4.1 Operating systems
In this part, we are going to study the operating systems and very basic concepts of how they work inside computers.
Now let’s start!
OVERVIEW
- Definition of OS
- Functions of OS
- Variations of OS
- Single-user Multi-tasking Operating System
- Polling
- Powering up
- Why is OS not needed in small devices?
What is an Operating System(OS)?
- OS makes it possible for users to communicate with softwares and hardwares (just like a translator or interface)
- Runs in background and manages many basic functions
—This a list of functions from the course book, with my translation—
White ones are safer to write in exams
Extra Information (beyond syllabus but helps to understand):
- Multiprogramming means a parallel execution of multiple tasks at the same time.
- Multitasking allows more than one task to advance over a given period of time (new task interrupt the running task and the system saves the state of the running task)
Single-user multitasking operating system
- Only one user can use the computer at a time although there can be multiple users
In contrast, many user can log into our website and read articles at the same time. - Can have many application/software open simultaneously
- Example: Windows, MacOS, Android, iOS
Polling
- The process when computers repeatedly checks the status of low-level hardware devices
- It’s a continuous and synchronous activity
- The status is actually the “readiness” or connectivity
Here is a picture I made to help you understand how computers power up:
Why don’t some small devices with embedded microprocessors have an operating system?
It’s actually quite simple
- The devices only carry out single tasks that don’t vary
- The tasks are only simple hardware functions that doesn’t need an OS to control
- The input is usually as simple as button press or screen touch