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Microsoft Virtual PC 2004

Virtual Machine Additions for MS-DOS



Microsoft Virtual Machine Additions are a set of utility programs to enhance the functionality and performance of Virtual Machines. In addition, you can easily share a drive letter or path from the host computer making it accessible to the guest operating system.

The following programs are installed by default when adding the DOS Virtual Machine Additions:

Filename Description


Virtual CD-ROM Device Driver

FSHARE.EXE File Sharing Device Driver
IDLE.COM Virtual Machine CPU Idle Program
MOUSE.COM Mouse Device Driver

This document assumes that you have already created a Virtual Machine running DOS 6.22. If not, please review the notes section at the end of this document.


Start the MS-DOS 6.22 Virtual Machine. Select the "Floppy" menu tab at the top of the screen (see screen shot below) and select "Capture Floppy Image". Select the file "C:\Program Files\Microsoft Virtual PC\Microsoft Virtual Additions\DOS Virtual Machine Additions".  After successfully capturing the Virtual Floppy Image, restart the Virtual Machine. From the DOS prompt of the DOS Virtual Machine, execute "a:\dosadd.bat". This will complete the installation of the DOS Virtual Machine Additions.

Once the command has been run you will receive a message that states you have successfully installed DOS Virtual Machine Additions.  Eject the DOS Virtual Machine Additions virtual floppy disk and restart the virtual machine. 

Attaching "Shared Drives" to Virtual Machine

Now that you have the DOS Virtual Machine Additions installed, your virtual machine can now be used to access information on the physical computer.

The Shared folders option in the settings of your virtual machine allows you to access a folder or volume on a host computer as if it were a network share.  A shared folder can be shared each time a virtual machine boots up.  You can not share folders directly between virtual machines, but multiple guest machines can share a folder on the host operating system. 

NOTE:  When creating a shared folder, you must assign it to a drive letter that is not already being used by a drive or device in the virtual machine operating system. If two drives or devices are assigned to the same drive letter, the shared drive will not appear in the virtual machine operating system.




Installing MS-DOS 6.22

Begin by creating and configuring a new virtual machine with the specifications that best fit your machine.  Once you have completed setting up you new virtual machine you can then begin to install your operating system.  The steps for installing DOS are as follows:

  • Insert the MS-DOS 6.22 Disk 1 into your computerís floppy drive.
  • Read the MS-DOS 6.22 Setup screen, then press Enter to continue with the installation.
  • Confirm the time, date, and keyboard settings, then press Enter.
  • Next, you will be asked to confirm the installation directory. The default is C:\DOS, which you should accept.
  • Press Enter to begin the installation process.
  • You will be prompted for the installation floppies as the setup progresses. Follow the directions on the screen as they instruct you to insert the correct floppy and press Enter to continue.
  • Once the final floppy has been copied, you will be asked to remove all floppies and then restart your virtual machine, it will then restart using MS-DOS 6.22.
  • Once the virtual machine reboots, you will receive a command prompt. You can confirm that you installed the correct operating system by confirming the version number. At the command prompt, type the command "ver". 
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