Operation Sytem 6

• Operating System (OS)


  An interface that connects the user (brainware) with computer hardware
• In the past, humans could only operate computers using signals
• Operating system


  • Manages hardware components
  • Allocates memory and processing power
  • Handles input/output operations
  • Provides a user interface for interacting with the system
• Computer system


  A broader term that includes all the hardware and software that work together to perform a specific task
• Computer system


  • Laptop
  • PC
  • Cell phone
• Operating system


  A specific type of software that acts as "core" software that manages computer system resources and provides a platform for other software to run
• Operating systems


  • Windows
  • Linux
  • Mac OS
  • Android
• Studying operating systems can help us to maximize and optimize OS usage, choose the most suitable OS for our purposes, modify existing operating systems to suit with our goals, and even create our own OS
• Purpose of an OS

  • Convenience: makes using and operating a computer easier
  • Efficiency: so that resources in a computer system can be used as efficiently as possible
  • Evolvability: allows easier development, testing and deployment of new systems when developing operating systems
• Evolution of Operating Systems

  1. First Generation (1945 – 1955)

  2. Second Generation (1955 – 1965)

  3. Third Generation (1965 – 1980)

  4. Fourth Generation (1980 – present)
• In the First Generation (1945 – 1955), there was no operating system invented yet, so humans still gave every instruction directly and manually to the computer using assembly language
• In the Second Generation (1955 – 1965), Batch Processing System was introduced and some computers started to be equipped with OS
• In the Third Generation (1965 – 1980), the OS was developed to handle multiple users simultaneously, where the users interact interactively with the computer via an online terminal
• In the Fourth Generation (1980 – present), OS has been widely used in computer networks where users can recognize other computers or users who are also connected and connected to each other, and the era of distributed computing has just begun
• Operating System Services


  • Program creation
  • Program execution
  • I/O device access
  • Controlled access to files
  • System access
  • Access functions
  • Error detection and response
  • Accounting
• Computer structure


  The way each component is related to each other
• Components of computer structure

  • Computer operating system
  • I/O structure
  • Storage structure
• When a computer is started for the first time (when booting), there will be an initial program that must be run which is called the bootstrap program
• Interruptions are an important part of computer system architecture, and can occur when hardware or software requests to be "served" by the processor
• Synchronous I/O

  Control is returned to the user process once the I/O process is complete
• Asynchronous I/O


  Control is returned to the user process without waiting for the I/O process to complete so that the I/O process and the user process can run simultaneously
• Direct Memory Access (DMA) structure

  An I/O management method in which the device controller connects directly to memory without CPU intervention
• Computer programs must be loaded in main memory (usually RAM) in order to run
• Main memory


  A storage area that can be accessed directly by the processor, but is volatile and cannot be stored permanently
• Registry


  A storage area that can be accessed directly by the processor, and is the fastest storage medium compared to main memory
• Cache


  A storage buffer created to overcome the speed difference between the registry and main memory
• Magnetic Disks


  Act as secondary storage in modern computer systems, consisting of platters covered with magnetic material and divided into rotating tracks and sectors
• Operating system development is significantly influenced by hardware developments, and as hardware develops and becomes more sophisticated, so do operating systems
• Components in Modern OS


  • Process Management
  • Main Memory Management
  • Secondary Storage Management
  • I/O Device Management
  • I/O System Management
  • File Management
  • Protection System
  • Command Interpreter System
• Process

  The state when a program is being executed, requiring resources like CPU time, memory, files, and I/O devices
• Process Management


  • Create and delete user processes and system processes
  • Suspend or resume the process
  • Provides a mechanism for process synchronization
  • Provides a mechanism for process communication
  • Provides a mechanism for handling deadlocks
• Main memory

  A large array of words or bytes, used as a temporary storage area by the CPU or I/O devices
• Main Memory Management


  • Track memory in use and who is using it
  • Selects the program to be loaded into memory
  • Allocate and reallocate memory space as needed
• Secondary storage

  Permanent storage for data and computer programs, larger than main memory
• I/O Device Management


  Provides a common "device driver" so that I/O operations can be uniform
• I/O System Management


  • Buffer: temporarily stores data from/to I/O devices
  • Spooling: scheduling the use of the I/O system to make it more efficient
  • Provides drivers to be able to perform "detailed" operations for specific I/O hardware
• File


  A collection of related information according to the purpose of the file creator, with a hierarchical structure
• File Management


  • File creation and deletion
  • Directory creation and deletion
  • Supports file and directory manipulation
  • Map files to secondary storage
  • Back up files to permanent storage media
• Protection

  Mechanisms for controlling access by programs, processors, or users to system resources
• Command Interpreter System

  Programs that read instructions and interpret control statements, varying greatly between operating systems