YouTuber Tech Tangents recorded a video about the difficulty he encountered installing FreeDOS on an IBM 5150. A similar problem will exist on any XT class system. He ended up essentially having to make his own distribution to get around the limitations. I’m sure he wishes he’d known about a FreeDOS derivative that already existed to solve his problem. That derivative is called SvarDOS.
Why not just run FreeDOS?
The problems getting FreeDOS running on XT-class hardware are threefold. The first problem is the lack of 360K or 720K installation media. FreeDOS came about in a time when 1.44 MB floppies were giving way to CD-ROM, so it’s really geared for installation from optical discs, flash memory, or network storage. Not low-capacity floppies.
The second problem is the sheer amount of storage required. 20 MB was a lot of storage on XT-type systems, but that’s just enough room to install FreeDOS and its bundled software. It doesn’t leave much for anything else.
And the third problem is that some of the software targets higher-end processors than the 8088/8086.
SvarDOS neatly solves all of these, allowing you to install off 360k or 720k floppies or any other size floppy for that matter, and it installs a compact base system about a megabyte and a half in size that will run on an 8088 or 8086 without issue.
What DOS you run on your XT-class system tends to be a personal choice, and you may even change your mind from time to time what you run. There’s an argument for MS-DOS 3.31, MS-DOS 6.22, PC-DOS 2000, and, for that matter, FreeDOS. One cool thing is that you can now get an open source BIOS for certain 8088 systems. So it is possible to run an 8088 with entirely open source software, including the BIOS and DOS. But it’s a lot more practical if you use SvarDOS rather than trying to use the official FreeDOS on your open source XT.
Giving SvarDOS a whirl
I decided to try out SvarDOS on my Tandy 1000 to see what it’s like. I’m happy to report it booted up and ran just fine on my Tandy 1000, with an NEC V20 CPU running at 7.16 MHz. I also didn’t find any compatibility issues, though I didn’t try every piece of software I have. But one thing I did notice is it seems to boot more slowly than MS-DOS 6.22, and it has the same long delay on large disk partitions. If anything, it’s longer than on MS-DOS. So you still need FreeSP if you run SvarDOS on a vintage PC with a large drive.
It supports FAT32, but I can’t imagine many people use FAT32 on XT-class systems. I have no reason to try it.
One thing I really liked about SvarDOS is SVED, its text editor. It’s only 6.7K on disk and it’s not a full featured editor by any stretch, but it is a full screen editor with all the core functionality you need to edit your autoexec.bat and config.sys files, and it loads and runs very quickly, even on an XT-class machine. So I copied it over to the drive I run MS-DOS on as well. For quick edits on a slower machine, SVED is a keeper.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.