Evolution Of Operating Systems

Mohit Lalwani
7 min readJun 3, 2022
Various versions of OS until date

The First Generation (1940 to early 1950s)

When the first electronic computer was developed in 1940, it was created without any operating system. In early times, users have full access to the computer machine and write a program for each task in absolute machine language. The programmer can perform and solve only simple mathematical calculations during the computer generation, and this calculation does not require an operating system.

The Second Generation (1955–1965)

The first operating system (OS) was created in the early 1950s and was known as GMOS. General Motors has developed OS for the IBM computer. The second-generation operating system was based on a single stream batch processing system because it collects all similar jobs in groups or batches and then submits the jobs to the operating system using a punch card to complete all jobs in a machine. At each completion of jobs (either normally or abnormally), control transfer to the operating system that is cleaned after completing one job and then continues to read and initiates the next job in a punch card. After that, new machines were called mainframes, which were very big and used by professional operators.

The Third Generation (1965–1980)

During the late 1960s, operating system designers were very capable of developing a new operating system that could simultaneously perform multiple tasks in a single computer program called multiprogramming. The introduction of multiprogramming plays a very important role in developing operating systems that allow a CPU to be busy every time by performing different tasks on a computer at the same time. During the third generation, there was a new development of minicomputer’s phenomenal growth starting in 1961 with the DEC PDP-1. These PDP’s leads to the creation of personal computers in the fourth generation.

The Fourth Generation (1980 — Present Day)

The fourth generation of operating systems is related to the development of the personal computer. However, the personal computer is very similar to the minicomputers that were developed in the third generation. The cost of a personal computer was very high at that time; there were small fractions of minicomputers costs. A major factor related to creating personal computers was the birth of Microsoft and the Windows operating system. Microsoft created the first window operating system in 1975. After introducing the Microsoft Windows OS, Bill Gates and Paul Allen had the vision to take personal computers to the next level. Therefore, they introduced the MS-DOS in 1981; however, it was very difficult for the person to understand its cryptic commands. Today, Windows has become the most popular and most commonly used operating system technology. And then, Windows released various operating systems such as Windows 95, Windows 98, Windows XP and the latest operating system, Windows 7. Currently, most Windows users use the Windows 10 operating system. Besides the Windows operating system, Apple is another popular operating system built in the 1980s, and this operating system was developed by Steve Jobs, a co-founder of Apple. They named the operating system Macintosh OS or Mac OS.

What is a disk operating system?

A DOS, or disk operating system, is an operating system that runs from a disk drive. The term can also refer to a particular family of disk operating systems, most commonly MS-DOS, an acronym for Microsoft DOS.

An operating system (OS) is the software that controls a computer’s hardware and peripheral devices and allows other software programs to function. Early computers of the 1940s and 1950s did not have disk drives. Instead, they were hard-wired to carry out specific computations.

Later, computers were able to store instructions loaded into the computer’s memory using punch cards and then, after that, magnetic tapes. Computer memory space was limited, and when the instructions to control a computer were moved onto a disk drive, such as a floppy disk or internal HDD, it was considered cutting-edge technology.

DOS is also used to describe several similar command-line disk operating systems. Early computers, such as the Commodore 64, Atari 800 and Apple II, all featured a disk operating system, including Commodore Business Machines DOS, Atari DOS and Apple DOS, respectively. DOS/360 was an OS for IBM mainframes, which first appeared in 1966, but it is unrelated to the 8086-based DOS of the 1980s.


  • Efficient file management — DOS helps in efficient file management. The file operations such as creation, editing and deletion of files is easy.
  • Correct environment — It provides the user an environment where user can do input, output and give commands on the command line efficiently.
  • Single user operating system — It can have only one user at a time on the the computer.
  • Space — It has a maximum space of 2 GB.
  • Specification — It is a 16 bit operating system.

How does a disk operating system work?

