MS-Net, sometimes stylized asMS-NET, is anetwork operating system (NOS) sold byMicrosoft in the 1980s.

MS-Net is not a complete networking system of its own; Microsoft licensed it to vendors who used it as the basis for server programs that ran onMS-DOS, porting it to their own underlying networking hardware and adding services on top. Version 1.0 was announced on 14 August 1984 and released along with thePC/AT on 2 April 1985. A number of MS-Net products were sold during the late 1980s, before it was replaced byLAN Manager in 1990.

MS-Net's network interface is based onIBM'sNetBIOS Frames protocol definition, which allows it to be ported to different networking systems with relative ease. It does not implement the entire NetBIOS protocol, however, only the small number of features required for the server role. One key feature that was not implemented was NetBIOS's name management routines, a feature third parties often added back in. The system also supplies the program REDIR.EXE, which allows transparent file access from DOS machines to any MS-Net based server.

Several products from the mid-to-late-1980s were based on the MS-Net system. IBM's PC-Net is a slightly modified version of the MS-Net system typically used withToken Ring. Microsoft partnered with3Com to produce the more widely used3+Share system running on a 3Com networking stack based on theXNS protocol onEthernet. Other well-known systems, includingBanyan VINES andNovell NetWare, are not based on MS-Net, usingUnix and a custom OS, respectively. They do, however, allow access to their own files via the REDIR.EXE.

In 1988 MS-Net was the second most-popular NOS with 17.1% market share, below NetWare but aboveAppleTalk.^[1] MS-Net was sold only for a short period of time. Microsoft and 3Com collaborated on a replacement known asLAN Manager running onOS/2, using the newServer Message Block standard for file transfer. 3Com's version of the product retains their XNS-based protocol, but 3Com soon abandoned the server market. Microsoft's version remained based on NetBIOS and supported a number of underlying protocols and hardware. LAN Manager was itself replaced in 1993 byWindows NT 3.1.

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• net (command)

• "IBM PC and PC-Compatible NOSs Compared", U-M Computing News, Volume 2, Number 13 (1987), pp. 4–11.

• Discontinued Microsoft operating systems
• Network operating systems
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