COMSCI2101_OS - M2 (TYPES OF OS)

1. Batch System

2. Interactive System

3. Real-time System

4. Hybrid System

5. Embedded System

Five types/categories of Operating System

Batch systems

Date from earliest computers, when they relied on stacks of punched cards or reels of magnetic tape for input.

Batch systems

In this OS, jobs were entered by assembling the cards into a deck and running the entire deck of cards through a card reader as a group—batch.

Throughput

The efficiency of a batch system is measured in __________.

Throughput

It is the number of jobs completed in a given amount of time

Interactive Systems

Give a faster turnaround than batch systems but are slower than

the real-time systems.

Interactive Systems

They were introduced to satisfy the demands of users who needed

fast turnaround when debugging their programs.

Interactive Systems

- It required the development of time-sharing software.

- If provides immediate feedback to the user and response time can

be measured in fractions of a second.

Real-time Systems

Used in time-critical environments where reliability is key and data

must be processed within a strict time limit.

Real-time Systems

The time limit need not be ultra-fast (though it often is), but system response time must meet the deadline or risk significant consequences.
- Must be 100% responsive all of the time.

Real-time Systems

- These systems also need to provide contingencies to fail gracefully

– that it preserve as much of the system’s capabilities and data is

possible to facilitate recovery.

1. Hard real-time system

2. Soft real-time system

Two Types of Real-time Systems

Hard real-time system

A type of real-time system that can cause the whole system to fail if a deadline is missed.

Soft real-time system

A type of real-time system that only cause slow or weak performance (not a full failure) in missing a deadline.

Hybrid Systems

- Combination of batch and interactive system.
- Users can access the system and get fast responses.

- Accepts and runs batch programs in the background when the interactive load is light.

Hybrid Systems

- It takes advantage of the free time between high-demand usage of the system and low-demand times.

- Many large computer systems use this OS type.

Embedded Systems

• Computers placed inside other products to add features and capabilities.

• Each one is designated to perform a set of specific programs, which are not interchangeable among systems.

  This permits the designers to make the operating system more efficient and take advantage of the computer’s limited resources, such as memory, to their maximum.

1940s: First Generation

History of OS:

- Time when computers are based on vacuum tube technology.
- No standard operating system software.

1940s: First Generation

History of OS:

- Typical program included every instruction needed by computer to

perform the tasks requested.

- Poor machine utilization

- Computers are the size of classrooms

- Compilers and Assemblers

Dr. Grace Hopper

She is credited with discovering the first actual computer "bug" in 1947, which was a moth trapped in a computer relay, leading to the popularization of the term "debugging."

1950s: Second Generation

History of OS:

- Focused on cost effectiveness of the system.
- Developed to meet the needs of new markets – government and business researchers.

1950s: Second Generation

History of OS:

Computers were expensive in this time.

- Two widely adopted improvements

- Computer operators were hired to facilitate machine operations.

- Concept of job scheduling: group together programs with similar requirements.

- Expensive time lags between CPU and I/O devices.

1950s: Second Generation

History of OS:

- Job scheduling introduced the need for control cards, which

defined the exact nature of each program and its requirements.

- First use of a job control language.

1950s: second generation

History of OS:

- Speed of I/O increased

- Blocking

- Buffering

- Spooling

• 1960s: third generation

History of OS:

- Faster CPUs

- Speed still caused problems when they interacted with printers

and other I/O devices that ran at slower speeds.

• 1960s: third generation

History of OS:

- The solution was multiprogramming, which introduced the

concept of loading many programs at one time and sharing the

attention of a single CPU.

- Active multiprogramming
- Passive multiprogramming

Intrerrupt

- The most common mechanism for implementing

multiprogramming was the introduction of the concept of the

__________.

Active multiprogramming

This type of multiprogramming occurs when the operating system interrupts a job process to switch between tasks.

Passive multiprogramming

This type of multiprogramming occurs when the operating system waits for each job to finish and does not control the interrupts.

1970s

History of OS:

- Main memory physical capacity limitations

- Multiprogramming schemes used to increase CPU

- Virtual memory developed to solve physical limitation

1970s

History of OS:

- Database management software

- Became a popular tool because it organized data in an

integrated manner, minimized redundancy, and simplified

updating and access of data.
- Programs started using English-like words, modular structures,

and standard operations

Firmware,

a word used to indicate that a program is permanently

held in read-only memory (ROM).

Multiprocessing

refers to having more than one processor.

1980s

History of OS:

- Cost/performance ratio improvement of computer components.

- Hardware was more flexible, with logical functions built on easily

replaceable circuit boards.
- More complex languages were designed to coordinate the

activities of the multiple processors servicing a single job.

1990s

History of OS:

The overwhelming demand for Internet capability sparked the

proliferation of networking capability.

Tim Berners-Lee

The World Wide Web by ___________ made the internet

accessible by computer users worldwide.

1990

History of OS:

Introduced a proliferation of multimedia applications demanding

additional power, flexibility, and device compatibility for most

operating systems.

2000s

History of OS:

- Primary design features support:

- Multimedia applications

- Internet and Web access

- Client/server computing

2000s

History of OS:

- Computer systems requirements

- Increased CPU speed

- High-speed network attachments

- Increased number and variety of storage devices

2000s

History of OS:
- Virtualization

- Single server supports different operating systems

Object-Oriented Design

An important area of research that resulted in substantial efficiencies

was that of the system architecture of operating systems.

The way their components are programmed and organized, specifically

the use of object-oriented design and the reorganization of the

operating system’s nucleus, the kernel.

kernel.

It is the part of the operating system that resides in memory at all times, performs the most essential operating system tasks, and is protected by hardware from user tampering.