When a computer is powered on it goes through various steps called the boot process. For a computer running a disk operating system, the following six steps are standard:

  1. The read-only memory (ROM) bootstrap loader reads the Master Boot Record and passes control over to it.
  2. The boot record loads the disk operating system into memory, and it takes control of the machine.
  3. The computer transfers data stored on a magnetic disk to its main memory, the random access memory.
  4. It also transfers data to external devices attached to the computer, such as a computer screen or printer.
  5. The computer provides various application programming interfaces for programs like character input/output (I/O), memory management, program loading and termination, as well as handling input from the user through a keyboard.
  6. The OS also provides file management that organizes, reads and writes files on storage. The files are organized in a hierarchical structure of directories, subdirectories and files.

A disk operating system doesn’t have a graphical user interface (GUI). Its interface is character-based, so users must type commands in the command line to indicate what actions they want.

Common DOS commands

MS-DOS is not case-sensitive, so commands can be typed in either uppercase or lowercase. However, other disk operating systems have case-sensitive CLIs. DOS commands include the following.

  1. cd - Changes directory - Type cd c:\techtarget in the command line to change the working directory to c:\techtarget.
  2. cls - Clears all the contents on the screen, leaving only the command prompt - Type cls in the command line.
  3. copy - Copies one or more files to another location - Type copy c:\techtarget\file.txt c:\techtarget\file2.txt to copy c:\techtarget\file.txt to c:\techtarget\file2.txt.
  4. del - Deletes one or more files - Type del c:\techtarget\file2.txt to delete the file file.txt from the directory c:\techtarget.
  5. deltree - Deletes all files and subdirectories from a computer - Type deltree c:\techtarget\drafts to delete the directory drafts, including all files and subdirectories contained in it.
  6. dir - Displays a list of files and directories in a directory - Type dir c:\techtarget to display a list of files and directories in the directory c:\techtarget.
  7. format - Formats a disk for DOS files - Type format e: to format the disk in drive e: for use with DOS.

Advantages And Disadvantages Disk Operating System


1. Direct access to BIOS

One of the best things about this operating system is that it provides direct control over the computer’s Basic Input/output System (BIOS). This allows you to operate any underlying hardware.

2. Boots faster

This OS is exceptionally lightweight. As such, it boots faster than any other operating system. It expectantly runs on a smaller system, though.

3. Managing/Administering MS

DOS is a capable operating system for implementing workarounds when managing or administering a Microsoft operating system. This is largely due to its ability to more directly control over computer processes than a GUI-based system.


1. Single task limitation

A crucial difference from present-day operating systems is that it doesn’t support multitasking on your computer. If you’re accustomed to working on several open windows or tabs, you won’t have a similar experience with DOS. Instead, you are limited to one task at a time.

2. Character User Interface

Because it relies on CUI commands, it cannot open pictures, videos, games, and most other things that modern OSs can. This also means mouse inputs are not supported. The only way to control this computer system is by typing DOS operating system commands.

3. Single-user

Only one user can operate this operating system. In other words, whoever uses the machine has access to the data stored in it.

Funny enough, older computers often had physical padlocks to prevent others from accessing them.

4. Can’t address more than 640 MB of RAM

Considering when DOS was initially released, it’s understandable that it doesn’t have the capacity of modern-day operating systems. As such, expect issues if addressing more than 640 MB of RAM.

DOS Vs Windows

DOS Vs Linux


There’s no doubt that the disk operating system, better known as DOS, has played a significant role in the development of personal computing. And while used only occasionally these days, it hasn’t been completely forgotten.

It’s a perfect example of how much operating systems have evolved during these past decades. We can only wait and see what the future holds for Windows and other popular OS options.

Authors: Aditya Wanjari, Mohit Lalwani, Nitesh sonawane , Anushka Wankhade, Shresthi Yadav


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  2. https://www.ionos.com/digitalguide/server/know-how/dos-what-is-a-disk-operating-system/
  3. https://techjury.net/blog/what-is-dos/#gref
  4. https://www.educba.com/what-is-dos/
  5. https://www.techtarget.com/searchsecurity/definition/DOS