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ARPANET

The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switched network with distributed control and one of the first computer networks to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was established by the Advanced Research Projects Agency (now DARPA) of the United States Department of Defense.

Building on the ideas of J. C. R. Licklider, Bob Taylor initiated the ARPANET project in 1966 to enable resource sharing between remote computers. Taylor appointed Larry Roberts as program manager. Roberts made the key decisions about the request for proposal to build the network. He incorporated Donald Davies' concepts and designs for packet switching, and sought input from Paul Baran on dynamic routing. In 1969, ARPA awarded the contract to build the Interface Message Processors (IMPs) for the network to Bolt Beranek & Newman (BBN). The design was led by Bob Kahn who developed the first protocol for the network. Roberts engaged Leonard Kleinrock at UCLA to develop mathematical methods for analyzing the packet network technology.

The first computers were connected in 1969 and the Network Control Protocol was implemented in 1970, development of which was led by Steve Crocker at UCLA and other graduate students, including Jon Postel and Vint Cerf. The network was declared operational in 1971. Further software development enabled remote login and file transfer, which was used to provide an early form of email. The network expanded rapidly and operational control passed to the Defense Communications Agency in 1975.

Bob Kahn moved to DARPA and, together with Vint Cerf at Stanford University, formulated the Transmission Control Program, which incorporated concepts from the French CYCLADES project directed by Louis Pouzin. As this work progressed, a protocol was developed by which multiple separate networks could be joined into a network of networks. Version 4 of TCP/IP was installed in the ARPANET for production use in January 1983 after the Department of Defense made it standard for all military computer networking.

Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In the early 1980s, the NSF funded the establishment of national supercomputing centers at several universities and provided network access and network interconnectivity with the NSFNET project in 1986. The ARPANET was formally decommissioned in 1990, after partnerships with the telecommunication and computer industry had assured private sector expansion and commercialization of an expanded worldwide network, known as the Internet.

Inspiration
Historically, voice and data communications were based on methods of circuit switching, as exemplified in the traditional telephone network, wherein each telephone call is allocated a dedicated end-to-end electronic connection between the two communicating stations. The connection is established by switching systems that connected multiple intermediate call legs between these systems for the duration of the call.

The traditional model of the circuit-switched telecommunication network was challenged in the early 1960s by Paul Baran at the RAND Corporation, who had been researching systems that could sustain operation during partial destruction, such as by nuclear war. He developed the theoretical model of distributed adaptive message block switching. However, the telecommunication establishment rejected the development in favor of existing models. Donald Davies at the United Kingdom's National Physical Laboratory (NPL) independently arrived at a similar concept in 1965.

The earliest ideas for a computer network intended to allow general communications among computer users were formulated by computer scientist J. C. R. Licklider of Bolt Beranek and Newman (BBN), in April 1963, in memoranda discussing the concept of the "Intergalactic Computer Network". Those ideas encompassed many of the features of the contemporary Internet. In October 1963, Licklider was appointed head of the Behavioral Sciences and Command and Control programs at the Defense Department's Advanced Research Projects Agency (ARPA). He convinced Ivan Sutherland and Bob Taylor that this network concept was very important and merited development, although Licklider left ARPA before any contracts were assigned for development.

Sutherland and Taylor continued their interest in creating the network, in part, to allow ARPA-sponsored researchers at various corporate and academic locales to utilize computers provided by ARPA, and, in part, to quickly distribute new software and other computer science results. Taylor had three computer terminals in his office, each connected to separate computers, which ARPA was funding: one for the System Development Corporation (SDC) Q-32 in Santa Monica, one for Project Genie at the University of California, Berkeley, and another for Multics at the Massachusetts Institute of Technology. Taylor recalls the circumstance: "For each of these three terminals, I had three different sets of user commands. So, if I was talking online with someone at S.D.C., and I wanted to talk to someone I knew at Berkeley, or M.I.T., about this, I had to get up from the S.D.C. terminal, go over and log into the other terminal and get in touch with them. I said, 'Oh Man!', it's obvious what to do: If you have these three terminals, there ought to be one terminal that goes anywhere you want to go. That idea is the ARPANET".

Donald Davies' work caught the attention of ARPANET developers at Symposium on Operating Systems Principles in October 1967. He gave the first public presentation, having coined the term packet switching, in August 1968 and incorporated it into the NPL network in England. The NPL network and ARPANET were the first two networks in the world to implement packet switching. Roberts said the computer networks built in the 1970s were similar "in nearly all respects" to Davies' original 1965 design.

Creation
In February 1966, Bob Taylor successfully lobbied ARPA's Director Charles M. Herzfeld to fund a network project. Herzfeld redirected funds in the amount of one million dollars from a ballistic missile defense program to Taylor's budget. Taylor hired Larry Roberts as a program manager in the ARPA Information Processing Techniques Office in January 1967 to work on the ARPANET. Roberts met Paul Baran in February 1967, but did not discuss networks.

Roberts asked Frank Westervelt to explore the questions of message size and contents for the network, and to write a position paper on the intercomputer communication protocol including “conventions for character and block transmission, error checking and re transmission, and computer and user identification." In April 1967, ARPA held a design session on technical standards. The initial standards for identification and authentication of users, transmission of characters, and error checking and retransmission procedures were discussed. Roberts' proposal was that all mainframe computers would connect to one another directly. The other investigators were reluctant to dedicate these computing resources to network administration. Wesley Clark proposed minicomputers should be used as an interface to create a message switching network. Roberts modified the ARPANET plan to incorporate Clark's suggestion and named the minicomputers Interface Message Processors (IMPs).

The plan was presented at the inaugural Symposium on Operating Systems Principles in October 1967. Donald Davies' work on packet switching and the NPL network, presented by a colleague (Roger Scantlebury), and that of Paul Baran, came to the attention of the ARPA investigators at this conference. Roberts applied Davies' concept of packet switching for the ARPANET, and sought input from Paul Baran on dynamic routing. The NPL network was using line speeds of 768 kbit/s, and the proposed line speed for the ARPANET was upgraded from 2.4 kbit/s to 50 kbit/s.

By mid-1968, Roberts and Barry Wessler wrote a final version of the IMP specification based on a Stanford Research Institute (SRI) report that ARPA commissioned to write detailed specifications describing the ARPANET communications network. Roberts gave a report to Taylor on 3 June, who approved it on 21 June. After approval by ARPA, a Request for Quotation (RFQ) was issued for 140 potential bidders. Most computer science companies regarded the ARPA proposal as outlandish, and only twelve submitted bids to build a network; of the twelve, ARPA regarded only four as top-rank contractors. At year's end, ARPA considered only two contractors and awarded the contract to build the network to BBN in January 1969. The initial, seven-person BBN team were much aided by the technical specificity of their response to the ARPA RFQ, and thus quickly produced the first working system. The "IMP guys" were led by Frank Heart; the theoretical design of the network was led by Bob Kahn; the team included Dave Walden, Severo Ornstein, William Crowther and several others. The BBN-proposed network closely followed Roberts' ARPA plan: a network composed of small computers, the IMPs (similar to the later concept of routers), that functioned as gateways interconnecting local resources. Routing, flow control, software design and network control were developed by the BBN team. At each site, the IMPs performed store-and-forward packet switching functions and were interconnected with leased lines via telecommunication data sets (modems), with initial data rates of 56 kbit/s. The host computers were connected to the IMPs via custom serial communication interfaces. The system, including the hardware and the packet switching software, was designed and installed in nine months. The BBN team continued to interact with the NPL team with meetings between them taking place in the U.S. and the U.K.

The first-generation IMPs were built by BBN using a rugged computer version of the Honeywell DDP-516 computer, configured with 24 KB of expandable magnetic-core memory, and a 16-channel Direct Multiplex Control (DMC) direct memory access unit. The DMC established custom interfaces with each of the host computers and modems. In addition to the front-panel lamps, the DDP-516 computer also features a special set of 24 indicator lamps showing the status of the IMP communication channels. Each IMP could support up to four local hosts and could communicate with up to six remote IMPs via early Digital Signal 0 leased telephone lines. The network connected one computer in Utah with three in California. Later, the Department of Defense allowed the universities to join the network for sharing hardware and software resources.

Debate about design goals
According to Charles Herzfeld, ARPA Director (1965–1967):"The ARPANET was not started to create a Command and Control System that would survive a nuclear attack, as many now claim. To build such a system was, clearly, a major military need, but it was not ARPA's mission to do this; in fact, we would have been severely criticized had we tried. Rather, the ARPANET came out of our frustration that there were only a limited number of large, powerful research computers in the country, and that many research investigators, who should have access to them, were geographically separated from them."

The ARPANET used distributed computation, and incorporated frequent re-computation of routing tables (automatic routing was technically challenging at the time). These features increased the survivability of the network in the event of significant interruption. Furthermore, the ARPANET was designed to survive subordinate-network losses. However, the Internet Society agrees with Herzfeld in a footnote in their online article, A Brief History of the Internet:

"It was from the RAND study that the false rumor started, claiming that the ARPANET was somehow related to building a network resistant to nuclear war. This was never true of the ARPANET, but was an aspect of the earlier RAND study of secure communication. The later work on internetworking did emphasize robustness and survivability, including the capability to withstand losses of large portions of the underlying networks."

Paul Baran, the first to put forward a theoretical model for communication using packet switching, conducted the RAND study referenced above. Though the ARPANET did not exactly share Baran's project's goal, he said his work did contribute to the development of the ARPANET. Minutes taken by Elmer Shapiro of Stanford Research Institute at the ARPANET design meeting of 9–10 October 1967 indicate that a version of Baran's routing method ("hot potato") may be used, consistent with the NPL team's proposal at the Symposium on Operating System Principles in Gatlinburg.

Later, in the 1970s, ARPA did emphasize the goal of "command and control". According to Stephen J. Lukasik, who was deputy director (1967–1970) and Director of DARPA (1970–1975):

"The goal was to exploit new computer technologies to meet the needs of military command and control against nuclear threats, achieve survivable control of US nuclear forces, and improve military tactical and management decision making."

