While the main computer operating systems are multi-user, multitasking systems with virtual memory, you may long for the days when a user was in full control of a PC.

If you are missing out on the days of the 640K limit and figuring out which drivers to load into high memory, FreeDOS might be for you. This open source reimplementation of MS-DOS has some serious uses.

What is FreeDOS?

As the name suggests, FreeDOS is an open source implementation of Microsoft's MS-DOS. It aims at a high degree of compatibility with classic DOS hardware and software and adds some additional functions such as extensive online documentation.

Since it is designed as a DOS replacement, it currently only runs on Intel chips. The project recommends a 386 chip or better, at least two megabytes of RAM, and at least 40 MB of hard disk space. Most modern PCs should exceed these requirements, to say the least.

FreeDOS has a built-in network so you can even take it online. Also, don't think that you are limited to just text-based programs. FreeDOS offers desktop options like OpenGEM and oZone.

A brief history of FreeDOS

Jim Hall started the FreeDOS project as a student at the University of Wisconsin-River Falls in 1994. Windows 94 was on the horizon and it was clear that Microsoft would invest in this platform instead of MS-DOS.

"DOS seems to be a popular system, and there is already a lot of hardware available ready to support it," Hall wrote in 1998. "Microsoft won't develop DOS forever, and you can't rely on commercial programming companies like IBM or Digital to continue DOS. I think it will then be up to those on the Internet to develop their own DOS (hereafter Free-DOS) and I believe there is a lot of support for this type of project. "

The first version of the system appeared in the same year. Although the project is not as well known as other open source operating systems, FreeDOS has some visibility. When Dell first introduced computers with open source operating systems, for some reason they decided to preinstall FreeDOS on computers instead of more comprehensive systems like Ubuntu.

What can you do with FreeDOS?

Although you can download a free, open source implementation of DOS, why bother if you already have a multitasking operating system in protected mode with virtual memory on your computer?

There are several reasons.

Update the BIOS

As more and more computer manufacturers offer tools to automate the PC BIOS update, there may be times when you need to manually update or reflash it. Many motherboards only boot MS-DOS or similar systems.

You can do this by downloading the BIOS file and copying it to a USB stick or other bootable media with FreeDOS installed. Then start the computer with the stick inserted and run the command to install the new BIOS. This varies depending on the computer or motherboard manufacturer.

Related: The BIOS explains: boot order, video memory, resets and optimal default settings

Play old DOS games

While it is possible to download DOS games and play them in an emulator like DOSBox, if you still have old PC hardware, playing games on a beige box from the 90s can be especially fun. FreeDOS comes with the drivers to support sound cards, graphics cards, and mice. If you just want to play games and don't have old PC hardware, DOSBox is a great alternative.

FreeDOS even includes some games on the installation CD image, including Boom, the free Doom clone pictured above. The system installs these games in the C: GAMES Directory through the package manager, if you want to install them. If you have floppy disks or CDs with DOS games, you can install and run them from a hard drive or on a virtual machine as you did before.

Using legacy DOS applications

FreeDOS has another important practical use: accessing files from older DOS applications. Perhaps you need financial records from an old Lotus 1-2-3 or VisiCalc spreadsheet from the 80s.

All you have to do is connect a floppy disk drive to the computer and start FreeDOS or transfer the floppy disk to a virtual machine. You can use a copy of the program to get the file and export the data in a format usable on modern computers.

Explore the system

Linux is also free and open source, but it is also very complex. If you ever look at the source code of the kernel alone, it can be very difficult to understand, even for people with experience in C and systems programming.

DOS is much easier as single-tasking and single-user. For these reasons, if you want to study operating systems in detail, FreeDOS is a good place to start.

Embedded systems typically have more limited processors and memory. Simple systems like MS-DOS are widely used in this area. While many embedded developers are moving to full-featured systems like Linux on Raspberry Pi, there is still a lot of development going on in this area. FreeDOS has the advantage over MS-DOS that it is open source and is actively being further developed.

How to install FreeDOS

The installation of FreeDOS is similar to the installation of other operating systems. You simply download the ISO file, extract it to suitable media, boot the system and run the installer.

Download: FreeDOS

You should try installing and running FreeDOS in a virtual machine like VirtualBox before committing to the actual hardware. If you get an "invalid opcode" error message when trying to install FreeDOS in VirtualBox, don't panic. There is a little workaround. In the menu, Install on hard drive should be selected automatically. Beat tab and then add "raw" to the command line.

Installation is actually easy. Follow the instructions and restart the newly installed system.

The default boot menu option loads a memory manager that frees memory by loading drivers beyond the initial 640K on the original PC. This is why you should use it unless you are having trouble booting. The boot menu provides a type of "safe mode" that does not load memory management programs and runs in "real mode".

You can then use the FDIMPLES command to install packages from the installation CD, including network applications. You must have the CD inserted in order to install new packages.

Go online at FreeDOS

While networking was hardly unknown on DOS systems, it was mainly reserved for PCs in large companies that connect to a LAN with Novell's NetWare. FreeDOS includes TCP / IP networks instead of Novell's proprietary IPX.

You can go online with the text-based links browser or the graphic dillo. You can also transfer files to and from a virtual machine using a built-in FTP server, but you can also mount a VHD drive on your local computer. You can install all of this from FDIMPLES in the "Network" section.

FreeDOS is an interesting and fun non-Linux open source operating system

FreeDOS brings back some of the fun and inconvenience of MS-DOS. Should you be using it? A normal user may not have much to do with a single-tasking operating system for a single user, but enthusiasts, especially those who have had their first computer experience with DOS, might find FreeDOS an exercise in nostalgia. It's worth taking a spin in a virtual machine It might make you appreciate modern systems better.

If you're interested in other non-Linux open source operating systems and you have a Raspberry Pi, there are options, although many of them will run on regular PCs as well, like FreeDOS does.

9 Raspberry Pi Operating Systems That Are Not Linux

Are you looking for a Raspberry Pi operating system but want to avoid Linux? Check out this list of non-Linux Raspberry Pi operating systems for ideas.

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About the author

David Delony
(36 published articles)

David is a freelance writer living in the Pacific Northwest but originally from the Bay Area. He has been passionate about technology since childhood. David's interests include reading, watching quality TV shows and movies, retro games, and collecting records.

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By David Delony

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