Microsoft and IBM long ago abandoned OS/2 in favor of Windows which is what everyone now uses. Windows 8 Professional x64 includes Hyper-V which can make it possible to run MS-DOS in a virtual machine.
OS/2 is the replacement for MS-DOS that IBM developed along with Microsoft. Microsoft considered OS/2 to be a viable surecessor for MS-DOS given its support for more memory on the 80386 processors. The latest version of OS/2 is the Warp version for 32-bit processors.
FAT partitions under OS/2 are limited to a 2.1GB maximum size. HPFS partitions are limited to a 64GB maximum size.
OS/2 runs with Hyper-V fine so that any legacy applications desired can be used easily.