What is Operating System

✅ Operating System

collection of software that manages computer hardware resources and provides common services for computer programs
> communication channel between system hardware and system software

• windows 10
• UNIX
• MS-DOX
• LINUX: OS for servers

☑️ Purpose of OS

• thouroughput ⬆️

  • how much work a system can manage in certain time
  • 일을 얼마나 헀는가

• turn around time ⬇️

  • time it takes from request until the job is finished
  • 일하는데 시간 얼마나 걸렸니

• availability ⬆️

  • 시스템 사용하려고 할 때 즉시 사용 가능한 정도

• reliability ⬆️

  • 시스템이 주어진 문제를 정확하게 해결하는 정도

☑️ Functions of OS

1. Processor Management

• start, stop, manage process, program
• ⭐️ scheduling
• ⭐️ processing, thread
• ⭐️ synchronization
• ⭐️ IPC communication

2. Memory Management

• ⭐️ manage primary memory
• optimize memory use
• ⭐️ virtual memory
• ⭐️ file system

3. Networking

• establish, manange network connections
• network protocols
• share files, printers over network
• ⭐️ TCP/IP

4. User Interface

• interface for users to interact w the computer
• GUI: Graphical User Interface
• CLI: Command Line Intereface

5. Device Driver

• ⭐️ 순차접근 장치
• ⭐️ 임의접근 장치
• ⭐️ 네트워크 장치

☑️ Detailed Explanation of functions

1. Processor Management

• Processor Scheduling
  • determines which process has access to processor
  • how much processig time each process has
• Process
  • keep track of status of process
  • traffic controller
  • allocates CPU to process
  • when process is no longer required, de-allocates

2. Memory Management

• for a program to be run, needs to be loaded in the main memory
• OS manages allocation, deallocation of memory

3. Networking

• Network communication
  • cops for internet traffic
  • manage how data is packaged and sent over a network
  • check if the data arrived safely and in correct order
• Settings and Monitoring
  • network connections(WIFI)

4. User Interface

user ➡️ OS ➡️ computer interface
high level language ➡️ interpreter ➡️ machine language

5. Device Driver

• manages hardware
• decide which process gets acess to a certain device and for how long, and deallocate

6. Job Accounting

• if more than one user is using the OS
• track resource usage of particular user
• determine which application should run in which order, allocation

7. Virtual Caculator

⭐️ Virtual Caculator

• one computer to function as several computers