Implementation
The first four nodes were designated as a testbed for developing and debugging the 1822 protocol, which was a major undertaking. While they were connected electronically in 1969, network applications were not possible until the Network Control Protocol was implemented in 1970 enabling the first two host-host protocols, remote login (Telnet) and file transfer (FTP) which were specified and implemented between 1969 and 1973. The network was declared operational in 1971. Network traffic began to grow once email was established at the majority of sites by around 1973.

Initial four hosts
The initial ARPANET configuration linked UCLA, ARC, UCSB, and the University of Utah School of Computing. The first node was created at UCLA, where Leonard Kleinrock could evaluate network performance and examine his theories on message delay. The locations were selected not only to reduce leased line costs but also because each had specific expertise beneficial for this initial implementation phase:

 * University of California, Los Angeles (UCLA), where Kleinrock had established a Network Measurement Center (NMC), with an SDS Sigma 7 being the first computer attached to it;
 * The Augmentation Research Center at Stanford Research Institute (now SRI International), where Douglas Engelbart had created the new NLS system, an early hypertext system, and would run the Network Information Center (NIC), with the SDS 940 that ran NLS, named "Genie", being the first host attached;
 * University of California, Santa Barbara (UCSB), with the Culler-Fried Interactive Mathematics Center's IBM 360/75, running OS/MVT being the machine attached;
 * A sketch of the ARPANET in December 1969.png University of Utah School of Computing, where Ivan Sutherland had moved, running a DEC PDP-10 operating on TENEX.

The first successful host-to-host connection on the ARPANET was made between Stanford Research Institute (SRI) and UCLA, by SRI programmer Bill Duvall and UCLA student programmer Charley Kline, at 10:30 pm PST on 29 October 1969 (6:30 UTC on 30 October 1969). Kline connected from UCLA's SDS Sigma 7 Host computer (in Boelter Hall room 3420) to the Stanford Research Institute's SDS 940 Host computer. Kline typed the command "login," but initially the SDS 940 crashed after he typed two characters. About an hour later, after Duvall adjusted parameters on the machine, Kline tried again and successfully logged in. Hence, the first two characters successfully transmitted over the ARPANET were "lo". The first permanent ARPANET link was established on 21 November 1969, between the IMP at UCLA and the IMP at the Stanford Research Institute. By 5 December 1969, the initial four-node network was established.

Elizabeth Feinler created the first Resource Handbook for ARPANET in 1969 which led to the development of the ARPANET directory. The directory, built by Feinler and a team made it possible to navigate the ARPANET.

Network performance
In 1968, Roberts contracted with Kleinrock to measure the performance of the network and find areas for improvement. Building on his earlier work on queueing theory and optimization of packet delay in communication networks, Kleinrock specified mathematical models of the performance of packet-switched networks, which underpinned the development of the ARPANET as it expanded rapidly in the early 1970s.

Growth and evolution
Roberts engaged Howard Frank to consult on the topological design of the network. Frank made recommendations to increase throughput and reduce costs in a scaled-up network. By March 1970, the ARPANET reached the East Coast of the United States, when an IMP at BBN in Cambridge, Massachusetts was connected to the network. Thereafter, the ARPANET grew: 9 IMPs by June 1970 and 13 IMPs by December 1970, then 18 by September 1971 (when the network included 23 university and government hosts); 29 IMPs by August 1972, and 40 by September 1973. By June 1974, there were 46 IMPs, and in July 1975, the network numbered 57 IMPs. By 1981, the number was 213 host computers, with another host connecting approximately every twenty days.

Support for inter-IMP circuits of up to 230.4 kbit/s was added in 1970, although considerations of cost and IMP processing power meant this capability was not actively used.

Larry Roberts saw the ARPANET and NPL projects as complementary and sought in 1970 to connect them via a satellite link. Peter Kirstein's research group at University College London (UCL) was subsequently chosen in 1971 in place of NPL for the UK connection. In June 1973, a transatlantic satellite link connected ARPANET to the Norwegian Seismic Array (NORSAR), via the Tanum Earth Station in Sweden, and onward via a terrestrial circuit to a TIP at UCL. UCL provided a gateway for interconnection of the ARPANET with British academic networks, the first international resource sharing network, and carried out some of the earliest experimental research work on internetworking.

1971 saw the start of the use of the non-ruggedized (and therefore significantly lighter) Honeywell 316 as an IMP. It could also be configured as a Terminal Interface Processor (TIP), which provided terminal server support for up to 63 ASCII serial terminals through a multi-line controller in place of one of the hosts. The 316 featured a greater degree of integration than the 516, which made it less expensive and easier to maintain. The 316 was configured with 40 kB of core memory for a TIP. The size of core memory was later increased, to 32 kB for the IMPs, and 56 kB for TIPs, in 1973.

The ARPANET was demonstrated at the International Conference on Computer Communications in October 1972.

In 1975, BBN introduced IMP software running on the Pluribus multi-processor. These appeared in a few sites. In 1981, BBN introduced IMP software running on its own C/30 processor product.

Operation
ARPA was intended to fund advanced research. The ARPANET was a research project that was communications-oriented, rather than user-oriented in design. Nonetheless, in the summer of 1975, operational control of the ARPANET passed to the Defense Communications Agency. At about this time, the first ARPANET encryption devices were deployed to support classified traffic.

The ARPANET Completion Report, written in 1978 and published in 1981 jointly by BBN and DARPA, concludes that:

"... it is somewhat fitting to end on the note that the ARPANET program has had a strong and direct feedback into the support and strength of computer science, from which the network, itself, sprang."

CSNET, expansion
Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET).

Adoption of TCP/IP
The transatlantic connectivity with NORSAR and UCL later evolved into the SATNET. The ARPANET, SATNET and PRNET were interconnected in 1977.

The DoD made TCP/IP the standard communication protocol for all military computer networking in 1980. NORSAR and University College London left the ARPANET and began using TCP/IP over SATNET in 1982.

On January 1, 1983, known as flag day, TCP/IP protocols became the standard for the ARPANET, replacing the earlier Network Control Protocol.

MILNET, phasing out
In September 1984 work was completed on restructuring the ARPANET giving U.S. military sites their own Military Network (MILNET) for unclassified defense department communications. Both networks carried unclassified information and were connected at a small number of controlled gateways which would allow total separation in the event of an emergency. MILNET was part of the Defense Data Network (DDN).

Separating the civil and military networks reduced the 113-node ARPANET by 68 nodes. After MILNET was split away, the ARPANET would continue to be used as an Internet backbone for researchers, but be slowly phased out.

Decommissioning
In 1985, the NSF funded the establishment of national supercomputing centers at several universities and provided network access and network interconnectivity with the NSFNET project in 1986. NSFNET became the Internet backbone for government agencies and universities.

The ARPANET project was formally decommissioned in 1990. The original IMPs and TIPs were phased out as the ARPANET was shut down after the introduction of the NSFNet, but some IMPs remained in service as late as July 1990.

In the wake of the decommissioning of the ARPANET on 28 February 1990, Vinton Cerf wrote the following lamentation, entitled "Requiem of the ARPANET":

"It was the first, and being first, was best,

but now we lay it down to ever rest.

Now pause with me a moment, shed some tears.

For auld lang syne, for love, for years and years

of faithful service, duty done, I weep.

Lay down thy packet, now, O friend, and sleep.

-Vinton Cerf"

Legacy

The technological advancements and practical applications achieved through the ARPANET were instrumental in shaping modern computer networking including the Internet. Development and implementation of the concepts of packet switching, decentralized networks, and communication protocols, notably TCP/IP, laid the foundation for a global network that revolutionized communication, information sharing and collaborative research across the world.

The ARPANET was related to many other research projects, which either influenced the ARPANET design, or which were ancillary projects or spun out of the ARPANET.

Senator Al Gore authored the High Performance Computing and Communication Act of 1991, commonly referred to as "The Gore Bill", after hearing the 1988 concept for a National Research Network submitted to Congress by a group chaired by Leonard Kleinrock. The bill was passed on 9 December 1991 and led to the National Information Infrastructure (NII) which Gore called the information superhighway.

The ARPANET project was honored with two IEEE Milestones, both dedicated in 2009.

IMP functionality
Because it was never a goal for the ARPANET to support IMPs from vendors other than BBN, the IMP-to-IMP protocol and message format were not standardized. However, the IMPs did nonetheless communicate amongst themselves to perform link-state routing, to do reliable forwarding of messages, and to provide remote monitoring and management functions to ARPANET's Network Control Center. Initially, each IMP had a 6-bit identifier and supported up to 4 hosts, which were identified with a 2-bit index. An ARPANET host address, therefore, consisted of both the port index on its IMP and the identifier of the IMP, which was written with either  notation or as a single byte; for example, the address of MIT-DMG (notable for hosting development of Zork) could be written as either   or. An upgrade in early 1976 extended the host and IMP numbering to 8-bit and 16-bit, respectively.

In addition to primary routing and forwarding responsibilities, the IMP ran several background programs, titled TTY, DEBUG, PARAMETER-CHANGE, DISCARD, TRACE, and STATISTICS. These were given host numbers in order to be addressed directly and provided functions independently of any connected host. For example, "TTY" allowed an on-site operator to send ARPANET packets manually via the teletype connected directly to the IMP.

1822 protocol
The starting point for host-to-host communication on the ARPANET in 1969 was the 1822 protocol, which defined the transmission of messages to an IMP. The message format was designed to work unambiguously with a broad range of computer architectures. An 1822 message essentially consisted of a message type, a numeric host address, and a data field. To send a data message to another host, the transmitting host formatted a data message containing the destination host's address and the data message being sent, and then transmitted the message through the 1822 hardware interface. The IMP then delivered the message to its destination address, either by delivering it to a locally connected host, or by delivering it to another IMP. When the message was ultimately delivered to the destination host, the receiving IMP would transmit a Ready for Next Message (RFNM) acknowledgment to the sending, host IMP.

