What is Operating System? Explain Types of OS, Features and Examples

 

What is an Operating System?

An Operating System (OS) is a software that acts as an interface between computer hardware components and the user. Every computer system must have at least one operating system to run other programs. Applications like Browsers, MS Office, Notepad Games, etc., need some environment to run and perform its tasks.

The OS helps you to communicate with the computer without knowing how to speak the computer’s language. It is not possible for the user to use any computer or mobile device without having an operating system.

History Of OS

• Operating systems were first developed in the late 1950s to manage tape storage
• The General Motors Research Lab implemented the first OS in the early 1950s for their IBM 701
• In the mid-1960s, operating systems started to use disks
• In the late 1960s, the first version of the Unix OS was developed
• The first OS built by Microsoft was DOS. It was built in 1981 by purchasing the 86-DOS software from a Seattle company
• The present-day popular OS Windows first came to existence in 1985 when a GUI was created and paired with MS-DOS.

Following are the Operating System examples with the latest Market Share

OS Name	Share
Windows	40.34
Android	37.95
iOS	15.44
Mac OS	4.34
Linux	0.95
Chrome OS	0.14
Types of Operating System (OS) Following are the popular types of OS (Operating System): Batch Operating System Multitasking/Time Sharing OS Multiprocessing OS Real Time OS Distributed OS Network OS Mobile OS Batch Operating System Some computer processes are very lengthy and time-consuming. To speed the same process, a job with a similar type of needs are batched together and run as a group. The user of a batch operating system never directly interacts with the computer. In this type of OS, every user prepares his or her job on an offline device like a punch card and submit it to the computer operator. Multi-Tasking/Time-sharing Operating systems Time-sharing operating system enables people located at a different terminal(shell) to use a single computer system at the same time. The processor time (CPU) which is shared among multiple users is termed as time sharing. Real time OS A real time operating system time interval to process and respond to inputs is very small. Examples: Military Software Systems, Space Software Systems are the Real time OS example. Distributed Operating System Distributed systems use many processors located in different machines to provide very fast computation to its users. Network Operating System Network Operating System runs on a server. It provides the capability to serve to manage data, user, groups, security, application, and other networking functions. Mobile OS Mobile operating systems are those OS which is especially that are designed to power smartphones, tablets, and wearables devices.

Networking Basics

 

Basic of Network

A network is a group of two or more devices that are connected to each other to share the data or share the resource. A network contains a number of different computer system that is connected by a physical or wireless connection like server or router. This router has direct access to the internet. The device can only connect to the internet through the router or access point.

For example: Suppose the client or device connected to the network through Wi-Fi or Ethernet. If the client opens the browser and types google.com, then your computer will send a request to the router for asking google.com. The router will go to the internet and request google.com. The router will receive google.com and forward that response to the computer. Now the client can see google.com on the browser as a result.

In networking, devices on the same network communicate with each other using packets. If you send a video, login a website, sending chat messages, sending email, all the data is send as packets. In networking, devices ensure that these packets go in the right direction using the mac address. Each packet has the source mac and destination mac, and it flows from the source mac to destination mac.

Pre-connection Attack

Pre-connection attack is the first part of the network penetration testing. To perform this attack, we will look at the fundamentals like how to show all the networks around us, how to find the details of all the connected devices to a particular network. Once we know about the network and connected devices to it, we can disconnect any device without knowing the password of that device.

Following are the basic steps we will be going through to perform Pre-connection attack:

1. Wireless Interface in Monitor mode: In this step, we will change the mode of wireless device as Monitor mode.
2. About airodump-ng: In this step, we will use airodump-ng to list all the network around us and display useful information about them.
3. Run airodump-ng: In this step, we will see all the devices that are connected to a particular network and collect more information about it.
4. Deauthenticate the Wireless client: In this step, we can disconnect any device which is shown in the previous step using the aireplay-ng.