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What Is DOS? An Introduction To The Disk Operating System

For some time, it has been widely acknowledged that DOS is insufficient for modern computer applications. Microsoft Windows helped alleviate some problems, but still, it sat on top of DOS and relied on it for many services. Even Windows 95 sat on top of it.

Newer operating systems, such as Windows NT and OS/2 Warp, do not rely on it to the same extent. Although they can execute DOS-based programs. It is expected that as these operating systems gain market share, DOS will eventually disappear.

In the meantime, Caldera, Inc. markets a version of DOS called DR-OpenDOSthat extends MS-DOS in significant ways. The initial versions of DOS were very simple and resembled another operating system called CP/M.

Subsequent versions have become increasingly sophisticated as they incorporated features of minicomputer operating systems. However, it’s still a 16-bit operating system and does not support multiple users or multitasking.

What is DOS?

A Disk Operating System (DOS) is any of the operating systems that run from the hard disk drive. This also refers to the specific family of the disk operating system which is also known as MS-DOS or Microsoft disk operating system.

Anything which commands and controls the computer’s hardware and its peripheral devices with control over the program and its functionality is known as the operating system. This operating system which runs through the hard disk is known as a disk operating system.

What is DOS?

Disk Operating System was the first operating system used by IBM-compatible computers. It was first available in two different versions that were typically the same.

But these were marketed and controlled under two different brands. MS-DOS was the framework behind Windows operating systems until Windows XP.

For the very first time, it was made and introduced for IBM by Microsoft which was known as IBM PC DOS in the year 1981.

List of DOS made from 1981 – 1998 are as follows :
  1. IBM PC DOS – 1981
  2. DR-DOS – 1988
  3. ROM-DOS – 1989
  4. PTS-DOS – 1993
  5. FREE-DOS – 1998

It was a rebranded version under the title IBM PC DOS, both of which came in the year 1981.

DOS other than Microsoft in the market are :
  1. Apple Disk Operating System
  2. Commodore Disk Operating System
  3. Apple Pro Disk Operating System
  4. Atari Disk Operating System
  5. TRS Disk Operating System
  6. Amiga Disk Operating System

“PC-DOS” was the version of the dos developed by IBM and sold to the first IBM-compatible manufactured computers. “MS-DOS” was the version of dos that Microsoft bought the rights and patents, and was merged with the first versions of Windows.

Command-line was used by DOS, or text-based interface, that typed command allowed by the users. By giving simple instructions such as PWD (print working directory) and cd(change directory), the user can open files or run the program or browse the files on the hard drive.

Written originally by Tim Patterson (considered as the father of DOS) and owned by Seattle Computer Products, Microsoft takes over  86-DOS for $75,000. Microsoft licensed the same software and released it with an IBM PC as MS-DOS 1.0 in 1982 with IBM and Microsoft joint venture.

Are there Commands used?

Of course, Yes. The Disk Operating System works on the phenomenon of operating functions through commands. Here we have 8 types of commands:

  1. Assoc: Associated Extension
  2. Tree: View Directory Structure
  3. File Search & Comparison
  4. Network Commands
  5. Windows Utilities
  6. AT Commands
  7. Comparison
  8. Command Prompt

To explain it more I can give you some examples of commands under its command prompt which are inclusive of; Append, Arp, Assign, Batch, Defrag, Edlin, and many more.

Which are the Features of DOS?

Below are some of the distinguishing features which you should clearly know:

  • First, it’s a 16-bit operating system, and the maximum space available is 2 GB.
  • Secondly, the mouse cannot be used to operate it like input in it is through basic system commands.
  • Secondly, it’s a free OS that uses a text-based interface and requires text and codes to operate.
  • It is a single-user operating system and it does not support graphical interface.
  • Lastly, it’s a Character-Based interface system that is very helpful in making file management. Such as creating, editing, deleting files, etc.

What are its Advantages & Disadvantages?

Now you must have been cleared on how to work with DOS. And with this in mind, it’s very important for us to know the advantages and disadvantages of using it.

So the following are the advantages :

  • We have direct access to the BIOS and its underlying hardware.
  • Due to its size, it will “boot” much faster than any windows version, thus it will run in a smaller system.
  • It is very lightweight so it does not have the overhead of the multitasking operating system.
  • It is good for making workarounds for managing/administering an MS system, and for combining programs.

With the advantages, it has many disadvantages too which are listed below:

  • No multitasking supported by the OS.
  • Difficulty in memory access when addressing more than 640MB of RAM.
  • Interrupt levels for hardware needs to be managed by our self.
  • Automatic IRQ ordering is not supported by the OS.

What are the Required Skills?

Though it’s barely an operating system it has a vast functionality and OS to work with. It works on the phenomenon of doing less and getting more.

At the same time, it opens up a large window into the glorious past of IBM PC compatibles. Required skills with essential prerequisite knowledge are as follows. Whereby, as a user, you must be able to:

  • Create assemblies
  • Debug and test small .com files
  • Patch .exe and .com files
  • Work with 80*86 assemblies
  • Relate and work on instruction such as MOV, ADD, INT, DB, JMP, LOOP, etc.
  • Manipulate and work with notable imitators include DR-DOS, OpenDNS, and FreeDOS

There are many websites where you can download hundreds of old, archived, DOS programs.

It really has its much importance as it was an enabler for you to develop ad-hoc batch (*.bat) files. Or even programs to that tasks could be automated.

Command Line Interface also allowed you to use commands with switches to interact with the PC resources. It also allows us to use undocumented APIs such as :


It’s important to realize, upgrading your PC from Windows 7 to Windows 10 has a number of benefits. For a start, because both operating systems are made by Microsoft the upgrade process is relatively easy. And in many cases, you can keep your files on your PC.

With the introduction of Windows 3.0, it was near to its extinction with the Gui severely demolishing the use of Ms. DOS. With the introduction of Windows 95, it was used for bootstrapping, troubleshooting, and backward-compatibility with its old software. Particularly games, and no longer released as a standalone product.

And so, this was the whole overview of Ms. DOS. In the end, I would like to say that it has a vide element of exposure so it can never be outdated. Therefore, people working on it will always be profitable as it is free and it has the whole feature. As compared to the paid version of any operating systems such as IOS, Windows 10, etc.

Apart from that, it’s a licensed OS from Microsoft so we can trust it as it is one of the biggest software companies. Below are more related topic links that you might find resourceful;

  1. What is the CPU?
  2. Windows 10 | Why is it the Best Alternative to Windows 7?
  3. Software-as-a-Service | What is the Meaning of SaaS?
  4. Operating System | What Is It & Which are the main types?
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