Microsoft long ago abandoned DOS in favor of Windows which is what everyone now uses. Windows 10 Professional x64 includes Hyper-V which can make it possible to run MS-DOS in a virtual machine.

MS-DOS 6.22 was the last version released in June 1994. Following that Windows 95 took over, You can download a ready to use VHD that can be setup with Hyper-V ready to go.

The when you create a new virtual machine, the defaults are OK and instead of making a new virtual hard disk, the MS DOS VHD is used. Then once it’s done, you can boot up DOS with a 2GB hard disk which is as large as it can manage.

Even though the virtual machine has more memory, DOS is limited to 640kB. DOS 6.22 can recognize extended memory up to 64MB. Hyoer-V defaults to 512MB so change it to 64MB and disable dynamic memory.

Using a second VHD its possible to mount that with Disk Manager and copy DOS programs to it. Then that VHD can become drive D: to MS DOS and games or productivity programs can be copied as needed.

It’s also possible to mount the DOS virtual hard disk and copy files to that as well. Disk manager can attach a VHD to the file system, which then allows easy copy of files back and forth.


DOS 6.22 memory

MS-DOS 6,22 can use up to 64MB of memory which is shown as extended memory. Many games used a DOS extender that allowed them to use extended memory. DOS4GW.EXE is the DOS extender mostly widely seen with games.


Microsoft MS-DOS versions 4.0 and later allow FDISK to partition hard disks up to 4 gigabytes (GB) in size. However, the MS-DOS file allocation table (FAT) file system can support only 2 GB per partition. Because of this fact, a hard disk between 2 and 4 GB in size must be broken down into multiple partitions, each of which does not exceed 2 GB.

The 2-GB partition limit is imposed by the maximum number of clusters and the largest cluster size supported by the FAT file system. The FAT file system is limited to 65,525 clusters. The size of a cluster must be a power of 2 and less than 65,536 bytes–this results in a maximum cluster size of 32,768 bytes (32K). Multiplying the maximum number of clusters (65,525) by the maximum cluster size (32,768) equals 2 GB.

In 1994 the Maxtor 540MB drive was extreme and DOS and BIOS limitations prevented the full use of the disk.

DOS 6.22 disk


We have a blank DOS floppy and empty VHD already partitioned and formatted for MS-DOS use. Save the zip file to your VHD folder and keep it handy in case a new floppy or hard disk is needed. MS-DOS can use several 2GB hard disks easily.