time to read 4 min read
What is DOS_

What is DOS?

Have you ever wondered how your computer knows what to do? The answer lies in the operating system, or OS. One of the oldest and most influential operating systems is DOS, or Disk Operating System. DOS is like a command center that tells the computer what to do and how to do it. 

Unlike modern operating systems, DOS uses text-based commands instead of graphical user interfaces. While it may seem simple and primitive, DOS is also fast, powerful, and flexible. However, it also has its drawbacks, such as its complexity and obsolescence. In this article, we will explore the fascinating world of DOS.

Historical background

DOS was born in the late 1970s and early 1980s, when personal computers were becoming more popular and affordable. At that time, there was no standard operating system for PCs, and different manufacturers and developers used different systems, such as CP/M, UCSD Pascal, and Apple DOS. 

However, in 1980, IBM, the leading company in the PC market, decided to create its own operating system for its new line of computers, the IBM PC. IBM approached Microsoft, a small software company founded by Bill Gates and Paul Allen, and asked them to provide an operating system for their PC. Microsoft agreed, but they did not have an operating system of their own. Instead, they bought an existing system called QDOS, or Quick and Dirty Operating System, from another company called Seattle Computer Products, and modified it to suit IBM’s specifications. They renamed it MS-DOS, or Microsoft Disk Operating System, and licensed it to IBM. IBM also renamed it PC-DOS, or Personal Computer Disk Operating System, and sold it with their PCs.

  • The original name of QDOS was 86-DOS because it was designed for the Intel 8086 processor.
  • The first version of MS-DOS was released in 1981, and the last version was released in 1994.
  • The most popular and widely used version of MS-DOS was version 6.22, which was released in 1994.
  • The name DOS is pronounced as “doss”, not “dee-oh-ess”.

DOS vs modern Windows OS

DOS and Windows are both operating systems developed by Microsoft, but they have different designs and functionalities. Windows is a graphical operating system that uses a graphical user interface (GUI) to interact with the user and the computer. 

DOS, on the other hand, is a text-based operating system that uses a command-line interface (CLI) to interact with the user and the computer. The CLI is a black screen with a blinking cursor where you can type commands and see the results. The CLI is less user-friendly and more complex than the GUI, and it requires the user to memorize and type the commands and their arguments. 

Some of the similarities between DOS and a modern Windows OS are:

  • They both use the same drive letters and paths to identify and locate the files and folders on the disk, such as C:\, D:\, etc.
  • They both use the same file extensions to indicate the type and format of the files, such as .doc, .exe, .bat, etc.
  • They both can run some of the same programs and applications, such as the command prompt, the notepad, the calculator, etc.

Some of the differences between DOS and a modern Windows OS are:

  • Windows has a graphical and user-friendly interface, while DOS has a text-based and complex interface.
  • Windows supports multitasking, while DOS supports only single-tasking.
  • Windows has a built-in and advanced file system, while DOS relies on an external and primitive file system.
  • Windows has a built-in and comprehensive network and internet support, while DOS has a limited and rudimentary network and internet support.

Common DOS commands: how does it work? 

DOS has not completely disappeared, even though Windows has replaced it as the main operating system for most PCs. If you open the Command Prompt application on a Windows machine, you’ll see a command line that looks similar to the old DOS prompts. This is because Windows still supports some of the DOS commands and programs for compatibility and convenience purposes. 

However, the Command Prompt is not the same as DOS. It is actually a Windows program that emulates some of the DOS functionality, Also, the Command Prompt is not the only way to access the command line on Windows. There are other tools, such as PowerShell and Windows Subsystem for Linux, that offer more advanced and flexible features for command line users.

DIRDisplays a list of files and subdirectories in a directory
CDChanges the current directory
MDCreates a new directory
RDRemoves a directory
COPYCopies one or more files to another location
DELDeletes one or more files
TYPEDisplays the contents of a file
RENRenames a file or directory
ATTRIBChanges the attributes of a file or directory
XCOPYCopies files and directories, including subdirectories


In conclusion, DOS is an important part of the history of personal computing, as it was the first operating system used by IBM-compatible PCs. While it has been largely replaced by Windows and other command line tools, it has not completely disappeared. The Command Prompt application on Windows machines still supports some of the DOS commands and programs for compatibility and convenience purposes. However, it is important to note that the Command Prompt is not the same as DOS, as it has some differences and limitations.

Knowing about DOS and its commands can be useful for troubleshooting problems, managing files, and accessing network resources. It can also give you a deeper understanding of how operating systems and command line interfaces work. If you are interested in learning more about DOS and its commands, I encourage you to try it out for yourself and explore the various resources available online. Whether you are a beginner or an experienced user, there is always something new to learn and discover about DOS and its legacy.