What is DOS(Disk Operating System)? Definition, Features, and Work

As a modern computer user, it's hard to imagine a time without flashy graphics and intuitive interfaces, but that's how it used to be. Back then, DOS or the Disk Operating System, reigned supreme, setting up the roots for a revolution in personal computing. With DOS, all you need are straightforward text commands to bring a computer to life. Wondering What is DOS, and how its powerful simplicity can make tasks such as file management and program execution possible? 

In this blog, we will explore What is DOS and learn what made it such an enduring component of computing history. So read on and uncover the DOS features that paved the way for today's tech marvels! 

Table of Contents

1) What is a DOS (Disk Operating System)?  

2) Current Uses of DOS 

3) Commonly Used DOS Commands  

4) Benefits of DOS  

5) Drawbacks of DOS  

6) Conclusion 

What is a DOS (Disk Operating System)? 

A DOS, short for disk Operating System, is an OS that runs from a disk drive. The term can also mean a particular family of disk Operating Systems, most commonly MS-DOS, which is an acronym for Microsoft DOS. An OS controls a computer's hardware and peripheral devices while allowing other software programs to function. 

Early computers of the 1940s and 1950s didn't have disk drives and were instead hard-wired to carry out specific computations. Later, computers were equipped to store instructions loaded into their memory using punch cards and magnetic tapes. While computer memory space was limited, it was considered cutting-edge technology when the instructions to control a computer were moved into a disk drive, such as an internal HDD or floppy disk.
 

Features of DOS 

Here are some of the distinguishing features of DOS: 

a) It's a free, 16-bit Operating System. 

b) The mouse can't be used to operate it. Input happens through basic system commands. 

c) The maximum space available is 2 GB. 

d) It uses a text-based interface and needs text and codes to operate. 

e) It's a single-user OS and doesn't support a graphical interface. 

f) It is a character-based interface system. 

g) It helps with file management, e.g., editing, creating, deleting files, etc. 

How Does DOS Work? 

Here’s a basic breakdown of how DOS commands work: 

a) Boot Process: DOS undergoes a boot process when the computer turns on. The BIOS (a DOS component) initially checks if the device works properly. 

b) DOS Kernel: After the BIOS conducts a self-check, the DOS Kernel takes control. This is when the computer's true operation begins. The kernel also manages operating files, memory, etc. 

c) Command Prompt: Once the kernel takes over, it’s time for the user to enter commands. Command prompts are the instructions you want the computer to perform. 

d) Command Execution: Command execution happens as the kernel reads and interprets commands into actions. 

e) File System: Under DOS, the computer stores the data in directories (now known as files). 

f) Running Applications: Apps boast their own set of commands built into them. When a user prompts the computer to run an app, the app temporarily takes over. 

g) Exiting DOS: After performing the task, when the user shuts the computer down, DOS automatically shifts into BIOS mode. 

The cycle repeats until the computer starts up again, continuing the above-mentioned process. 

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Current Uses of DOS  

Windows may have replaced DOS, but some people still go for the DOS option. If you want to know the reason for this, here are some ways that industries use disk Operating Systems today: 

1) Legacy Systems 

Some early applications and programs developed by governments, companies, and organisations were designed for DOS-based computers. Restructuring these systems needs time and money. This structure prompted organisations to opt for DOS and hire specialised support and maintenance engineers. 

2) Embedded Systems  

Due to its simplicity, DOS is still used in some embedded systems (e.g., medical equipment, public space kiosks, ATMs, and store point-of-sale terminals). Updating embedded systems for a modern OS is an expensive endeavour. 

3) Vintage Computing and Retro Gaming  

Hobbyists and collectors have preserved their DOS computers from decades ago. To run classic software on updated computers, virtual machines and DOS emulators are dedicated to the community of nostalgics and retro gamers.
 

4) Nostalgia and Learning  

Understanding how pre-GUI computers (GUI stands for Graphical User Interface) work is the first step to learning about Programming. DOS accomplishes this by exposing tech students and enthusiasts to the early days of computing. They can easily experiment with DOS with low-level Programming before moving up to today’s more complex Operating Systems. 

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Commonly Used DOS Commands  

It's important to note that MS-DOS is not case-sensitive so that commands can be typed in either uppercase or lowercase. The following table summarises some of the most used DOS commands: 

Benefits of DOS  

Here are some advantages of DOS to consider: 

1) You can have direct access to BIOS and its underlying hardware. 

2) Its size will boot faster than any Windows version, making it capable of running on a smaller system. 

3) It's very lightweight, so it doesn't have the overhead of the multitasking Operating System. 

4) It is suitable for making workarounds for managing or administering an MS system and combining programs. 

Here’s an example of creating a directory and a file in DOS: 

Step 1: Use the mkdir command to create a new directory. 

Command:
 

Example Usage:
 

A directory named Projects is created in the current directory. 

Step 2: Use the echo command to create a file with some text content. 

Command:
 

Example Usage:
 

Result: 

A file named ProjectNotes.txt is created in the Projects directory with the text:
 

Drawbacks of DOS  

Despite its advantages, it has many drawbacks too, which are listed below: 

1)  The OS doesn't support multi-tasking. 

2) You'll face difficulty accessing memory when addressing more than 640 MB of RAM. 

3)  You will have to manage interrupt levels for the hardware. 

4) The OS doesn't support automatic IRQ ordering. 

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Conclusion 

In conclusion, DOS belongs to the early days of computing, but its legacy as the foundation of modern Operating Systems live on. Its simplicity and command-line structure made it an essential tool for file management and system control in the early computers. Understanding What is DOS offers valuable insights into the ingenuity behind today’s sophisticated GUI-heavy Operating Systems. 

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