CHAOSnet
Encyclopedia
Chaosnet was first developed by Thomas Knight and Jack Holloway at MIT's
AI Lab in 1975 and thereafter. It refers to two separate, but closely related, technologies. The more widespread was a set of computer
communication packet-based protocols intended to connect the then-recently developed and very popular (within MIT) Lisp machine
s; the second was one of the earliest local area network
hardware implementations.
The Chaosnet protocol originally used the latter, an implementation over CATV coaxial cable modeled on the early Xerox PARC
Ethernet
, the early ARPANET
, and Transmission Control Protocol
(TCP). It was a contention-based system intended to work over a range, that included a pseudo-slotted feature intended to reduce collisions, which worked by passing a virtual token of permission from host to host; successful packet transmissions updated each host's knowledge of which host had the token at that time. Collisions caused a host to fall silent for a duration depending on the distance from the host it collided with. Collisions were never a real problem, and the pseudo-slotting fell into disuse.
Chaosnet's network topology was usually series of linear (not circular) cables, each up to a maximum of a kilometer and roughly 12 clients. The individual segments were interconnected by "bridges" (much in the ARPANET mold), generally older computers like PDP-11
s with two network interfaces.
The protocols were also later implemented as a payload that could be carried over Ethernet (usually the later variety). Chaosnet was specifically for LANs; features to support WANs
were left out for the sake of simplicity.
Chaosnet can be regarded as a contemporary of both the PUP
protocols invented by PARC, and the Internet Protocol
, and was recognized as one of the other network types (other than "IN") in the Domain Name System
. BIND
uses a built-in pseudo-top-level-domain in the "CHAOS class" for retrieving information about a running DNS server.http://www.bind9.net/manual/bind/9.3.2/Bv9ARM.ch06.html#builtin
The original GNU Manifesto
mentioned that it aimed to, among other things, support the Chaosnet protocol.
Symbolics
, a maker of the Lisp machine
s, licensed the MIT Chaosnet hardware and software implementation from the CADR
computer design.
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
AI Lab in 1975 and thereafter. It refers to two separate, but closely related, technologies. The more widespread was a set of computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
communication packet-based protocols intended to connect the then-recently developed and very popular (within MIT) Lisp machine
Lisp machine
Lisp machines were general-purpose computers designed to efficiently run Lisp as their main software language. In a sense, they were the first commercial single-user workstations...
s; the second was one of the earliest local area network
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
hardware implementations.
The Chaosnet protocol originally used the latter, an implementation over CATV coaxial cable modeled on the early Xerox PARC
Xerox PARC
PARC , formerly Xerox PARC, is a research and co-development company in Palo Alto, California, with a distinguished reputation for its contributions to information technology and hardware systems....
Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
, the early ARPANET
ARPANET
The Advanced Research Projects Agency Network , was the world's first operational packet switching network and the core network of a set that came to compose the global Internet...
, and Transmission Control Protocol
Transmission Control Protocol
The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...
(TCP). It was a contention-based system intended to work over a range, that included a pseudo-slotted feature intended to reduce collisions, which worked by passing a virtual token of permission from host to host; successful packet transmissions updated each host's knowledge of which host had the token at that time. Collisions caused a host to fall silent for a duration depending on the distance from the host it collided with. Collisions were never a real problem, and the pseudo-slotting fell into disuse.
Chaosnet's network topology was usually series of linear (not circular) cables, each up to a maximum of a kilometer and roughly 12 clients. The individual segments were interconnected by "bridges" (much in the ARPANET mold), generally older computers like PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
s with two network interfaces.
The protocols were also later implemented as a payload that could be carried over Ethernet (usually the later variety). Chaosnet was specifically for LANs; features to support WANs
Wide area network
A wide area network is a telecommunication network that covers a broad area . Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations...
were left out for the sake of simplicity.
Chaosnet can be regarded as a contemporary of both the PUP
PARC Universal Packet
The PARC Universal Packet was one of the two earliest internetwork protocol suites; it was created by researchers at Xerox PARC in the mid-1970s...
protocols invented by PARC, and the Internet Protocol
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
, and was recognized as one of the other network types (other than "IN") in the Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
. BIND
BIND
BIND , or named , is the most widely used DNS software on the Internet.On Unix-like operating systems it is the de facto standard.Originally written by four graduate students at the Computer Systems Research Group at the University of California, Berkeley , the name originates as an acronym from...
uses a built-in pseudo-top-level-domain in the "CHAOS class" for retrieving information about a running DNS server.http://www.bind9.net/manual/bind/9.3.2/Bv9ARM.ch06.html#builtin
The original GNU Manifesto
GNU Manifesto
The GNU Manifesto was written by Richard Stallman and published in March 1985 in Dr. Dobb's Journal of Software Tools as an explanation and definition of the goals of the GNU Project, and to call for participation and support. It is held in high regard within the free software movement as a...
mentioned that it aimed to, among other things, support the Chaosnet protocol.
Symbolics
Symbolics
Symbolics refers to two companies: now-defunct computer manufacturer Symbolics, Inc., and a privately held company that acquired the assets of the former company and continues to sell and maintain the Open Genera Lisp system and the Macsyma computer algebra system.The symbolics.com domain was...
, a maker of the Lisp machine
Lisp machine
Lisp machines were general-purpose computers designed to efficiently run Lisp as their main software language. In a sense, they were the first commercial single-user workstations...
s, licensed the MIT Chaosnet hardware and software implementation from the CADR
Lisp machine
Lisp machines were general-purpose computers designed to efficiently run Lisp as their main software language. In a sense, they were the first commercial single-user workstations...
computer design.
External links
- Cisco's Implementation of Chaosnet
- Chaosnet implementations - contains errors
- Another reference to AI Memo 628
- A better scan of AI Memo 628 than the one below (pdf)
- [ftp://publications.ai.mit.edu/ai-publications/500-999 Another place to get AI Memos 500 to 999] (FTP)
- Chaosnet (Linux source driver)