape for input, processing jobs in groups.
• Efficiency is measured by throughput, e.g., 550 jobs per hour.

Interactive Systems

• Provide faster response times than batch systems but slower than real-time systems.
• Developed for users requiring quick feedback, especially for debugging.
• Features time-sharing software for immediate responses, often measured in fractions of a second.

Real-time Systems

• Critical in environments requiring high reliability and adherence to strict time limits.
• Must meet deadlines to avoid serious consequences; response time often needs to be ultra-fast.
• Incorporate fail-safe mechanisms to recover data and preserve capabilities.

Types of Real-Time Systems

• Hard real-time systems: Total system failure occurs if deadlines are missed.
• Soft real-time systems: Performance degradation happens, but does not lead to complete failure if deadlines are missed.

Hybrid Systems

• Combine batch and interactive systems, allowing for quick user access and background batch processing.
• Optimize idle times during low-demand usage periods.
• Common in large computer systems.

Embedded Systems

• Integrated within other products to enhance their features, found in appliances, cars, music players, elevators, and medical devices.
• Designed for specific applications with non-interchangeable programs to maximize efficiency and utilize limited resources effectively.

Brief History of Operating Systems Development

• 1940s: First Generation

  • Utilized vacuum tube technology with no standard operating systems.
  • Programs comprised all instructions for task execution, leading to poor CPU utilization (limited active processing time).

• 1950s: Second Generation

  • Emphasized cost-effectiveness, targeting government and business markets.
  • Highlighted the introduction of computer operators and job scheduling to enhance efficiency.
  • Job control language was first used to specify program requirements, improving system management and operation.

Types of Operating Systems

• Operating systems classify into five categories based on response time and data entry methods: batch, interactive, real-time, hybrid, and embedded.

Batch Systems

• Originated with early computers using punched cards or magnetic tape for input, processing jobs in groups.
• Efficiency is measured by throughput, e.g., 550 jobs per hour.

Interactive Systems

• Provide faster response times than batch systems but slower than real-time systems.
• Developed for users requiring quick feedback, especially for debugging.
• Features time-sharing software for immediate responses, often measured in fractions of a second.

Real-time Systems

• Critical in environments requiring high reliability and adherence to strict time limits.
• Must meet deadlines to avoid serious consequences; response time often needs to be ultra-fast.
• Incorporate fail-safe mechanisms to recover data and preserve capabilities.

Types of Real-Time Systems

• Hard real-time systems: Total system failure occurs if deadlines are missed.
• Soft real-time systems: Performance degradation happens, but does not lead to complete failure if deadlines are missed.

Hybrid Systems

• Combine batch and interactive systems, allowing for quick user access and background batch processing.
• Optimize idle times during low-demand usage periods.
• Common in large computer systems.

Embedded Systems

• Integrated within other products to enhance their features, found in appliances, cars, music players, elevators, and medical devices.
• Designed for specific applications with non-interchangeable programs to maximize efficiency and utilize limited resources effectively.

Brief History of Operating Systems Development

• 1940s: First Generation

  • Utilized vacuum tube technology with no standard operating systems.
  • Programs comprised all instructions for task execution, leading to poor CPU utilization (limited active processing time).

• 1950s: Second Generation

  • Emphasized cost-effectiveness, targeting government and business markets.
  • Highlighted the introduction of computer operators and job scheduling to enhance efficiency.
  • Job control language was first used to specify program requirements, improving system management and operation.