Before Windows, there was MS-DOS. It’s a somewhat-meaningless name these days that you may have seen on old PCs, old software, or browsing sites like this. But what is MS-DOS? Why did old computers have it, and what happened to it when Windows came along?
And does anyone still use MS-DOS?
What Is MS-DOS?
An acronym of Microsoft Disk Operating System, MS-DOS is also known as Microsoft DOS. A DOS is a “disk operating system” which is basically a collection of tools and commands for running software from disk (a hard disk drive or floppy drive) and managing the device (e.g. formatting).
Additionally, DOS commands would let you install and then run software. Typically, this would be spreadsheets and word processors; sometimes, it would be games or art packages.
These days, all of this is wrapped up on Windows or whatever operating system you use, complete with its mouse-driven graphical user interface (GUI). When the PC first arrived, however, the DOS—a command line interface—was how you interacted with the device.
But if you loaded up a PC running MS-DOS now, you'd notice two key differences:
- Only one application can run (there is none of the multitasking we've become used to)
- There is no support for user accounts
MS-DOS was introduced in 1981, with its final release on Windows Me in 2000. With the arrival of Windows 95, MS-DOS was shunted to the sidelines as a secondary mode for legacy software to run. By the time of Windows XP, MS-DOS was almost absent, with only poor DOS emulation and an emergency boot disk that relied on it. As of Windows 10, there is no requirement for an MS-DOS boot disk.
Computers no longer ship with floppy drives!
Before Windows: PC-DOS, and MS-DOS
When IBM developed the first personal computer, it needed a disk operating system. For this, it turned to Microsoft to develop PC-DOS.
Many old PCs would boot with the phrase PC-DOS displayed on the POST screen. But over time, this changed, because IBM stopped being the only producer of PCs.
Columbia Data Products was able to reverse engineer the PC’s BIOS, and Compaq followed soon after. Once this happened, any manufacturer could develop its own BIOS. Taking advantage of this, Microsoft released MS-DOS to IBM’s competitors in the PC market.
So, PC-DOS and MS-DOS were both produced by Microsoft. As IBM’s share of the PC market—which it essentially created—shrank, so did use of PC-DOS.
MS-DOS and Windows
MS-DOS gave Microsoft a foothold in the early PC industry. While it had produced disk operating systems for MSX and Commodore, it identified the business computing industry as a target that was set to grow.
Microsoft had already released its office tools for MS-DOS, and in 1987 issued Windows 1.0. The first version of Windows brought a GUI environment to the PC, something that had been available on Apple and Amiga computers several years by this time.
As Windows grew with each version, usage of MS-DOS declined. When Windows 95 came along—spurred by the inclusion of a web browser—it was the beginning of the end for MS-DOS. No longer did the PC boot into MS-DOS; instead, it booted into Windows.
Windows 95 and 98 maintained an MS-DOS mode that could be switched to from the GUI. This accommodated legacy software as well as contemporary titles, many of which were released without Windows support.
What Is an Emergency Boot Disk?
Installing Windows 95 required a boot disk plus the installation media (13 3.5-inch floppy disks in total, but it was also shipped on CD-ROM). In the event of a fault with the operating system, Windows could be reinstalled with the help of the boot disk.
Windows 95 and later (all the way to Windows 8.1) could create an emergency boot disk. This included core MS-DOS files which facilitated re-installation of Windows.
To be brief, you would insert the boot disk into the computer, which would then enable initiation of the operating system’s installation. So, as long as you had the installation media, Windows could be reinstalled.
Until Windows XP, the operating system relied on the boot disk for installation. While emergency boot disks could be created for system recovery purposes, from Windows XP onwards only the installation media was required.
How the Command Prompt Replaced the MS-DOS Prompt
You may be familiar with the Windows Command Prompt. This is a black box for command line interfacing with a Windows PC or laptop. (You can open it by pressing WIN+R and then entering cmd and clicking OK.)
It owes its appearance to the latter days of MS-DOS; Windows 95 and 98 could switch into MS-DOS mode, or access it via what became the Command Prompt.
Back then, it was known as the MS-DOS prompt—you may work with someone who still refers to it this way.
Eventually, as MS-DOS legacy support was finally stripped from Windows, so the Command Prompt became prominent. In turn, this has been superseded by Windows PowerShell.
You Can Emulate MS-DOS With DOSBox
With all this talk of MS-DOS, you might be wondering if there is a way you can still use it.
Well, you don’t need an old computer to experience MS-DOS.
Since 2002, emulation of the MS-DOS environment has been possible with DOSBox. It’s possible to run old software on a modern PC (i.e. MS-DOS titles released between 1981 and 2001) with DOSBox.
While the DOSBox project was initially aimed at running all DOS software, it is mostly used for gaming. Our guide to playing retro games on DOSBox will show you how to do this.
MS-DOS Is Now Open Source and on GitHub
Recognizing the importance of MS-DOS, Microsoft eventually released versions 1.25 and 2.0 on GitHub, specifically “for reference purposes.” It is listed as having adopted the Microsoft Open Source Code of Conduct. This is an important development as Microsoft historically a closed source exponent.
Permission is given to fork and experiment with MS-DOS, although note that this is an early version. The last release of MS-DOS was 8.0 on Windows Me.
So, what if you wanted to download MS-DOS and install it on an old computer?
Need an OS for an Old PC? Try FreeDOS
Say you have an old PC from the 1990s, and want to get it up and running. Trying to run current software would be pointless, as things have changed. However, there is 20 years’ worth of software that will run on this machine.
But there is a problem: an unbootable HDD means you need to reinstall the operating system. As the open source version of MS-DOS isn’t particularly useful for software made after 1990, you’ll need an alternative.
That’s where FreeDOS comes in. Distributed under the GNU General Public License, FreeDOS is open source software. If your old PC or laptop has a CD-ROM drive, FreeDOS can be installed. There is also the option to us a boot disk if necessary. For more modern systems, FreeDOS can be installed from a USB drive.
FreeDOS can also be downloaded to a PC and run in a virtual machine. It runs just like MS-DOS, as it is essentially a replacement for it. As you can see in the video, you can even write programs in FreeDOS.
Download: FreeDOS (free)
MS-DOS: a Relic of the Early PC Era That Remains Usable
It is incredible that software developed over 40 years ago continues to have influence. Without MS-DOS, the PC would not have taken off; there would be no Microsoft Windows.
That we can still use MS-DOS—either using the open source release, DOSBox, or FreeDOS—is a gift. So many great applications and games can be revisited on systems running MS-DOS and its variants. While you might be able to buy them from GOG.com and install on a modern PC (thanks to DOSBox technology) the option remains for a Microsoft DOS-based PC to be used instead.