FreeDOS is a free and open source operating system variant of the classic MSDOS from the 90’s, just like DRDOS and PCDOS from the time. FreeDOS can be used to run legacy business software and classic games for MSDOS. In this example, FreeDOS 1.3 is installed as a guest in VirtualBox 6.1 on a FreeBSD 13.2 desktop computer.

Download FreeDOS.

Go to the website of FreeDOS and download the FreeDOS CDROM installer. The size of the file was 394 MB. Unpack the downloaded compressed archive.

$ wget https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/distributions/1.3/official/FD13-LiveCD.zip
--2023-05-03 21:31:14--  https://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/distributions/1.3/official/FD13-LiveCD.zip
Resolving www.ibiblio.org (www.ibiblio.org)... 152.19.134.40, 2610:28:3090:3000:0:bad:cafe:23
Connecting to www.ibiblio.org (www.ibiblio.org)|152.19.134.40|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 393058467 (375M) [application/zip]
Saving to: ‘FD13-LiveCD.zip’
$ unzip FD13-LiveCD.zip
Archive:  FD13-LiveCD.zip
 extracting: FD13BOOT.img  
 extracting: FD13LIVE.iso  
 extracting: readme.txt

The readme.txt has more information about disk space requirements, installer variants and installation instructions. 275 MB is needed for a full installation with applications and games.

$ more readme.txt

Create virtual machine for FreeDOS in VirtualBox.

Start VirtualBox and create a new virtual machine. If fixed size VHD is used, then the file system can be mounted by FreeBSD and other operating systems later.

Name = FREEDOS
Type = Other
Version = DOS
Memory size = 32
Hard disk = Create a virtual hard disk now
File size = 500,00 MB
Hard disk file type = VHD (Virtual Hard Disk)
Storage on physical hard disk = Fixed size

Install FreeDOS.

Load the CDROM installer on the FD13LIVE.ISO image and start the new FreeDOS virtual machine. Install FreeDOS, using the installer. This includes formatting and partitioning the virtual harddisk. When complete, remove the CDROM and reboot.

The FreeDOS installer.

Using FreeDOS.

FreeDOS will now boot and you will be presented with the well known DOS prompt. The FreeDOS virtual computer can be stopped or shutdown with the shutdown command. Rebooting can be done with the reboot command. More about FreeDOS commands can be found with the help command.

The prompt in FreeDOS.
Navigator 2.11 in FreeDOS.
King’s Quest 3 in FreeDOS.
Doom in FreeDOS.

Transfer files to FreeDOS.

You might want to install legacy business software or classic DOS games by transfering files to and from FreeDOS. This part is unfortunately badly documented by FreeDOS and various helpfull sites out there. Some sites mention a built-in FTP server, known by the name MTCP FTP server. However, also this program is badly documented and there is no connection between the commands, error messages and the online documentation. It is my experience, that the best way is mounting the FreeDOS file system to your local file system. This is different from system to system, but in this example, it is done with the built-in mdconfig and mount utilities in FreeBSD 13.2.

# mdconfig /zvbox/guests/FREEDOS/FREEDOS.vhd
md0
# ls /dev/md0*
/dev/md0	/dev/md0s1
# gpart show md0
=>      1  1024000  md0  MBR  (500M)
        1       62       - free -  (31K)
       63  1023057    1  fat16  [active]  (500M)
  1023120      881       - free -  (441K)
# mount -t msdosfs /dev/md0s1 /mnt
# ls /mnt
APPS		FDAUTO.BAT	FREEDOS		KERNEL.SYS	PGME
COMMAND.COM	FDCONFIG.SYS	GAMES		NET		UTIL
# cp -r FOOBAR /mnt/APPS/
# umount /mnt

More about FreeDOS.

Official homepage of FreeDOS.