Operating System
The operating system is a type of software that provides a platform through which users can interact with the computer.
It works as intermediary software between users and the hardware of the computer. The following operating system software is available to install in the system.
- Windows OS
- Mac OS
- Linux OS
- Android OS
- IOS
- Windows 10 Mobile
These are the most popular operating system that is widely used. Windows 11 is the newest OS.
Operating System helps the user to install and work with another software that is called application software. We can install like web-browser, games, video players, M.S. Office, etc.
Operating System provides an interface to the user that is GUI or Graphical User Interface. It helps to understand everything in human language with icon images. Actually, Operating System Software is kernel layer software.
Components Of Operating System
There are two main parts of the operating system
- Kernel
- User Space
Kernel
Kernel Layer has the following Management
- Process Management
- Memory Management
- File Management
- I/O Management
User Space
- Applications (Application Software)
The kernel is the middle part of the operating system. It directly connects to the hardware layer and talks to manage the system. As a user, we can't interact with the kernel directly. We can interact with the second part of the operating system which is User Space.
The userspace where we install everything that is used commonly on a daily basis. We can install application software on the kernel.
Usually, you will hear the word PC. It means Person Computer or one person uses the computer. But today PC means Windows Computer.
One another operating system is called Linux. It is an open-source operating system. Linux is used in business infrastructure. It is a kernel developed by Linus Torvalds. Some common Linux distributions are Ubuntu, Debian, CentOS, and Red Hat.
Another operating system that is more popular is called Chrome OS. It is developed by Google. Chrome OS uses the chrome browser as a user interface.
Here we will discuss only two OS
- Windows
- Linux
If you buy a pre-installed Linux system, it is more affordable. Therefore, we can install the Linux Operating system on Windows OS by using Virtual Box.
Now we will discuss Kernel:
Process Management
Process:- A process is a program that executes or runs. For example, any software like an internet browser, text editor, etc.
program:- A program is a set of instructions that do a specific task like chrome, Edge, etc.
We have many processes in the same program and we can run at the same time.
suppose you are using a chrome browser. We can open many new tabs at a time. At that time Chrome browser handles the whole process simultaneously.
Think there is only one CPU and many processes are done within a couple of milliseconds. How is it possible by CPU?
Actually, it is possible. CPU uses the time slice through which it executes the process one by one separately.
Time slice
A time slice is a very short interval of time in which a process is allocated for CPU execution. It is a very small time. CPU executes the process in milliseconds then it executes another process.
Memory Management
When a process is run, it takes some time and space in memory. It doesn't take up space on the hard disk drives. Since many processes are run by the CPU so more memory is required.
For that, these are stored in virtual memory. Virtual Memory is the combination of a Hard drive and RAM and acts as a memory.
When you execute a process, the data of the program is stored in chunks. These chunks are called pages and these pages are stored in virtual memory. When the pages are required to execute and read, these pages are sent to the physical memory that is called RAM.
Now CPU gets the page's data from RAM and shows it to the user.
Characteristics of virtual memory
- Virtual Memory stores those pages that are not used currently by Physical memory or RAM.
- Virtual Memory gives them permission to extend the space of physical memory or RAM on a computer.
- It is the combined form of RAM and Hard disk space.
- It allows the computer to have more memory than our computer physically has.
Input devices and output devices like keyboard, monitors, mice, hard disk drives, speakers, Bluetooth, headsets, webcams, and network adapters.
These all devices are managed by the kernel by installing the driver of these devices. Suppose we have a Bluetooth device and we want to communicate with OS. But it is not possible to communicate without a Bluetooth driver. why?
Because this driver helps us to recognize and interact with the Bluetooth. Actually, the drivers speak to different types of hardware in computers and the hardware is also able to talk to each other and provide a way where we can connect the output devices and increase the functionality of the computer. In simple words, a driver is a small software that helps to extend the functionality of computers.
When we install the driver on the computer, the kernel starts the driver to communicate with the hardware. The kernel also helps to manage the data transfer.