Network Control Protocol
Unlike modern Internet datagrams, the ARPANET was designed to reliably transmit 1822 messages, and to inform the host computer when it loses a message; the contemporary IP is unreliable, whereas the TCP is reliable. Nonetheless, the 1822 protocol proved inadequate for handling multiple connections among different applications residing in a host computer. This problem was addressed with the Network Control Protocol (NCP), which provided a standard method to establish reliable, flow-controlled, bidirectional communications links among different processes in different host computers. The NCP interface allowed application software to connect across the ARPANET by implementing higher-level communication protocols, an early example of the protocol layering concept later incorporated in the OSI model.

NCP was developed under the leadership of Steve Crocker, then a graduate student at UCLA. Crocker created and led the Network Working Group (NWG) which was made up of a collection of graduate students at universities and research laboratories, including Jon Postel and Vint Cerf at UCLA. They were sponsored by ARPA to carry out the development of the ARPANET and the software for the host computers that supported applications.

Network applications
NCP provided a standard set of network services that could be shared by several applications running on a single host computer. This led to the evolution of application protocols that operated, more or less, independently of the underlying network service, and permitted independent advances in the underlying protocols.

The various application protocols such as TELNET for remote time-sharing access and File Transfer Protocol (FTP), the latter used to enable rudimentary electronic mail, were developed and eventually ported to run over the TCP/IP protocol suite. In the 1980s, FTP for email was replaced by the Simple Mail Transfer Protocol and, later, POP and IMAP.

Telnet was developed in 1969 beginning with RFC 15, extended in RFC 855.

The original specification for the File Transfer Protocol was written by Abhay Bhushan and published as on 16 April 1971. By 1973, the File Transfer Protocol (FTP) specification had been defined and implemented, enabling file transfers over the ARPANET.

In 1971, Ray Tomlinson, of BBN sent the first network e-mail. An ARPA study in 1973, a year after network e-mail was introduced to the ARPANET community, found that three-quarters of the traffic over the ARPANET consisted of email messages. E-mail remained a very large part of the overall ARPANET traffic.

The Network Voice Protocol (NVP) specifications were defined in 1977, and implemented. But, because of technical shortcomings, conference calls over the ARPANET never worked well; the contemporary Voice over Internet Protocol (packet voice) was decades away.

TCP/IP
Stephen J. Lukasik directed DARPA to focus on internetworking research in the early 1970s. Bob Kahn moved from BBN to DARPA in 1972, first as program manager for the ARPANET, under Larry Roberts, then as director of the IPTO when Roberts left to found Telenet. Kahn worked on both satellite packet networks and ground-based radio packet networks, and recognized the value of being able to communicate across both. Steve Crocker, now at DARPA, and the leaders of British and French network projects founded the International Network Working Group in 1972 and, on Crocker's recommendation, Vint Cerf, now on the faculty at Stanford University, became its Chair. This group considered how to interconnect packet switching networks with different specifications, that is, internetworking. Research led by Kahn and Cerf resulted in the formulation of the Transmission Control Program, which incorporated concepts from the French CYCLADES project directed by Louis Pouzin. Its specification was written by Cerf with Yogen Dalal and Carl Sunshine at Stanford in December 1974. The following year, testing began through concurrent implementations at Stanford, BBN and University College London. At first a monolithic design, the software was redesigned as a modular protocol stack in version 3 in 1978. Version 4 was installed in the ARPANET for production use in January 1983, replacing NCP. The development of the complete Internet protocol suite by 1989, as outlined in and, and partnerships with the telecommunication and computer industry laid the foundation for the adoption of TCP/IP as a comprehensive protocol suite as the core component of the emerging Internet.

Password protection
The Purdy Polynomial hash algorithm was developed for the ARPANET to protect passwords in 1971 at the request of Larry Roberts, head of ARPA at that time. It computed a polynomial of degree 224 + 17 modulo the 64-bit prime p = 264 − 59. The algorithm was later used by Digital Equipment Corporation (DEC) to hash passwords in the VMS operating system and is still being used for this purpose.

Rules and etiquette
Because of its government funding, certain forms of traffic were discouraged or prohibited.

Leonard Kleinrock claims to have committed the first illegal act on the Internet, having sent a request for return of his electric razor after a meeting in England in 1973. At the time, use of the ARPANET for personal reasons was unlawful.

In 1978, against the rules of the network, Gary Thuerk of Digital Equipment Corporation (DEC) sent out the first mass email to approximately 400 potential clients via the ARPANET. He claims that this resulted in $13 million worth of sales in DEC products, and highlighted the potential of email marketing.

A 1982 handbook on computing at MIT's AI Lab stated regarding network etiquette:

"It is considered illegal to use the ARPANet for anything which is not in direct support of Government business ... personal messages to other ARPANet subscribers (for example, to arrange a get-together or check and say a friendly hello) are generally not considered harmful ... Sending electronic mail over the ARPANet for commercial profit or political purposes is both anti-social and illegal. By sending such messages, you can offend many people, and it is possible to get MIT in serious trouble with the Government agencies which manage the ARPANet."

In popular culture

 * Computer Networks: The Heralds of Resource Sharing, a 30-minute documentary film featuring Fernando J. Corbató, J. C. R. Licklider, Lawrence G. Roberts, Robert Kahn, Frank Heart, William R. Sutherland, Richard W. Watson, John R. Pasta, Donald W. Davies, and economist, George W. Mitchell.
 * "Scenario", an episode of the U.S. television sitcom Benson (season 6, episode 20—dated February 1985), was the first incidence of a popular TV show directly referencing the Internet or its progenitors. The show includes a scene in which the ARPANET is accessed.
 * There is an electronic music artist known as "Arpanet", Gerald Donald, one of the members of Drexciya. The artist's 2002 album Wireless Internet features commentary on the expansion of the internet via wireless communication, with songs such as NTT DoCoMo, dedicated to the mobile communications giant based in Japan.
 * Thomas Pynchon mentions the ARPANET in his 2009 novel Inherent Vice, which is set in Los Angeles in 1970, and in his 2013 novel Bleeding Edge.
 * The 1993 television series The X-Files featured the ARPANET in a season 5 episode, titled "Unusual Suspects". John Fitzgerald Byers offers to help Susan Modeski (known as Holly ... "just like the sugar") by hacking into the ARPANET to obtain sensitive information.
 * In the spy-drama television series The Americans, a Russian scientist defector offers access to ARPANET to the Russians in a plea to not be repatriated (Season 2 Episode 5 "The Deal"). Episode 7 of Season 2 is named 'ARPANET' and features Russian infiltration to bug the network.
 * In the television series Person of Interest, main character Harold Finch hacked the ARPANET in 1980 using a homemade computer during his first efforts to build a prototype of the Machine. This corresponds with the real life virus that occurred in October of that year that temporarily halted ARPANET functions. The ARPANET hack was first discussed in the episode 2PiR (stylised 2$\pi$R) where a computer science teacher called it the most famous hack in history and one that was never solved. Finch later mentioned it to Person of Interest Caleb Phipps and his role was first indicated when he showed knowledge that it was done by "a kid with a homemade computer" which Phipps, who had researched the hack, had never heard before.
 * In the third season of the television series Halt and Catch Fire, the character Joe MacMillan explores the potential commercialization of the ARPANET.

Oral histories

 * Focuses on Kahn's role in the development of computer networking from 1967 through the early 1980s. Beginning with his work at BBN, Kahn discusses his involvement as the ARPANET proposal was being written and then implemented, and his role in the public demonstration of the ARPANET. The interview continues into Kahn's involvement with networking when he moves to IPTO in 1972, where he was responsible for the administrative and technical evolution of the ARPANET, including programs in packet radio, the development of a new network protocol (TCP/IP), and the switch to TCP/IP to connect multiple networks.
 * Cerf describes his involvement with the ARPA network, and his relationships with Bolt Beranek and Newman, Robert Kahn, Lawrence Roberts, and the Network Working Group.
 * Baran describes his work at RAND, and discusses his interaction with the group at ARPA who were responsible for the later development of the ARPANET.
 * Kleinrock discusses his work on the ARPANET.
 * Lukasik discusses his tenure at the Advanced Research Projects Agency (ARPA), the development of computer networks and the ARPANET.
 * Frank describes his work on the ARPANET, including his interaction with Roberts and the IPT Office.
 * Frank describes his work on the ARPANET, including his interaction with Roberts and the IPT Office.

Detailed technical reference works

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title: ARPANET


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Fancy Lala

Fancy Lala, known in Japan as Fancy Lala, the Magic Stage (魔法のステージ・ファンシーララ), is a magical girl anime series produced by Studio Pierrot in 1998, following an OVA released in 1988. A two-volume manga adaptation by Rurika Kasuga ran in Ribon. The original designs were created by Akemi Takada, who worked on many of the 80s' Studio Pierrot series. The anime series was licensed for English release by Bandai Entertainment with a dub produced in Calgary and Edmonton, Alberta, Canada by Blue Water Studios which was owned by Ocean Productions in Vancouver. This was the last magical girl anime Pierrot has produced until Tokyo Mew Mew in 2002.

Plot summary
One day, a 9-year-old elementary schoolgirl named Miho Shinohara is given two stuffed dinosaurs by an unnamed stranger. The stuffed dinosaurs come to life and they present her with a magic sketchbook and pen. Within limits, and subject to varying degrees of control, she can draw in the sketchbook and bring the drawings to life. Miho can also transform into a teenage girl, whom she names Fancy Lala. One day, Lala is scouted by Yumi Haneishi, the president of the talent agency Lyrical Productions, and begins the long road to stardom.

