Microsoft MS-DOS 2.10a [Wang Professional Computer OEM (r2.01)]
Released 1985 by WANG Labs, INC. 
For the Wang Professional Computer

Image quality: unused/unmodified

These are the system disks bundled with the Wang Professional 
Computer. Version "2.01" refers to the revision of the system disks 
containing MS-DOS 2.10a and utilities.

Important: These disks will not run on IBM PCs, IBM PC emulators, or
virtualizes. They are only intended to work on the Wang Professional
Computer.

The WANG Professional Computer is an 8086 based computer with a
unique architecture that is not IBM PC hardware compatible. This port
of MS-DOS permits it to run DOS applications that limit themselves to
DOS API calls (No BIOS calls or direct screen writes, for example).

Such computers are said to be "MS-DOS Compatible" but not "IBM PC
Compatible".

More information on the Wang Professional Computer is located here:
http://www.seasip.info/VintagePC/wangpc.html