The kernel has the ability to the intercommunication between these devices. It always provides the best and more efficient method to transfer the data in and out of the devices.
File Management
File management is a system of storing the files, naming the files, and handling the different files.
In a file, data is stored in binary form. Some data is in plain text. We can keep the documents, projects, and many more things. Data can be in different formats like audio, video, image, text, words, numbers, etc.
Each data files are of a different size and format. These take the space in memory according to size.
File System
File systems have different types and these are used for different purposes like Disk file systems, Tape file systems, Database file systems, or flash file systems. Each operating system has its own file system and is different from the others.
Windows operating system uses an NTFS file system. NTFS or New Technology File System was developed for the Windows NT version. Now it is also used. It has many features like encryption of the file, fast access to the file, security, and finding the files that are stored on a hard disk drive or solid-state drive. In 1993, NTFS was developed by Microsoft and IBM.
A file system is used to keep the files on a disk and how to keep track of the files stored inside the Disk. It helps to organize the files on disk.
In Linux OS, we use the ext4 file system. It is used only in Linux OS. Ext4 USB drive works on Linux OS but not in windows.
FAT 32 or File Allocation Table is the oldest file system. It is stored the files in chunks of 32 bits. Fat 32 does not support files greater than 4 gigabytes, and the size of the file system can not be greater than 32 gigabytes.
Data is stored on a hard disk in the form of data blocks. One large file is not stored in a single place on the hard disk. It breaks down the large file into chunks having a specific size and then stores it in different locations on the disk. This type of system to keep the data in disk improves the handling of the data faster and we can access the data quickly.
Disk Anatomy
Partition Tables
Partition is nothing but it shows the part of the Disks. You see on your computer a C: volume is available. In C volume, the Operating system is installed. This is a large volume of storage. So, you can divide it into two or more partitions. Actually, Partition is a division of a Solid State Drive or Hard Disk Drive that is divided virtually.
To see the partition in the computer go to 'Run' by pressing the shortcut 'windows + R' and type 'diskmgmt.msc' then click 'OK'.
You see this type of window that is given below.
In the above image, you can see how the volume is parted. There are three partitions shown in rectangular blocks.
Our Operating system uses two types of partition table
- MBR or Master Boot Record
- GPT or GUID Partition Table
Master Boot Records
Master Boot Records is the oldest partition. It is used in the windows. MBR has some programs to run the operating system. MBR disks use the BIOS partition table. The maximum size of the MBR partition is 2 terabytes. You can use drives that are 2 terabytes or less. But if you are using greater than 2 terabytes, it is wasted.
MBR has only 4 primary partitions on a disk. We can also extend this partition by using EXTENDED PARTITION. This is a type of partition that is split into 23 as addition partitions. Thus there are 26 partitions in the MBR disk.
GUID Partition Table
GUID Partition table is the new standard partition table. It is also used in windows. GPT disks use the UEFI partition table. The maximum size of the GPT partition is greater than 2 terabytes. It has one type of partition and it allows to do unlimited partitioning.
To check the partition in your operating system, which one is used for that Go to Disk management as you did before and click the right button on Disk 0 on the right side then go to the property and click there. A small window is opened and then goes to Volume. You can see the Partition style in Disk information.
You can see it like this.
Meta Data
Metadata is a type of bucket that contains the information of the files. It shows like
- Name of the file
- Size
- Identifier
- Location
- Date of creation
- Time of creation and so on
File Extension
A file extension is a type of identifier that shows the file type. It is joined as a suffix followed by a dot.
For example, .jpeg, .xlx, .ppt, .doc, .txt, .pdf, .json, .png, etc.
Actually, it shows the type of documents or which types of documents our files have.
Use space: Interaction with OS
To interact with OS, there are two way
- GUI
- CLI
GUI:- GUI or Graphical User Interface provides a user-friendly environment. You can easily use everything without knowing.
