DECnet is a proprietary suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus making DEC into a networking powerhouse in the 1980s. In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ... Digital Equipment Corporation was a pioneering company in the American computer industry. ... 1975 (MCMLXXV) was a common year starting on Wednesday (the link is to a full 1975 calendar). ... Dennis Ritchie and Ken Thompson at a PDP-11 The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... HP2114 minicomputer Minicomputer is a largely obsolete term for a class of multi-user computers which make up the middle range of the computing spectrum, in between the largest multi-user systems (mainframe computers) and the smallest single-user systems (microcomputers or personal computers). ... A peer-to-peer (or P2P) computer network is a network that relies on the computing power and bandwidth of the participants in the network rather than concentrating it in a relatively few servers. ... The 1980s in its most obvious sense refers to the decade between 1980 and 1989. ...

Initially built with four layers, it later (1992) evolved into a seven layer OSI compliant networking protocol, around the time when open systems (POSIX compliant, i.e. UNIX-like) were grabbing marketshare from the proprietary OSes like VAX/VMS and AlphaVMS. 1992 (MCMXCII) was a leap year starting on Wednesday. ... The Open Systems Interconnection (usually abbreviated to OSI) was a new effort in networking started in 1982 by the International Organization for Standardization (ISO), along with the ITU-T. Prior to OSI, networking was completely vendor-developed and proprietary, with protocol standards such as SNA and DECnet. ... POSIX is the collective name of a family of related standards specified by the IEEE to define the application program interface (API) for software designed to run on variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. ... Wikibooks has more about this subject: Guide to UNIX Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ...

DECnet was built right into the DEC flagship operating system (VAX/VMS) from its inception. Digital ported it to its own Ultrix variant of UNIX, as well as Apple Macintosh computers and PCs running both DOS and Windows under the name DEC Pathworks, transforming these systems into DECnet end-nodes on a network of VAX machines. More recently, an open-source version has been developed for the Linux OS: see Linux-DECnet on Sourceforge. VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i. ... OpenVMS V7. ... Ultrix was the brand name of Digital Equipment Corporations (DEC) native Unix systems. ... Wikibooks has more about this subject: Guide to UNIX Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... The Macintosh project started in early 1979 with Jef Raskin, an Apple employee, who envisioned an easy-to-use, low-cost computer for the average consumer. ... VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i. ... Tux, a cartoon penguin frequently featured sitting, is the official Linux mascot. ...

Brief Overview of the Evolution of DECnet

DECnet refers to a specific set of hardware and software networking products which implement the DIGITAL Network Architecture (DNA). The DIGITAL Network Architecture is essentially a set of documents which define the network architecture in general, states the specifications for each layer of the architecture, and describes the protocols which operate within each layer. Although network protocol analyzer tools tend to categorize all protocols from DIGITAL as "DECnet", strictly speaking, non-routed DIGITAL protocols such as LAT, SCS, AMDS, LAST/LAD are not DECnet protocols and are not part of the DIGITAL Network Architecture. A protocol stack is a particular software implementation of a computer networking protocol suite. ... A protocol analyzer is a hardware device or software used to verify that a protocol on a digital network is operating correctly, or to extract data about the protocol, possibly including statistics or data. ...

To trace the evolution of DECnet is to trace the development of DNA. The beginnings of DNA were in the early 1970s. DIGITAL published its first DNA specification at about the same time that IBM announced its Systems Network Architecture (SNA). Since that time, development of DNA has evolved through the following phases: International Business Machines Corporation (IBM, or colloquially, Big Blue) NYSE: IBM (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, NY, USA. The company manufactures and sells computer hardware, software, and services. ... Systems Network Architecture (SNA) is IBMs proprietary networking architecture created in 1974. ...

Phase I (1974) Support limited to 2 PDP-11s running the RSX-11 operating system only, with communication over point-to-point (DDCMP) links between nodes. 1974 (MCMLXXIV) is a common year starting on Tuesday (click on link for calendar). ... Dennis Ritchie and Ken Thompson at a PDP-11 The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... RSX-11: A family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation (DEC), common in the late 1970s and early 1980s, designed for and much used in process control, but also popular for program development. ... Digital Data Communications Message Protocol (DDCMP) was devised by Digital Equipment Corporation in 1974 to allow communication over point-to-point network links for its DECnet Phase I network protocol. ...

Phase II (1976) Support for networks of up to 32 nodes with multiple, different implementations which could interoperate with each other. Implementations expanded to included RSTS, TOPS-10 and TOPS-20 with communications between processors still limited to point-to-point links only. Introduction of file transfer (FAL), remote file access (DAP), task-to-task programming interfaces and network management features. 1976 (MCMLXXVI) is a leap year starting on Thursday (link will take you to calendar). ... RSTS/E (an acronym for Resource Sharing Time Sharing Extended) was a multi-user time-shared operating system developed by Digital Equipment Corporation (DEC) for the PDP-11 series of 16-bit minicomputers, and used primarily during the 1970s and 1980s, although some installations were still being upgraded well into... The TOPS-10 System was a computer operating system from Digital Equipment Corporation (DEC) for the PDP-10 released in 1964 and later on for the DEC-System10. ... The TOPS-20 operating system by DEC was the second proprietary OS for the PDP-10. ...

Phase III (1980). Support for networks of up to 255 nodes over point-to point and multi-drop links. Introduction of adaptive routing capability, downline loading (MOP), record access, a network management architecture, and gateways to other types of networks including IBM’s SNA and CCITT Recommendation X.25. 1980 (MCMLXXX) was a leap year starting on Tuesday. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... X.25 is an ITU-T standard protocol suite for WAN networks using the phone or ISDN system as the networking hardware. ...

