Editing NetBIOS (section)

==History and terminology==
NetBIOS is an operating system-level API that allows applications on computers to communicate with one another over a [[local area network]] (LAN). The API was created in 1983 by [[Sytek Inc]]. for software communication over [[IBM PC Network]] LAN technology.<ref name="barrie"/> On [[IBM PC Network]], as an API alone, NetBIOS relied on proprietary Sytek networking protocols for communication over the wire.<ref>{{Cite web |title=10. Assessing Windows Networking Services - Network Security Assessment, 2nd Edition [Book] |url=https://www.oreilly.com/library/view/network-security-assessment/9780596510305/ch10.html |access-date=2023-04-20 |website=www.oreilly.com |language=en |archive-date=20 April 2023 |archive-url=https://web.archive.org/web/20230420121049/https://www.oreilly.com/library/view/network-security-assessment/9780596510305/ch10.html |url-status=live }}</ref>

{{anchor|NetBEUI}}In 1985, IBM went forward with the [[Token Ring]] network scheme and produced an [[emulator]] of Sytek's NetBIOS API to allow NetBIOS-aware applications from the PC-Network era to work over IBM's new Token Ring hardware. This IBM emulator, named NetBIOS Extended User Interface (NetBEUI), expanded the base NetBIOS API created by Sytek with, among other things, the ability to deal with the greater node capacity of Token Ring. A new networking protocol, [[NetBIOS Frames|NBF]], was simultaneously produced by IBM to allow its NetBEUI API (their enhanced NetBIOS API) to provide its services over Token Ring – specifically, at the [[IEEE 802.2]] [[Logical Link Control]] layer.

In 1985, [[Microsoft]] created its own implementation of the NetBIOS API for its [[MS-Net]] networking technology. As in the case of IBM's Token Ring, the services of Microsoft's NetBIOS implementation were provided over the IEEE 802.2 Logical Link Control layer by the NBF protocol.<ref>{{Cite web |title=Getaway hardware for protocols |url=https://www.networking-hardware.com/juniper/service-gateway |access-date=2023-04-20 |website=www.networking-hardware.com |archive-date=26 March 2023 |archive-url=https://web.archive.org/web/20230326062716/https://www.networking-hardware.com/juniper/service-gateway |url-status=live }}</ref> However, the MS-Net was only delivered to [[Original equipment manufacturer|OEM]]s, and it was actually not a complete product, nor was it ready to communicate on the network in the form it was distributed. It lacked any implementation of [[OSI model|OSI]] Layers 1 to 4 ([[Physical layer|Physical]], [[Data link layer|Data link]], [[Network layer|Network]] and [[Transport layer|Transport]] Layers) and an OEM was expected to provide these implementations (in the form of a NetBIOS part) to make its version of MS-Net a complete and ready to use product. MS-Net accessed the network through the Microsoft's own variant of NetBIOS, which was split into two parts - the lower level part that OEMs had to provide implemented the NetBIOS calls that depended on layers 1-4, while the higher level part, provided by Microsoft, was hardware- and protocol-independent. This NetBIOS implementation supported the full NetBIOS API, but was called by invoking [[x86]] interrupt 0x2A, instead of IBM's standard interrupt 0x5C. The reliance on OEMs to implement parts of NetBIOS had the unfortunate side effect that different OEM versions of MS-Net and NetBIOS generally weren't able to communicate with one another. <ref>{{Cite web |title=Early Microsoft Networks {{!}} OS/2 Museum |url=http://www.os2museum.com/wp/early-microsoft-networks/ |access-date=2024-09-04 |language=en-US}}</ref> 

In 1986, [[Novell]] released Advanced [[Novell NetWare]] 2.0 featuring the company's own emulation of the NetBIOS API. Its services were encapsulated within NetWare's [[IPX/SPX]] protocol using the [[NetBIOS over IPX/SPX]] (NBX) protocol.

In 1987, a method of encapsulating NetBIOS in [[Transmission Control Protocol|TCP]] and [[User Datagram Protocol|UDP]] packets, [[NetBIOS over TCP/IP]] (NBT), was published. It was described in RFC 1001 ("Protocol Standard for a NetBIOS Service on a TCP/UDP Transport: Concepts and Methods") and RFC 1002 ("Protocol Standard for a NetBIOS Service on a TCP/UDP Transport: Detailed Specifications"). The NBT protocol was developed in order to "allow an implementation [of NetBIOS applications] to be built on virtually any type of system where the TCP/IP protocol suite is available," and to "allow NetBIOS interoperation in the Internet."

After the [[IBM PS/2|PS/2]] computer hit the market in 1987, IBM released the PC LAN Support Program, which included a driver offering the NetBIOS API.

There is some confusion between the names NetBIOS and NetBEUI. NetBEUI originated strictly as the [[moniker]] for IBM's enhanced 1985 NetBIOS emulator for Token Ring. The name NetBEUI should have died there, considering that at the time, the NetBIOS implementations by other companies were known simply as NetBIOS regardless of whether they incorporated the API extensions found in Token Ring's emulator. For MS-Net, however, Microsoft elected to name its implementation of the NBF protocol "NetBEUI" – naming its implementation of the transport protocol after IBM's enhanced version of the API.{{cn|date=June 2023|reason=A source needed to support the alleged controversy that the protocol implemented by NetBIOS emulator over 802.2 would be different between Token Ring and Ethernet networks.}} Consequently Microsoft file and printer sharing over [[Ethernet]] often continues to be called NetBEUI, with the name NetBIOS commonly used only in reference to file and printer sharing over [[TCP/IP]]. More accurately, the former is [[NetBIOS Frames]] (NBF), and the latter is [[NetBIOS over TCP/IP]] (NBT).

Since its original publication in a technical reference book from IBM, the NetBIOS API specification has become a [[de facto standard|''de facto'' standard]] in the industry despite originally supporting a maximum of only 80 PCs in a LAN.  This limitation was generally overcome industry-wide through the transition from NBF to NBT, under which, for example, Microsoft was able to switch to [[Domain Name System]] (DNS) for resolution of NetBIOS [[hostname]]s, having formerly used the LAN segment-compartmentalized NBF protocol itself to resolve such names in Windows [[Client–server model|client-server networks]].<ref name="barrie"/>