MS-DOS / FreeDOS guest setup

August 7, 2026 ยท View on GitHub

Note

CPU Idling: For historical reasons, DOS-like systems do not support power-saving operations. One effect is that the CPU is running in a busy spin-loop when simply waiting for user input. CPU Idling aims to avoid this by making use of the HLT instruction under certain conditions to reduce CPU power consumption (and thus heat).

If you plan to install MS-DOS as the base OS for Windows you have the option to enable CPU Idling (a) exclusively under DOS, (b) exclusively under Windows or (c) under both (depending on how you plan to use the installation).

Enabling support for CPU Idling is recommended, but not required.

1. Installing MS-DOS 6.22

Download:

Go to https://copy.sh/v86/ and select custom settings:

  • Floppy disk image: dos622/Disk 1.img
  • Hard disk image: select create empty hard disk to create a blank disk of 64 MB (for example)

Boot v86, follow the instructions and select defaults. Use the v86 Eject floppy image / Insert floppy image button to swap floppies dos622/Disk 2.img and dos622/Disk 3.img when the installer asks for it.

When finished, export hard disk image C: using v86 button Get hard disk image.

1.1 CPU Idling

Download:

  • DOSID251.zip [28,9 KB]
    CPUidle for DOS (DOSidle), extract DOSIDLE.EXE to floppy image dosidle.img

Boot v86, insert floppy image dosidle.img and install DOSIDLE.EXE using:

COPY A:DOSIDLE.EXE C:\

Eject the floppy image, then open AUTOEXEC.BAT in an editor using:

EDIT C:\AUTOEXEC.BAT

and append new line:

C:\DOSIDLE

Save and exit, export you hard disk image and reboot.

2. Installing FreeDOS 1.4

Download from the FreeDOS Homepage:

  • FD14-LiveCD.zip [280 MB]
    FreeDOS for everyone 1.4, unpack FD14LIVE.iso [301 MB]

There are more optional packages on the Bonus CD FD14-BonusCD.zip.

Go to https://copy.sh/v86 and select custom settings:

  • CD image: FD14LIVE.iso
  • Hard disk image: select create empty hard disk to create a blank disk of 64 MB (for example)

Boot v86, follow the installation instructions and select defaults, export your HD image when done.

To install extra packages, insert Live CD FD14LIVE.iso (or Bonus CD FD14BNS.iso) and run the FreeDOS package manager:

FDIMPLES

2.1 CPU Idling

FreeDOS provides a tool FDAPM to control Advanced Power Management (APM) settings.

Run EDIT C:\FDAUTO.BAT and append line (after END:):

FDAPM APMDOS

Save and exit, then reboot.

Source

2.2 Networking

For networking support add these packages from Live CD FD14LIVE.iso:

[+] Networking
    [X] FDNET     Basic networking support package
    [X] MTCP      A collection of TCP/IP tools

Click OK to install the packages and to close the package manager, then create C:\net\fdnet\fdnetpd.bat (FreeDOS doesn't auto-detect v86's NIC):

ECHO NE2000.COM 0x60 0xA 0x300 > NET\FDNET\FDNETPD.BAT

Reboot, wait for a DHCP lease and then test networking with:

NET\MTCP\HTGET.EXE http://copy.sh/v86/

3. FAT-formatted disk images

You need a bootable DOS-floppy image that contains FDISK.EXE and FORMAT.COM (or something similar) in order to create floppy and hard disk images using v86, for example msdos622-boot-fd.img (TODO: upload to copy.sh website).

3.1 Creating FAT-formatted floppy disks

Go to https://copy.sh/v86 and select custom settings:

  • Floppy disk image: msdos622-boot-fd.img
  • Second floppy disk image: select create empty floppy disk to create a blank disk image

Boot v86. In order to format the empty floppy disk in B: enter:

FORMAT B:

When finished, export the floppy disk image in B: using v86 button Get second floppy image.

3.2 Creating DOS-partitioned and FAT-formatted hard disks

Go to https://copy.sh/v86 and select custom settings:

  • Floppy disk image: msdos622-boot-fd.img
  • Hard disk image: select create empty hard disk to create a blank disk image
  • Boot order: select Floppy / Hard disk / CD

Boot v86. In order to partition the empty hard disk, enter at the command prompt:

FDISK

Use the defaults to create a single partition that fills the entire hard disk, reboot.

Next, to format the new partition C: enter:

FORMAT C:

When finished, export the hard disk image C: using v86 button Get hard disk image.

3.3 Editing FAT-formatted disk images

3.3.1 Windows

Use WinImage for floppy and hard disk images (and other image types).

3.3.2 Linux

Floppy disks

Use mtools to directly copy files from/to floppy images using the -i command line flag, for example (in mtools, :: is the drive name of the image file mounted using -i):

# copy file1.txt from floppy-disk.img to current working directory
mcopy -i floppy-disk.img ::file1.txt .

# copy file2.txt from current working directory to floppy-disk.img
mcopy -i floppy-disk.img file2.txt ::

Hard disks

Mount example hard disk image hard-disk.img into directory /mnt:

# attach loop device 0 to image file "hard-disk.img"
sudo losetup -P /dev/loop0 hard-disk.img
# mount first partition into directory "/mnt"
sudo mount /dev/loop0p1 /mnt

Now perform file operations on /mnt. When done umount the image again using:

# unmount partition from directory
sudo umount /mnt
# detach loop device from disk image
sudo losetup -d /dev/loop0