Main cast

 * Miho Shinohara (篠原 みほ) / Fancy Lala (ファンシーララ)
 * A 9-year-old elementary school girl, Miho dreams of one day drawing manga as a career. After Mystery Man gives her Pigu and Mogu, they in turn give her a magical pen and sketchbook, which allow her to transform into the body of a 15-year-old girl who she names Fancy Lala. Fancy Lala is scouted by Yumi Haneishi of Lyrical Productions, and gradually follows the path to stardom though her parents nor sister knows about this.
 * A 9-year-old elementary school girl, Miho dreams of one day drawing manga as a career. After Mystery Man gives her Pigu and Mogu, they in turn give her a magical pen and sketchbook, which allow her to transform into the body of a 15-year-old girl who she names Fancy Lala. Fancy Lala is scouted by Yumi Haneishi of Lyrical Productions, and gradually follows the path to stardom though her parents nor sister knows about this.

 * Mog (モグ)
 * Voiced by: Michiko Neya (Japanese), Chris Simms (English)
 * A small pink dinosaur who accompanies Miho Shinohara. Mog is a girl.

 * Pog (ピグ)
 * A small blue dinosaur who accompanies Miho Shinohara. Pog is a boy.
 * A small blue dinosaur who accompanies Miho Shinohara. Pog is a boy.

 * Mystery Man (不思議さん)
 * A mysterious person who gave Miho Shinohara Pigu and Mogu. He often advises Miho/Fancy Lala; his name is never mentioned in the series.
 * A mysterious person who gave Miho Shinohara Pigu and Mogu. He often advises Miho/Fancy Lala; his name is never mentioned in the series.

 * Hiroya Aikawa (相川 ひろや)
 * A popular idol who happens to be very attractive, Hiroya is Miho Shinohara's love-interest, and Fancy Lala's mentor at Lyrical Productions.
 * A popular idol who happens to be very attractive, Hiroya is Miho Shinohara's love-interest, and Fancy Lala's mentor at Lyrical Productions.

 * Yumi Haneishi (羽根石 由美)
 * The president of Lyrical Productions, who represent Fancy Lala. She was once married to Kishi, the guitarist of Hiroya Aikawa's band but the two ended up getting divorced, and has a son named Tappei, who attends kindergarten.
 * The president of Lyrical Productions, who represent Fancy Lala. She was once married to Kishi, the guitarist of Hiroya Aikawa's band but the two ended up getting divorced, and has a son named Tappei, who attends kindergarten.

 * Ririka Kawaguchi (川口 理々香)
 * (Japanese)
 * An employee at Lyrical Productions, and Fancy Lala's manager.

 * Taro Yoshida (吉田 太郎)
 * Miho's classmate and next door neighbor, they often fight (often like an old married couple), but he cares about her deeply. He is also the cousin of Miki Yumeno. He seems to have a romantic interest in Miho, however he doesn't know that Miho has a crush on Hiroya.
 * Miho's classmate and next door neighbor, they often fight (often like an old married couple), but he cares about her deeply. He is also the cousin of Miki Yumeno. He seems to have a romantic interest in Miho, however he doesn't know that Miho has a crush on Hiroya.

 * Miki Yumeno (夢野 美樹)
 * A popular idol, Miki is Fancy Lala's main rival. She is also the cousin of Taro Yoshida, Miho's male classmate from school.
 * A popular idol, Miki is Fancy Lala's main rival. She is also the cousin of Taro Yoshida, Miho's male classmate from school.

Supporting cast

 * Katsunoshin Asaka (朝霞 勝之進)
 * Miho Shinohara's teacher.
 * Miho Shinohara's teacher.

 * Emiko Kanno (菅野 江美子)
 * An employee at Lyrical Productions.
 * An employee at Lyrical Productions.

 * Komiyama (コミさん)
 * Komiyama is Fancy Lala's stylist. It is hinted in the last episode that he knows more about what is going on than meets the eye.
 * Komiyama is Fancy Lala's stylist. It is hinted in the last episode that he knows more about what is going on than meets the eye.

 * Anna Nozaki (野崎 あんな)
 * (Japanese)
 * A classmate of Miho Shinohara.

 * Chisa Shinohara (篠原 ちさ)
 * Miho Shinohara's older sister. She's also a freshman in high school and her uniform consists of a white sailor collared shirt with a green collar, a red ribbon and a grey pleated skirt.
 * Miho Shinohara's older sister. She's also a freshman in high school and her uniform consists of a white sailor collared shirt with a green collar, a red ribbon and a grey pleated skirt.

 * Mamiko Shinohara (篠原 真実子)
 * Miho Shinohara's mother, she works as a TV producer, and is often away from home.
 * Miho Shinohara's mother, she works as a TV producer, and is often away from home.

 * Yoichiro Shinohara (篠原 洋一郎)
 * Miho Shinohara's father, he works as a paleontologist, and mostly works at home.
 * Miho Shinohara's father, he works as a paleontologist, and mostly works at home.

 * Yoshio (ヨシオ)
 * An employee at Lyrical Productions.
 * An employee at Lyrical Productions.

 * Akiru Yuki (結城 あきる)
 * Miho Shinohara's classmate, and closest friend, she dreams of becoming an actress.
 * Miho Shinohara's classmate, and closest friend, she dreams of becoming an actress.

Production
Fancy Lala is a complete remake of an earlier Studio Pierrot OVA titled Harbor Light Story Fashion Lala Yori. It was also influenced by Mahō no Tenshi Creamy Mami, the story of a ten-year-old Japanese girl granted the power to transform who also became an idol.

Harbor Light Story Fashion Lala Yori
The original OVA was very different than the final series, being a retelling of Cinderella. In it, the heroine, Miho, a little girl who dreams of being a fashion designer, lives with her aunt and three cousins while her father is away on business. The aunt, who runs a dress shop, exploits Miho's dependence and makes her perform deliveries on her bike, while spoiling her own daughters. Of the three, the two oldest are cruel and mock Miho's dreams, but the youngest is nice to her. A local disco is holding a contest to find the next "Disco Queen." Miho is too young to enter, but decides to design a dress for her cousin. When the aunt finds out, she rips up the dress. After everyone leaves, two fairies take pity on Miho and transform her into "Fashion Lala," a sixteen-year-old blonde, so she can enter the contest herself. While performing, Miho's outfit changes into her previous designs, and it seems that she wins. At the end, she returns to a happy life with her father and her two oldest cousins apologized to Miho for being cruel to her and mocking her dreams for no reason.

The heroine being named Miho and the two fairies, as well as the concept of an "evil cousin", were the only things retained for the final series.

Internationalization
Fancy Lala was licensed by Bandai Entertainment for English release in 2001, and dubbed at Blue Water Studios. The series has been released on DVD, but is only distributed in region 1 outside Japan.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Fancy Lala


text:
Talk:Blondie (band)

Old text
What does "re-invented themselves at every turn" mean?

 * In the context of the 80s self-re-invention has a lot to do with hair mousse. Actually, the author probably meant something about introducing mainstream audiences to ska (tide is high) and rap (man from mars), etc., etc. --MichaelTinkler (who really loved the 80s - don't get him wrong).

Loved the band in their early days--even saw a free concert in '80s. Still, shouldn't this be a disambiguation page to the comic strip and spin off TV series? Danny

Is there an article about the comic strip anywhere? -- Zoe

Infante sues
I took out the following from the main text: "Frank Infante sued the band regarding a lack of involvement during the Autoamerican sessions; it was settled out of court, and Infante remained in the band (though Harry has subsequently said Infante was not on the next LP, despite appearing on the front cover)."

It lacks a reference. I tried to find one but I am wondering if anyone has come across one. I suppose it is a possible BLP issue. Karst (talk) 23:12, 14 December 2022 (UTC)
 * There is a paragraph in chapter 13 of Harry's memoir Face It:
 * After we decided not to ask Frank Infante and Nigel Harrison to join the reunion, they took a lawsuit out against us. Even though they weren’t going to be working with the band, they took us to court to sue us for potential future income. But the state of New York found in our favor. And the reconstituted Blondie got back to work with Leigh Foxx and Paul Carbonara joining myself, Chris, Clem, and Jimmy.
 * It resulted in a later incident at Blondie's induction into the Rock and Roll Hall of Fame, described in chapter 14, when Infante and Harrison wanted to perform on stage at the induction. It seems significant enough to want to include in the article. 2601:648:8200:990:0:0:0:B68B (talk) 04:14, 17 March 2023 (UTC)

 * Yes, this refers to the 1997 reunion. However, the section I took out concerns an earlier possible lawsuit in 1980 around the time of the recording of the Autoamerican album. Karst (talk) 15:25, 19 March 2023 (UTC)

