Operating Systems

Information about using

• Linux

• Bash

• Scripting

• etc

What is an Operating System?

• An Operating System (OS) is a collection of software that manages computer hardware and provides services for programs.

  • it hides hardware complexity,

  • manages computational resources

  • provides isolation and protection.

  • it directly has privilege access to the underlying hardware.

• Major components of an OS are

  • the file system

  • scheduler

  • device driver.

• three key elements of an operating system

  • (1) Abstractions (process, thread, file, socket, memory)

  • (2) Mechanisms (create, schedule, open, write, allocate)

  • (3) Policies (LRU, EDF)

• two operating system design principles

  • (1) Separation of mechanism and policy by implementing flexible mechanisms to support policies

  • (2) Optimization for common case:

    • Where will the OS be used?

    • What will the user want to execute on that machine?

    • What are the workload requirements?

• three types of Operating Systems commonly used nowadays.

  • Monolithic OS

    • where the entire OS is working in kernel space and is alone in supervisor mode.

  • Modular OS

    • in which some part of the system core will be located in independent files called modules that can be added to the system at run time.

  • Micro OS

    • where the kernel is broken down into separate processes, known as servers. Some of the servers run in kernel space and some run in user-space.

Concepts of Operating systems

• Processes and Process Management

• Threads and Concurrency

• Scheduling

• Memory Management

• Inter-Process Communication

• Input/Output Management

• Virtualization

• Distributed File Systems

• Distributed Shared Memory

• Cloud Computing