It helps to understand the function of the icon and also each icon has some name like Recycle Bin, This PC, Setting, etc.
so that users can read and use it confidently.
For example, If you are reading this blog, probably you are using GUI.
CLI:- CLI or Command Line Interface provides a command environment where you can type a command to see something like a folder,
files, process, services, etc. It interprets the text commands and then sends them to the Operating system for execution.
We can also use it to open the program. In windows OS we can use two CLI first CMD, and second Powershell. Powershell is a very powerful CLI. We can do everything in PowerShell. Command Line Interface is faster than Graphical User Interface. It responds quickly without any delay.
Logs
The log is a file that records every event on a computer. It has recorded some error, warning, or any operation that got failed.
Log files have the records of software runs, and messages between different users and computers. The process to keep the log file
is called logging.
To see the logs on the computer, follow the step:
Go to Control Panel ➡ System and Security ➡ Administrative tools ➡ Events Viewer
or
You can simply search in the taskbar search box 'Event Viewer'. A window is opened and there on the left side, you can see the windows log.
In the windows log, There are different types of logs.
- Application log
- Security log
- Setup log
- System log
- Forwarded Events
Boot Process
When a computer is started. it takes some moment to show you the login screen. The process is done within that moment is called Booting.
In simple words, Starting and Restarting the computer comes under the Booting Process. In this way, there are two types of Booting Process.
- Cold Booting
- Warm Booting
Cold Booting:- When you start your computer from the initial stage or your computer is turned off, the process that happens is called Cold Booting.
Warm Booting:- Your computer is not turned off and you restart the computer, that process is called Warm Booting.
The booting process initializes all hardware of the computer for use better.
Everything That Happens During The Booting Process
When you press the power button, the Booting process starts and follows the below step.
- The power is on and it shows on screen first.
- BIOS will be executed in ROM. It initializes the hardware of the computer.
- BIOS/UEFI runs a process called POST or Power On Self Test. It performs a diagnostic test to make sure the computer is working in a proper way. You notice to hear a beep time to time. If you hear a single beep, your computer is successfully booting. If you hear two beeps, your system has a POST error. How many times the computer is beeped is called the beep code. Beep codes indicate the computer troubleshoot the problem. Beep codes can be different for a different computer. Each manufacturer sets a different beep code in the computer.
- All the hardware is tested.
- BIOS loads the MBR or Master Boot Records to RAM.
- Master Boot Records will load the bootloader to RAM.
- The bootloader loads the operating system in RAM. It is a small program that executes and loads the OS. After loading the OS, the kernel is loaded. It controls access to computer sources.
- The kernel starts to load the drivers so that our hardware may talk to software and perform some tasks.
- Now, the essential process of the computer system and some items that are also essential for user space like login window, GUI is launched.
Virtual Machine: Copy of Real Machine: Virtual Box
A Virtual Machine is just like our actual machine. It has the same functionality that the actual machine has.
Virtual Machines can add multiple Operating systems like Windows, and Linux. In Linux OS, we can add like Ubuntu, CentOS, and Kali Linux and operate simultaneously.
It uses the physical resources of the computer. A virtual machine does not have its own CPU, Memory, or Storage. These are installed as application software and then we add Image files of other OS.
Actually, a virtual machine creates a virtual environment that provides us a platform where we can use another operating system. Suppose you are operating Windows OS, you can also operate the Linux OS in the same OS.
There is no need to install a separate Linux Operating System. Also, you can use other Windows OS in your installed Windows Operating System. These added virtual Operating Systems are deleted at any time from the virtual machine.
It doesn't affect our actual machine.
Linux in Windows
Ubuntu is open-source software. You can download the Disk image file from their websites.
How to add in Virtual Machine
To add in a Virtual Machine, First, we will download the virtual machine. Here we will download Virtual Box. It is the more popular virtual machine. To download, simply search on google Virtual Box and go to the website and download it.
After downloading create a Virtual disk image in the virtual box by clicking the New button.
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