Deborah Harry
She has used the name Deborah rather than Debbie since 1998 per Debbie Harry discography, but this article consistently refers to her as Debbie. I don't remember her biography saying anything about this and will try to check. I've always heard her referred to as Deborah (which sounds better, imho) so the usage of Debbie jumped out at me. I wasn't paying attention pre-1998 though. 2601:648:8200:990:0:0:0:B68B (talk) 01:19, 14 March 2023 (UTC)
 * Ah, nm. I looked at blondie.net etc. and it really does say Debbie almost everywhere.  I never paid attention to this band in the past but have been listening to some of their songs lately, so noticing this stuff more. 2601:648:8200:990:0:0:0:B68B (talk) 19:59, 14 March 2023 (UTC)
 * We refer to her as Harry per WP:LASTNAME. "Debbie Harry" is her professional name, so Deborah is not appropriate here. Binksternet (talk) 21:39, 14 March 2023 (UTC)
 * I believe you but I'm having trouble sourcing it, at least with a bit of web searching. Cathay Che's 2013 biography "Deborah Harry, Platinum Blonde" doesn't seem to say anything about this, but it says Deborah in the title and refers to her both ways in the text.  A TCM biography says she was billed as Deborah in her movie acting career.  However, the poster for Hairspray (1988 film) says Debbie while the poster and DVD cover for Heavy (film) (1995) both say Deborah.  Her first and second solo albums Rockbird (1986) and Once More into the Bleach (1988) say Debbie on the cover while Def, Dumb & Blonde (1989) and The Complete Picture: The Very Best of Deborah Harry and Blondie (1991) both say Deborah.   I haven't looked at the rest, but this is consistent with the claim of a 1988 changeover.  OTOH, Harry's 2019 memoir "Face It" says Debbie on the cover (I haven't looked at the text).  deborahharry.com is currently domain squatted, deborahharry.net is non responsive, debbieharry.net is an archivist page that hasn't been updated in quite a while, and debbieharry.com is an "official" page that funnels through a video that my browser doesn't render.  Anyway it seems like something to look further into, or maybe someone can ask her. 2601:648:8200:990:0:0:0:B68B (talk) 19:47, 16 March 2023 (UTC)
 * Ok, from chapter 12 ("The Perfect Taste") of Face It:
 * Def, Dumb and Blonde was released that same year. The name on the front sleeve was “Deborah Harry.” I had started to feel pretty strongly about differentiating between Blondie and the solo projects, and that was one simple way of doing it. Plus, I had come to the point where I thought that Deborah was a prettier-sounding name than Debbie.
 * I feel enlightened now. 2601:648:8200:990:0:0:0:B68B (talk) 02:24, 17 March 2023 (UTC)
 * Far Out adds:
 * Supporting her fourth studio album as a solo artist, the Blondie singer reverted her stage name back to Deborah and was clearly trying to show the variety of her talent. She wasn’t just a frontwoman, a pop star or a punk pioneer, she was Deborah fucking Harry and it was about time everybody knew it. The tour was such a success that they had planned to make it a live album but that never came to fruition. Luckily, we still have this gem floating around as bootleg.
 * This stuff should probaby be mentioned in Harry's biography article. It's less relevant to the article about Blondie, but here we are.  I may edit that article tomorrow, or post a talk comment.  If not, maybe someone else can do it.  There is no need to wait up for me if you can get to it first. 2601:648:8200:990:0:0:0:B68B (talk) 08:47, 17 March 2023 (UTC)

The Debbie_Harry article says "In 1981, Harry issued a press release to clarify that her name was not "Debbie Blondie" or "Debbie Harry" but rather Deborah Harry..."

It also says "Her next solo venture was the album Def, Dumb and Blonde in 1989. At this point Harry reverted from "Debbie" to "Deborah" as her professional name."

title: Talk:Blondie (band)


text:
San Francisco Municipal Railway

The San Francisco Municipal Railway (SF Muni or Muni), is the primary public transit system within San Francisco, California. It operates a system of bus routes (including trolleybuses), the Muni Metro light rail system, three historic cable car lines, and two historic streetcar lines. Previously an independent agency, the San Francisco Municipal Railway merged with two other agencies in 1999 to become the San Francisco Municipal Transportation Agency (SFMTA). In 2018, Muni served 46.7 sqmi with an operating budget of about $1.2 billion. Muni is the seventh-highest-ridership transit system in the United States, with rides in, and the second-highest in California after the Los Angeles County Metropolitan Transportation Authority.

Operations

Most bus lines are scheduled to operate every five to fifteen minutes during peak hours, every five to twenty minutes middays, about every ten to twenty minutes from 9 pm to midnight, and roughly every half-hour for the late night "owl" routes. On weekends, most Muni bus lines are scheduled to run every ten to twenty minutes. However, complaints of unreliability, especially on less-often-served lines and older (pre-battery backup) trolleybus lines, are a system-wide problem. Muni has had some difficulty meeting a stated goal of 85% voter-demanded on-time service.

All Muni lines run inside San Francisco city limits, with the exception of several lines serving locations in the northern part of neighboring Daly City, and the 76X Marin Headlands Express line to the Marin Headlands area on weekends and major holidays. Most intercity connections are provided by BART and Caltrain heavy rail, AC Transit buses at the Transbay Transit Center, and Golden Gate Transit and SamTrans downtown.

Bus and car stops throughout the city vary from Metro stations with raised platforms in the subway and at the more heavily used surface stops, to small shelters to signposts to simply a yellow stripe on a utility pole or on the road surface. 70% of stops are spaced closer than recommended range of 800 – apart.

Name and logo
Muni is short for the "Municipal" in "San Francisco Municipal Railway" and is not an acronym; thus, when it is written in plain text, only Muni (not MUNI) is correct. The Muni metro is often called "the train" or "the streetcar." Most San Franciscans use 'Muni' when speaking about the system (Metro & buses) in general.

The E Embarcadero and F Market & Wharves lines are referred to by Muni as a "historic streetcar line" rather than as a "heritage railway."

Muni's logo is a stylized, trademarked "worm" version of the word muni. This logo was designed by San Francisco-based graphic designer Walter Landor in the mid-1970s.

Announcements
To cater to the large Hispanic and Latino American and Asian American populations in San Francisco, bus announcements are in four languages: English, Spanish, Cantonese and Tagalog.

Route names
Bus and trolleybus lines have number designations, rail lines have letters and the three cable car lines are typically referred to by name only (Powell-Mason, Powell-Hyde and California).

Fares
Except for cable cars, cash fares are $3.00 for adults; $1.50 for seniors over 65, people with disabilities, and Medicare card holders; and free for low- and moderate-income seniors, youth aged 5–18, people with disabilities residing in San Francisco, and up to three kids under 5 per adult. Clipper card and MuniMobile fares are $2.50 for adults and $1.25 for seniors, youth, and people with disabilities. Proof-of-payment, which fare inspectors may demand at any time, is either a Clipper card, MuniMobile, Muni Passport, or paper transfer. One fare entitles a rider to unlimited vehicle transfers for the next 120 minutes. Cable cars are $8 one way, with no transfers, unless the rider has a Muni Passport or a Muni monthly pass. As of July 2019 monthly passes cost $81 for adults ($98 with BART privileges within city limits), $40 for low-income residents ("Life Line Pass"), or $40 for youth, seniors and the disabled. Passes are valid on all Muni lines—including cable cars—and the $98 adult pass allows BART transit entirely within San Francisco (between Embarcadero and Balboa Park). Other passes and stickers are valid on all Muni lines, including cable cars, but not on BART (with the exception of BART-Plus ticket types).

Cable car fare is $8 per trip, with no transfers issued or accepted. "Passports" are folding scratch-off passes that can be purchased by mail, or at various places throughout the city; they are good on all regular-service lines without surcharge, including cable cars. As of September 2018, Passports cost $23 for a 1-day pass, $34 for a 3-day pass, or $45 for a 7-day pass, with discounts for using Clipper card or MuniMobile.

Muni has implemented a dual-mode smart card payment system known as Clipper (formerly TransLink). The transponders have been in use since at least 2004, and replaced most paper monthly passes in 2010. BART, Caltrain, Golden Gate Transit, VTA, AC Transit, SamTrans, SMART and San Francisco Bay Ferry also utilize the Clipper system.

Fares can also be paid with a mobile app called MuniMobile since 2015. The app is developed by moovel, who have built mobile ticketing apps for a number of other transit agencies such as Caltrain and TriMet. The app is planned to be deployed until around 2021 when the next generation Clipper card mobile app is planned to launch and replace agency-specific ticketing apps.

Special service
Muni operates 14 express lines, 5 Rapid lines, and 12 Owl lines, which run between 1 am and 5 am. For San Francisco Giants games, additional "baseball shuttles" supplement N Judah and T Third service to Oracle Park.

Express lines only run during peak hours; during mornings they run towards downtown (the Financial District) and during the evening they run away from downtown. All express lines have an "X", "AX", or "BX" following the line's number. Some lines are divided into A and B Expresses. The B Express line is shorter and has stops that are closer to downtown, while the A Express makes stops further away from downtown and will make few or no stops in the area where the B Express stops. The 8 Bayshore, as the 8X Bayshore Express, was the only Express route that ran daily until April 25, 2015, the date when it was no longer an Express route.

Rapid lines (having an R following their route number) are limited-stop services. They stop at only a subset of the stops of their corresponding "standard" line—typically every third stop and at transfer points.

Cable car system
Muni also operates the San Francisco cable car system, a heritage streetcar system descendant of a larger network of manually operated cable cars. The first city-owned line was acquired in 1906, although the current configuration is an amalgamation of several former lines and has operated as such since in 1952. The system was designated a National Historic Landmark in 1964 and placed on the National Register of Historic Places in 1966. There are three cable car lines being the Mason-Powell line, the California State line, and the Powell- Hyde line. Popular areas from the Embarcadero to Fisherman's Wharf are served by cable cars. In the system, there are 62 allocated stations. The system accrues five million annual riders and has always been a tourist destination as well as a convenient means for travel around the city.

Heritage streetcars
Additionally, Muni operates two heritage streetcar lines distinct from the Muni Metro: the E Embarcadero and F Market & Wharves, however the former has been suspended since April 2020 due to the COVID-19 pandemic. Formerly run for the Historic Trolley Festival, in the 1980s, regular service of heritage equipment began in 1995. Streetcars do not utilize tunnel segments and the F line utilizes infrastructure optimized for trolleybuses along Market Street (the former routing of all downtown streetcar lines before the formation of Muni Metro).

Statistics
The longest Muni line is the 24.1 mi a nighttime-only route that blends several other routes together, while the longest daytime route is the 17.4 mi. The shortest route is the peak-hour only at 1.4 mi, while the shortest off-peak route is the  at 1.6 mi. The steepest grade climbed by Muni vehicle is 23.1% by a diesel-electric hybrid bus on the  line, 22.8% by a trolleybus on the  line and 21% by a cable car on the Powell-Hyde line.

The busiest Muni bus corridor is the Geary corridor. The two major routes that operate on the corridor, the and, travel 6.5 mi in the east–west direction along the Geary corridor, and has an average speed of only 8 mph, taking over 50 minutes to travel from the Richmond District to the Transbay Terminal when operating on schedule. As of 2015, the corridor has a total of 55,270 average daily boardings, making it the second busiest transit corridor west of the Mississippi after the Los Angeles Metro Wilshire transit corridor.