Phase IV and Phase IV+ (1982). Phase IV was released initially to RSX-11 and VMS systems, later TOPS-20, TOPS-10, ULTRIX, VAXeln, and RSTS/E gained support. Support for networks of up to 64,449 nodes (63 areas of 1023 nodes), datalink capabilities expanded beyond DDCMP to include Ethernet local area network support as the datalink of choice, expanded adaptive routing capability to include hierarchical routing (areas, level 1 and level 2 routers), VMScluster support (cluster alias) and host services (CTERM). CTERM allowed a user on one computer to log into another computer remotely, performing the same function that Telnet does in the TCP/IP protocol stack. Digital also released a product called Pathworks that implemented much of DECnet Phase IV for DOS, and 16 and 32 bit Windows platforms (all the way through to Windows Server 2003). Ethernet is a frame-based computer networking technology for local area networks (LANs). ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... High-Level Data Link Control (HDLC) is a bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... 1982 (MCMLXXXII) is a common year starting on Friday of the Gregorian calendar. ... RSX-11: A family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation (DEC), common in the late 1970s and early 1980s, designed for and much used in process control, but also popular for program development. ... VMS is a three-letter abbreviation that can mean: Variable message sign, an electronic traffic sign often used on highways Virtual Memory System (another name for OpenVMS), an operating system Visual Memory System (better known as Visual Memory Unit), a storage device for the Sega Dreamcast console Volcanogenic Massive Sulfide... The TOPS-20 operating system by DEC was the second proprietary OS for the PDP-10. ... The TOPS-10 System was a computer operating system from Digital Equipment Corporation (DEC) for the PDP-10 released in 1964 and later on for the DEC-System10. ... Ultrix was the brand name of Digital Equipment Corporations (DEC) native Unix systems. ... VAXeln is a real-time operating system for MicroVAX. Trivia It was originally supposed to be named ELAN but DEC discovered at the last minute that it was trademarked in a European country where DEC wished to conduct business. ... RSTS/E (an acronym for Resource Sharing Time Sharing Extended) was a multi-user time-shared operating system developed by Digital Equipment Corporation (DEC) for the PDP-11 series of 16-bit minicomputers, and used primarily during the 1970s and 1980s, although some installations were still being upgraded well into... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... A local area network (LAN) is a computer network covering a small local area, like a home, office, or small group of buildings such as a college. ... Quit deleting my shit you cunt. ... TELNET is a network protocol used on the Internet or local area network LAN connections. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ...

Phase IV implemented an 8 layer architecture similar to the OSI (7 layer) model especially at the lower levels (see diagram below). Since the OSI standards were not yet fully developed at the time, many of the Phase IV protocols remained proprietary. The Open Systems Interconnection Reference Model (OSI Model or OSI Reference Model for short) is a layered abstract description for communications and computer network protocol design, developed as part of the Open Systems Interconnect initiative. ...

The Ethernet implementation was unusual in that the software changed the physical address of the Ethernet interface on the network to AA-00-04-00-xx-yy where xx-yy reflected the DECnet network address of the host. This allowed router-less LAN operation because the LAN address could be deduced from the DECnet address.

The initial implementations released were for VMS and RSX-11, later this expanded to virtually every operating system DIGITAL ever shipped with the notable exception of RT-11. OpenVMS V7. ... In computing, an operating system ( aka, OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... RT-11 (for Run Time or Real Time) was a real-time operating system for the DEC PDP-11. ...

At the same time that DECnet Phase IV was released, the company also released a proprietary protocol called LAT for terminal access via Terminal servers. Local Area Transport is a non-routable networking technology developed by Digital Equipment Corporation to enable them to connect their DS-200 (a. ... Originally, the first terminal servers were devices providing a connection between a so-called green screen dumb terminal and a host computer via an Ethernet. ...

Enhancements made to DECnet Phase IV eventually became known as DECnet Phase IV+, although systems running this protocol remained completely interoperable with DECnet Phase IV systems.

Phase V and Phase V+ (1987). Support for very large (architecturally unlimited) networks, a new network management model, local or distributed name service, improved performance over Phase IV. Move from a proprietary network to a Open Systems Interconnection (OSI) by integration of ISO standards to provide multi-vendor connectivity and compatibility with DNA Phase IV, the last two features resulted in a hybrid network architecture (DNA and OSI) with separate “towers” sharing an integrated transport layer. Transparent transport level links to TCP/IP were added via the IETF RFC 1006 (OSI over IP) and RFC 1859 (NSP over IP) standards (see diagram below). 1987 (MCMLXXXVII) is a common year starting on Thursday of the Gregorian calendar. ... The Open Systems Interconnection (usually abbreviated to OSI) was a new effort in networking started in 1982 by the International Organization for Standardization (ISO), along with the ITU-T. Prior to OSI, networking was completely vendor-developed and proprietary, with protocol standards such as SNA and DECnet. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... The Internet Engineering Task Force (IETF) is charged with developing and promoting Internet standards, in particular, those of the TCP/IP protocol suite. ... In internetworking and computer network engineering, Request for Comments (RFC) documents are a series of memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies. ...

It was later renamed DECnet/OSI to emphasize its OSI interconnectibility, and subsequently DECnet-Plus as TCP/IP protocols were incorporated.

References

• Carl Malamud, Analyzing DECnet/OSI Phase V. Van Hostrand Reinhold, 1991. ISBN 0442003757.

• James Martin, Joe Leben, DECnet Phase V: An OSI Implementation. Digital Press, 1992. ISBN 1555807690.