At Powell and Market Streets and California and Market Streets, three types of rail gauges come within a few hundred feet of each other: Bay Area Rapid Transit's broad gauge (which is underground in the lower level of the Market Street subway), Muni Metro's  (also underground in the upper level of the subway), and the San Francisco cable car system's  narrow gauge (at street level a few hundred feet away to the north of Market Street in both cases). The F Market and Wharves, a heritage streetcar line, which is also standard gauge, is also present here, at street level on Market Street. The rail lines, however, do not physically intersect.

Fleet
Muni operates about 1,200 vehicles: 550 diesel-electric hybrid buses, 300 electric trolleybuses, 250 modern light rail vehicles, 50 historic streetcars and 40 cable cars. All vehicles, except for cable cars, are wheelchair accessible.

The electricity to run all of Muni's trolleybuses, light rail vehicles, streetcars, and the cable car powerhouse comes from the hydroelectric dam at the Hetch Hetchy Reservoir in Yosemite National Park.

All of Muni's current internal combustion buses use diesel-electric hybrid powertrains, fueled with renewable diesel fuel made from bio-feedstock sources, including fats, oils and greases. The combination of hybrid technology and renewable diesel fuel helps reduce fuel consumption and cut vehicle emissions.

Performance
In November 1999 San Francisco voters passed Proposition E setting standards for performance of having at least an 85% on-time record In July 2012 Muni vehicles were on-time 60% of the time and in August 2012, they were on-time 57% of the time. A report conducted by the San Francisco Municipal Transport Agency in early 2013 noted that Muni was on time only 58% of the time. It delayed its customers a total of 172,195 hours and reduced the city's economic activity by US$50 million per year. In 2013 the performance hit an all-time low of 57%, the on-time performance improved to 60% in January 2014, 60% in February 2014, and 60% in March 2014.

Muni Metro on-time performance as of June 2022:

Governance
Since the passage of Proposition E in November 1999, Muni has been part of the San Francisco Municipal Transportation Agency (SFMTA), a semi-independent city agency created by that ballot measure. The agency, into which Muni, the Department of Parking and Traffic, and the Taxicab Commission were merged, is governed by a seven-member Board of Directors appointed by the Mayor and confirmed by the Board of Supervisors. The acting Director of Transportation of the SFMTA since August 15, 2019 has been Thomas Maguire, appointed by the SFMTA Board as the interim replacement for Director of Transportation Edward Reiskin. On April 29, 2019, Director Reiskin announced that he would step down at the end of his contract in August 2019. On November 13, 2019, the agency announced that Jeffrey Tumlin would take over as the new director on December 16, 2019.

The day-to-day operations of Muni are overseen by the Transit division of the SFMTA, which is currently headed by Director of Transit Julie Kirschbaum.

Early years
Muni has its origins in the period following the 1906 San Francisco earthquake. Until then the city had been served by a number of commercial horsecar, cable car and electric streetcar operators. Many of these had been amalgamated into the United Railroads of San Francisco (URR) company. In 1909, voters approved a municipal rail line down Geary. Three years later in 1912, the city declined to renew the franchise that bestowed cable car operator Geary Street, Park & Ocean Railway the privilege of operating on Geary Street, and converted the line into a municipal electric streetcar line, the first line of Muni. In 1912, the average speed of the city's public transit was approximately 8.5 miles per hour – slightly faster than the average speed of 8.1 in 2007.

Muni soon started on a large building program. On December 29, 1914, the new Stockton Street Tunnel under Nob Hill opened, allowing streetcars from downtown to go to North Beach and the new Marina District. On February 3, 1918, the Twin Peaks Tunnel opened, making the southwestern quarter of the city available for development. On October 21, 1928, the Sunset Tunnel opened, bringing the N Judah streetcar line to the Sunset District. These improvements plunged Muni into direct competition with the URR on the entire length of Market Street. The two operators each operated its own pair of tracks down that thoroughfare, which came to be known as the "roar of the four".

1940s: The first trolleybuses
In 1941, Muni introduced its first trolleybus line, the R-Howard line. Trolleybuses had been running in San Francisco since 1935, but operated only by the Market Street Railway Company (MSRy), successor to the URR. By 1944, the MSR was in financial difficulties. Thus, at 5 am on September 29, 1944, Muni acquired its commercial competitor. Along with the routes and equipment, Muni adopted its competitor's more expensive seven-cent fare. Following national trends, Muni replaced most of its rail lines with trolleybus service in the succeeding decades. A few lines with dedicated rights-of-way (including those serving the Twin Peaks and Sunset tunnels) continued as rail lines running 1940s-era PCC streetcars through the 1970s. These lines became the foundation of the Muni Metro.

During World War II, because male employees had been called to serve in the military, both MSRy and Muni hired female 'motorettes' and conductors, including poet and author Maya Angelou in 1943.

1970s and 1980s: Construction and reorganization

In the 1950s and 1960s, the regional BART system was conceived as a much more extensive system than was eventually built, with plans for express trains through San Francisco and local service within San Francisco. Because it was assumed BART would provide local rail service, investment in Muni infrastructure failed to keep pace with major urban redevelopment projects. For example, BART was intended to provide Richmond district and Western Addition service as part of its Golden Gate Bridge/Marin line. This leaves a legacy of the inadequate 38-Geary bus serving these neighborhoods.

Construction on BART's Market street tunnel started in 1967, with two decks tracks – the upper intended to provide local service. Major cost overruns in the BART project forced the state legislature to rescue the project in 1969: curtailing local service in San Francisco and converting the partially constructed stations into the basis of a new light-rail subway called the Muni Metro to connect the downtown stations to the Twin Peaks Tunnel and continuing along reserved tracks to St. Francis Circle. Construction on the metro began in 1970, but the project suffered from further cuts and design changes throughout the 1970s. The Muni Metro finally opened in February 1980, for one line (N-Judah), with other lines following later in 1980, but the many design compromises and piecemeal planning led to long-term operational challenges and inefficiencies.

In 1970, Muni also suffered a severe diesel bus crisis.

Muni experienced a diesel bus availability crisis in 1981–1982 when most of their diesel buses, 401 GMC and Flxible "New Looks" purchases in 1969, reached the end of their 12-year design life and funds for their replacement were not available. Most of the rest of the fleet were undersized 36-foot AM Generals purchased for neighborhood routes, and their use on heavier lines exacerbated conditions. The trolley bus fleet was in good order and had excess capacity at the time so Muni improvised a few temporary services with them to help out. One such service was a trolley 14-Limited that used the abandoned trolley overhead on South Van Ness. The diesel 82-Chinatown was replaced with short runs of the 30-Stockton. But the trolleys could only go where their wires went.

Muni adopted some policies to alleviate future service issues due to an aged fleet. They would stagger bus purchases so not as large a portion of the fleet would hit retirement age at once. They would arrange for mid-life rebuilds to keep the buses more serviceable in their final years. And they would work to reduce the role of diesels in the total operation. Three trunk diesel lines were converted to trolley bus service in the next twelve years.

But these efforts have not been as successful as hoped. Out of necessity most of the fleet, 330 standard bus equivalents out of 506, were replaced in just two years in 1985–1986. (Standard bus equivalents factor the 30-foot and 60-foot into their equivalent capacity in 40-foot buses). And seven years passed without any new buses coming on board before Muni started its next full diesel fleet replacement cycle in 1999. This was fourteen years after the previous cycle instead of the twelve years that buses are designed to last. Muni is now aware that they must expect to keep diesel buses past their design life and have also found that funds granted for mid-life rebuilds require that the buses be kept longer still. As the fleet replacement cycle begins again in 2013, Muni has arranged for life-extending rebuilds of 142 buses, by count over 30% of the fleet.

In September 1982, the cable car system was shut down for 21 months for rebuilding, and there were massive line reorganizations as Muni restructured their route network to provide stronger cross-town services.

In 1983, Muni temporarily ran streetcars down Market Street as part of the San Francisco Historic Trolley Festival, initially conceived of as a substitute attraction for tourists during the one summer when no cable cars would be in operation. The service became so popular that the festival was repeated for several years following. Anticipating the return of permanent streetcar service on Market Street, Muni began rehabilitating tracks in 1987, a process that culminated in the opening of the F line in 1995.

The first modern Muni shelter was installed in front of the War Memorial Opera House in 1987.

1990s: the "Muni Meltdown"
The F line was reintroduced in 1995 as a heritage streetcar service. Initially designed as a temporary tourist attraction to make up for the suspension of cable car service for rebuilding, the F has become a permanent fixture. E line service, initially known as the Muni Metro Extension, started in January 1998 initially as a shuttle between Embarcadero station and Caltrain's 4th and Townsend station.

In June 1995, the San Francisco County Transportation Authority released The Four Corridor Plan, a vision to extend Muni Metro service along four major routes in the city: Bayshore (north-south along Third from the county line to California), Geary (east-west along Geary from 48th to Market/Kearny), North Beach (extending the new north-south Bayshore line along Kearny and Columbus to Fisherman's Wharf), and Van Ness (north-south along Van Ness from 16th and Mission to Aquatic Park), with a connector downtown to transfer between the Bayshore, Geary, and North Beach corridors. These have since been implemented as a combination of light rail (T Third and Central Subway) and bus rapid transit (Geary and Van Ness) services.

During the late 1990s, with aging equipment and poor management, Muni developed a reputation for poor and erratic service. In 1996 a group called Rescue Muni representing transit riders formed to organize concerns and press for change, advocating for the successful 1999 Proposition E that formed the San Francisco Municipal Transportation Agency and set service standards for Muni. In August 1998, San Francisco residents witnessed a protracted malfunction of Muni Metro after switching to an automatic train control implemented by Alcatel Transport Automation, culminating in an event that is now known as the Muni Meltdown.

Automatic control of Muni Metro light rail vehicles began on Saturday, August 22, three years behind schedule and at a cost of $70 million, three times the original estimate. Riders angry over delays confronted one driver during the Monday afternoon commute on August 24; he responded by locking himself in the driver's compartment and refused to move the train, halting all service for half an hour. Otherwise, no delays were attributable to the new automatic control system that Monday. However, by August 26, Mayor Willie Brown was threatening to sue Alcatel. Alcatel and Muni instead blamed delays on malfunctioning train cars. In addition, a proof-of-payment fare enforcement system went into effect that week, compounding rider confusion. Finally, riders who had previously been able to secure a seat by riding in the opposite direction (outbound) to Embarcadero station were forced to disembark there because of the E/Muni Metro Extension service that had begun in January; these changes and the delays frustrated many commuters. On Friday, August 28, 67 of the 131 LRVs (55 Boeing and 12 Breda) in the Muni Metro fleet were out of service for the morning commute; Mayor Brown personally rode from Civic Center to Embarcadero in the afternoon to experience the chaos for himself. Muni riders abandoned the underground system for carpools, taxis, buses, and F-Market streetcars after LRVs were delayed and stopped with no communication as to when they would resume service; transit times from 4th and Irving to Powell swelled to 120 minutes.

On August 31, two San Francisco Chronicle reporters staged a 1+1/2 mi race: one took the train, and the other walked along Market from Civic Center to Embarcadero. The two reporters tied as both completed their trips in 23 minutes; this was an improvement compared to the previous week, at the height of the Meltdown, when the same trip on Muni Metro could take three times as long. Mayor Brown re-enacted the race as the pedestrian on September 3; this time, Muni Metro service had improved and train passengers completed the trip in just seven minutes. At the request of the San Francisco Examiner, a member of the executive committee for Rescue Muni tracked the length of each ride on her eight-stop daily commute to the Financial District from the Sunset that week. Four of the ten trips took longer than 40 minutes, and the best time was 15 minutes.

By the third week of operation under automatic train control, the Muni Meltdown had passed and service was uneventful, albeit with fewer LRVs than normal and with drivers onboard each train. Muni officials apologized for the rough transition and promised to continue to improve service; privately they called the Meltdown "the biggest fiasco in the railway's history."

In an effort to improve service, Muni began to replace its troublesome fleet of Boeing-Vertol light rail vehicles with newer Italian Breda light rail vehicles in late 1996. The two-decade-old fleet of Flyer trolleybuses were replaced with Electric Transit, Inc. (ETI) trolleybuses in the early 2000s. Likewise, the diesel bus fleet saw an infusion of 45 new NABI buses from AC Transit in 1999.

2000s
Construction on a sixth light rail line from Caltrain Depot in Mission Bay to Visitacion Valley and Bayview/Hunters Point was completed in December 2006. The new line, named the T Third Street, consisted of 19 new high-platform stations at street-level.

On October 8, 2007, SFMTA's cable car signs were awarded the AdWheel Award as the best in print promotion by the American Public Transportation Association. Nathaniel Ford, executive director of Muni, said that the "marketing group has done an outstanding job making the key boarding areas more attractive and inviting for residents and our guests."

On November 15, 2007, city officials announced that they were looking into the possibility of adding double-decker buses to the Muni fleet, which would be operating mostly on the 38 Geary and the 14 Mission routes. The test period started on December 12, 2007, and ended on January 8, 2008.

On December 1, 2007, Mayor Gavin Newsom announced that the entire city fleet, including all of Muni buses, are henceforth powered with biodiesel, a combination of 80% petroleum diesel fuel and 20% biofuel, to reduce carbon emissions. Muni's current hybrid bus fleet currently runs on biodiesel.

On July 17, 2009, a Muni LRV rear-ended another at West Portal Station. That accident injured 48 people.

On December 5, 2009, the Muni system underwent its most extensive changes in over 30 years, in an attempt by the SFMTA to reduce its budget shortfall. This involved changes to over 60% of its bus and light rail routes, including the elimination of six bus routes. Changes included reduced frequency of service, shortened or altered routes, and earlier termination of service, although a few of the busiest lines, such as the 38 Geary, saw service increases.

2010s

The 2010s started with severe cuts to Muni service. On February 26, 2010, the SFMTA board, which oversees Muni operations, voted for Muni to undergo further extensive changes in a further attempt to reduce its budget shortfall. Months after the cuts were enacted, significant portions of the service were restored through additional funding and cutting operational costs. Further improvements were made throughout the decade, amidst changes in both city and agency leadership, with the implementation of the "Muni Forward" project and all-door boarding.

In 2011, Nathaniel Ford, the head executive of the SFMTA, stepped down and Ed Reiskin took his place. After the difficult cuts in 2010, city leaders cited the "Transit Effectiveness Project", later rebranded as "Muni Forward", as a priority for improving service on Muni. In April 2015, the SFMTA launched the implementation of Muni Forward. Service changes involve renaming routes designated as "Limited" to "Rapid", a redesigned system map, and increased levels of service on the busiest bus routes. Infrastructure improvements include the addition of transit signal priority, bus bulbs, and bus-only lanes to more locations, and trackway repairs along the Muni Metro system. The 2010s also included the start of construction on bus rapid transit projects on Van Ness and Geary Streets and the initiation of planning for new subway extensions that would potentially reach the Marina District and Park Merced.

On July 1, 2012, Muni was the first transit agency in North America to implement all-door boarding throughout its system. The practice already existed in the Muni Metro as Proof-of-Payment, and was expanded to include all bus service.

With the Breda cars approaching 20 years of use, the SFMTA announced an order in 2014 for 175 new Siemens S200 cars for its Muni Metro lines. The first of the new cars was delivered in November 2017 with plans to finish the replacement of the entire fleet by 2027. This train procurement, in addition to replacing cars on existing lines, was made in order to supply the additional service required for the Central Subway and to the Mission Bay neighborhood and Chase Center. Throughout the 2010s, Muni also procured new buses and replaced over 90 percent of its diesel bus fleet and replaced all of its aging trolleybuses, improving performance for its bus fleet.

2020s
Amid the COVID-19 pandemic, ridership numbers had dropped 70–90% across the system. Muni Metro services, with an over 90% decline in riders, were replaced by bus bridges on March 30 to streamline sanitation procedures. By April 6, service had been eliminated on all but 17 of the agency's then 89 routes with San Francisco Municipal Transportation Agency Director of Transportation Jeffrey Tumlin calling it "the worst Muni service since 1906." Light rail service resumed briefly in August 2020 with significant route changes, but was discontinued and replaced by buses after just three days of operation (August 22–24) because two overhead wire splices failed in the subway portion of the line within 72 hours and an employee in the system's control center tested positive for COVID-19. The splice failures in 2020 meant that passengers could be trapped for an extended period of time in an enclosed light rail car during the pandemic. A similar splice that failed in April 2019 in the Market Street subway between Powell and Civic Center disrupted services system-wide for more than 12 hours, and led Mayor London Breed to seek a replacement for Muni head Ed Reiskin. Metallurgical analysis of the failed splices (including the failed splice from April 2019) showed the materials did not meet their specified tensile strength. Some additional bus routes have started to be restored throughout Fall 2020 and into 2021 to address overcrowding and increasing ridership including new short routes on the 1-California, 5-Fulton, and 14R Mission Rapid. On September 19, 2020, the 30-Stockton was extended to Sports Basement in The Presidio to accommodate longer, 60-foot buses along the entire route. This change resulted in many complaints from Marina District residents who complained about parking removal and low ridership along the extension. On December 19th, 2020, light rail service resumed on the J Church on a surface only route. Light rail service at the T Third Street resumed on January 23, 2021 along with the temporary resumption of the 15-Third Street on a new express route.

N Judah, K/T Ingleside/Third Street, and S Shuttle subway service resumed on May 15, 2021, as did F Market & Wharves historic streetcar service. M Ocean View rail service resumed on August 14, 2021.

Van Ness Bus Rapid Transit service began on April 1, 2022.

Muni Metro and rail service
Several proposals for Muni Metro and rail service expansion for Muni are undergoing planning and construction. In addition, several projects are underway to improve the effectiveness of existing lines, many as a part of the Muni Forward initiative. On February 19, 2016, Muni released a Draft Rail Capacity Study, which outlines proposed system improvements through the year 2050 and beyond. This three tier proposal consists of enhancements that will improve system efficiency and expand the system; estimated cost is $9–16 billion. The ConnectSF planning project, a cooperation between several city agencies including Muni, identified candidate corridors for future subway and rapid transit corridor expansion. The transit strategy report from the project concluded that two new corridors should be developed: the Geary Boulevard and 19th Avenue corridor and an extension of the Central Subway to Fisherman's Wharf.

Service improvements for the L Taraval line are under construction and projected to complete in 2024. Improvements on the J, K, and M lines have also been planned and approved, with some construction beginning in 2024. Future improvements on the N Judah line are also planned, with a long-term goal of running three-car trains on the line.

Central Subway
An underground expansion for the T line opened on November 19, 2022, after ten years of construction. Full service began on January 7, 2023. Dubbed the Central Subway, the expansion features three new underground stations at Moscone Center, Union Square, and Chinatown and one above-ground station at 4th and Brannan Streets. Construction included tunneling up to Columbus Ave and Washington Square Park but the T line stopped at Chinatown. This project cost about $1.95 billion.

Muni is also considering a future extension into North Beach and Fisherman's Wharf or to the Marina District and The Presidio which may be built in a third phase of the T Third project. Formal planning for the extension began in late 2018 with an Alternatives Study.

Buses and streetcars
The average speed of Muni vehicles has been slowly declining over the years due to increasing vehicular congestion and is now merely 8 mi per hour. In response, Muni launched plans to make its transit vehicles move faster through the city. Muni Forward (previously called the Transit Effectiveness Project) was launched in May 2006 to take a comprehensive look at the entire Muni system and to see where service can be improved or streamlined to provide faster and more reliable service. The project was launched in a context in which twenty-five years had passed since the last comprehensive review, and travel patterns had changed, traffic congestion had increased, operating costs had risen and on-time performance had dropped since then. Under the Muni Forward project, service improvements were implemented on many lines such as the 5 Fulton and 14R Mission. Further improvements on lines such as the 28 19th Avenue, 22 Fillmore, 30 Stockton, and others are planned.

For streetcar service, extending the E Embarcadero and the F Market and Wharves into Mission Bay and the Fort Mason Tunnel is possible. Existing F Market & Wharves service is planned to be improved under the Better Market Street project with a new loop at Civic Center.

Additionally, there are plans to expand trolleybus service in several parts of the city. Several extensions to existing trolleybus lines are planned, including 14-Mission service to the Daly City BART station, 6-Haight/Parnassus service to West Portal Station, 33-Ashbury/18th Street service across Potrero Hill to Third Street, 45-Union-Stockton service to the Letterman Digital Arts Center in the Presidio and 24-Divisadero service into the former Hunters Point shipyard. Other expansion plans include electrification of some diesel bus lines, with the most likely lines for conversion being the 9-San Bruno, 10-Townsend and 47-Van Ness. Electrification of the 10-Townsend line would likely be joined by an extension of the line across Potrero Hill to San Francisco General Hospital. Other lines that may be electrified are the 7-Haight-Noriega, 27-Bryant, and 43-Masonic.

title: San Francisco Municipal Railway


text:
ISO 3166-2:AE

ISO 3166-2:AE is the entry for the United Arab Emirates in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1.

Currently for the United Arab Emirates, ISO 3166-2 codes are defined for 7 emirates.

Each code consists of two parts, separated by a hyphen. The first part is AE, the ISO 3166-1 alpha-2 code of the United Arab Emirates. The second part is two letters.

Current codes
Subdivision names are listed as in the ISO 3166-2 standard published by the ISO 3166 Maintenance Agency (ISO 3166/MA).

Click on the button in the header to sort each column.

 * Notes

Changes
The following changes to the entry have been announced by the ISO 3166/MA since the first publication of ISO 3166-2 in 1998. ISO stopped issuing newsletters in 2013.

title: ISO 3166-2:AE


text:
MPEG-4 Part 3

MPEG-4 Part 3 or MPEG-4 Audio (formally ISO/IEC 14496-3) is the third part of the ISO/IEC MPEG-4 international standard developed by Moving Picture Experts Group. It specifies audio coding methods. The first version of ISO/IEC 14496-3 was published in 1999.

The MPEG-4 Part 3 consists of a variety of audio coding technologies – from lossy speech coding (HVXC, CELP), general audio coding (AAC, TwinVQ, BSAC), lossless audio compression (MPEG-4 SLS, Audio Lossless Coding, MPEG-4 DST), a Text-To-Speech Interface (TTSI), Structured Audio (using SAOL, SASL, MIDI) and many additional audio synthesis and coding techniques.

MPEG-4 Audio does not target a single application such as real-time telephony or high-quality audio compression. It applies to every application which requires the use of advanced sound compression, synthesis, manipulation, or playback. MPEG-4 Audio is a new type of audio standard that integrates numerous different types of audio coding: natural sound and synthetic sound, low bitrate delivery and high-quality delivery, speech and music, complex soundtracks and simple ones, traditional content and interactive content.

Subparts
MPEG-4 Part 3 contains following subparts:
 * Subpart 1: Main (list of Audio Object Types, Profiles, Levels, interface to ISO/IEC 14496-1, MPEG-4 Audio transport stream, etc.)
 * Subpart 2: Speech coding – HVXC (Harmonic Vector eXcitation Coding)
 * Subpart 3: Speech coding – CELP (Code Excited Linear Prediction)
 * Subpart 4: General Audio Coding (GA) (Time/Frequency Coding) – AAC, TwinVQ, BSAC
 * Subpart 5: Structured Audio (SA)
 * Subpart 6: Text to Speech Interface (TTSI)
 * Subpart 7: Parametric Audio Coding – HILN (Harmonic and Individual Line plus Noise)
 * Subpart 8: Technical description of parametric coding for high quality audio (SSC, Parametric Stereo)
 * Subpart 9: MPEG-1/MPEG-2 Audio in MPEG-4
 * Subpart 10: Technical description of lossless coding of oversampled audio (MPEG-4 DST – Direct Stream Transfer)
 * Subpart 11: Audio Lossless Coding (ALS)
 * Subpart 12: Scalable Lossless Coding (SLS)

MPEG-4 Audio Object Types
MPEG-4 Audio includes a system for handling a diverse group of audio formats in a uniform manner. Each format is assigned a unique Audio Object Type to represent it. Object Type is used to distinguish between different coding methods. It directly determines the MPEG-4 tool subset required to decode a specific object. The MPEG-4 profiles are based on the object types and each profile supports a different list of object types.

Audio Profiles
The MPEG-4 Audio standard defines several profiles. These profiles are based on the object types and each profile supports different list of object types. Each profile may also have several levels, which limit some parameters of the tools present in a profile. These parameters usually are the sampling rate and the number of audio channels decoded at the same time.

Audio storage and transport
There is no standard for transport of elementary streams over a channel, because the broad range of MPEG-4 applications have delivery requirements that are too wide to easily characterize with a single solution.

The capabilities of a transport layer and the communication between transport, multiplex, and demultiplex functions are described in the Delivery Multimedia Integration Framework (DMIF) in ISO/IEC 14496-6. A wide variety of delivery mechanisms exist below this interface, e.g., MPEG transport stream, Real-time Transport Protocol (RTP), etc.

Transport in Real-time Transport Protocol is defined in RFC 3016 (RTP Payload Format for MPEG-4 Audio/Visual Streams), RFC 3640 (RTP Payload Format for Transport of MPEG-4 Elementary Streams), RFC 4281 (The Codecs Parameter for "Bucket" Media Types) and RFC 4337 (MIME Type Registration for MPEG-4).

LATM and LOAS were defined for natural audio applications, which do not require sophisticated object-based coding or other functions provided by MPEG-4 Systems.

Bifurcation in the AAC technical standard
The Advanced Audio Coding in MPEG-4 Part 3 (MPEG-4 Audio) Subpart 4 was enhanced relative to the previous standard MPEG-2 Part 7 (Advanced Audio Coding), in order to provide better sound quality for a given encoding bitrate.

It is assumed that any Part 3 and Part 7 differences will be ironed out by the ISO standards body in the near future to avoid the possibility of future bitstream incompatibilities. At present there are no known player or codec incompatibilities due to the newness of the standard.

The MPEG-2 Part 7 standard (Advanced Audio Coding) was first published in 1997 and offers three default profiles: Low Complexity profile (LC), Main profile and Scalable Sampling Rate profile (SSR).

The MPEG-4 Part 3 Subpart 4 (General Audio Coding) combined the profiles from MPEG-2 Part 7 with Perceptual Noise Substitution (PNS) and defined them as Audio Object Types (AAC LC, AAC Main, AAC SSR).

HE-AAC
High-Efficiency Advanced Audio Coding is an extension of AAC LC using spectral band replication (SBR), and Parametric Stereo (PS). It is designed to increase coding efficiency at low bitrates by using partial parametric representation of audio.

AAC-SSR
AAC Scalable Sample Rate was introduced by Sony to the MPEG-2 Part 7 and MPEG-4 Part 3 standards. It was first published in ISO/IEC 13818-7, Part 7: Advanced Audio Coding (AAC) in 1997. The audio signal is first split into 4 bands using a 4 band polyphase quadrature filter bank. Then these 4 bands are further split using MDCTs with a size k of 32 or 256 samples. This is similar to normal AAC LC which uses MDCTs with a size k of 128 or 1024 directly on the audio signal.

The advantage of this technique is that short block switching can be done separately for every PQF band. So high frequencies can be encoded using a short block to enhance temporal resolution, low frequencies can be still encoded with high spectral resolution. However, due to aliasing between the 4 PQF bands coding efficiencies around (1,2,3) * fs/8 is worse than normal MPEG-4 AAC LC.

MPEG-4 AAC-SSR is very similar to ATRAC and ATRAC-3.

Why AAC-SSR was introduced
The idea behind AAC-SSR was not only the advantage listed above, but also the possibility of reducing the data rate by removing 1, 2 or 3 of the upper PQF bands. A very simple bitstream splitter can remove these bands and thus reduce the bitrate and sample rate.

Example:
 * 4 subbands: bitrate = 128 kbit/s, sample rate = 48 kHz, f_lowpass = 20 kHz
 * 3 subbands: bitrate ~ 120 kbit/s, sample rate = 48 kHz, f_lowpass = 18 kHz
 * 2 subbands: bitrate ~ 100 kbit/s, sample rate = 24 kHz, f_lowpass = 12 kHz
 * 1 subband: bitrate ~ 65 kbit/s, sample rate = 12 kHz, f_lowpass = 6 kHz

Note: although possible, the resulting quality is much worse than typical for this bitrate. So for normal 64 kbit/s AAC LC a bandwidth of 14–16 kHz is achieved by using intensity stereo and reduced NMRs. This degrades audible quality less than transmitting 6 kHz bandwidth with perfect quality.

BSAC
Bit Sliced Arithmetic Coding is an MPEG-4 standard (ISO/IEC 14496-3 subpart 4) for scalable audio coding. BSAC uses an alternative noiseless coding to AAC, with the rest of the processing being identical to AAC. This support for scalability allows for nearly transparent sound quality at 64 kbit/s and graceful degradation at lower bit rates. BSAC coding is best performed in the range of 40 kbit/s to 64 kbit/s, though it operates in the range of 16 kbit/s to 64 kbit/s. The AAC-BSAC codec is used in Digital Multimedia Broadcasting (DMB) applications.

Licensing
In 2002, the MPEG-4 Audio Licensing Committee selected the Via Licensing Corporation as the Licensing Administrator for the MPEG-4 Audio patent pool.

title: MPEG-4 Part 3