Misplaced Pages

#365634

64-405: ITS, and the software developed on it, were technically and culturally influential far beyond their core user community. Remote "guest" or "tourist" access was easily available via the early ARPANET , allowing many interested parties to informally try out features of the operating system and application programs. The wide-open ITS philosophy and collaborative online community were a major influence on

128-534: 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

192-616: A combined effort between people on the ITS machines at MIT and at Stanford University SAIL . The document described much of the terminology, puns, and culture of the two AI Labs and related research groups, and is the direct predecessor of the Hacker's Dictionary (1983), the first compendium of hacker jargon to be issued by a major publisher ( MIT Press ). Different implementations of ITS supported an odd array of peripherals, including an automatic wire stripper devised by hacker Richard Greenblatt, who needed

256-597: 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

320-428: A restricted subset of DDT's functionality—is run first and is overlaid with DDT as soon as the user logs in. DDT could run and debug up to eight processes (called "jobs" on ITS) at a time, such as several sessions of TECO , and DDT could be run recursively - that is, some or all of those jobs could themselves be DDTs (which could then run another eight jobs, and so on). These eight jobs were all given unique names, and

384-424: A supply of pre-stripped jumper wires of various lengths for wire-wrapping computer hardware he and others were prototyping. The device used a stepper motor and a formerly hand-held wire stripper tool and cutter, operated by solenoid , all under computer control from ITS software. The device was accessible by any ITS user, but was disappointingly unreliable in actual use. The Xerox Graphics Printer (XGP), one of

448-475: 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

512-599: 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

576-583: 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

640-535: 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. Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). The transatlantic connectivity with NORSAR and UCL later evolved into

704-645: The Defense Communications Agency in 1975. Bob Kahn moved to DARPA and, together with Vint Cerf at Stanford University , formulated the Transmission Control Program for internetworking . As this work progressed, a protocol was developed by which multiple separate networks could be joined into a network of networks; this incorporated concepts pioneered in the French CYCLADES project directed by Louis Pouzin . Version 4 of TCP/IP

SECTION 10

#1732844316366

768-649: The Digital Equipment Corporation PDP-6 computer, but the majority of ITS development and use was on the later, largely compatible, PDP-10 . Although not used as intensively after about 1986, ITS continued to operate on original hardware at MIT until 1990, and then until 1995 at Stacken Computer Club in Sweden. Today, some ITS implementations continue to be remotely accessible, via emulation of PDP-10 hardware running on modern, low-cost computers supported by interested hackers. ITS introduced many then-new features: The environment seen by ITS users

832-902: 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,

896-537: 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. Historically, voice and data communications were based on methods of circuit switching , as exemplified in the traditional telephone network, wherein each telephone call

960-502: 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. In September 1984 work

1024-536: 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

1088-539: The hacker culture , as described in Steven Levy's book Hackers , and were the direct forerunners of the free and open-source software , open-design , and Wiki movements. ITS development was initiated in the late 1960s by those (the majority of the MIT AI Lab staff at that time) who disagreed with the direction taken by Project MAC's Multics project (which had started in the mid-1960s), particularly such decisions as

1152-572: 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

1216-451: 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. The first four nodes were designated as

1280-430: 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

1344-586: 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

SECTION 20

#1732844316366

1408-535: 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

1472-690: The DEC name DDT (and DDT-86 and DDT-68K) for their debugger, however, now meaning Dynamic Debugging Tool . The CP/M DDT was later superseded by the Symbolic Instruction Debugger (SID, ZSID, SID86 , and GEMSID ) in DR ;DOS and GEM . In addition to its normal function as a debugger, DDT was also used as a top-level command shell for the Massachusetts Institute of Technology (MIT) Incompatible Timesharing System (ITS) operating system ; on some more recent ITS systems, "PWORD"—which implements

1536-526: The Department of Defense allowed the universities to join the network for sharing hardware and software resources. 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,

1600-549: 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 50 kbit /s . The host computers were connected to

1664-399: 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. As with the NPL network, the first-generation IMPs were built by BBN using a rugged computer version of

1728-578: 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. Dynamic debugging technique Dynamic Debugging Technique ( DDT ) is a series of debugger programs originally developed for Digital Equipment Corporation (DEC) hardware, initially known as DEC Debugging Tape because it

1792-542: The MIT lab, to control usage of printer supplies which had to be specially ordered. CTSS and ITS file systems have a number of design elements in common. Both have an M.F.D. (master file directory) and one or more U.F.D. (user file directories). Neither of them have nested directories (sub-directories) Both have file names consisting of two names which are a maximum of six-characters long. Both support linked files. ARPANET Early research and development: Merging

1856-462: 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,

1920-459: The basis of Infocom 's programming environment), and Scheme . Among other significant and influential software subsystems developed on ITS, the Macsyma symbolic algebra system, started in 1968, was the first widely-known mathematical computing environment. It was a forerunner of Maxima , MATLAB , Wolfram Mathematica , and many other computer algebra systems . Terry Winograd 's SHRDLU program

1984-463: 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. 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

Incompatible Timesharing System - Misplaced Pages Continue

2048-691: 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

2112-470: The first laser printers in the world, was supported by ITS by 1974. The MIT AI Lab had one of these prototype continuous roll-fed printers for experimentation and use by its staff. By 1982, the XGP was supplemented by a Xerox Dover printer, an early sheet-fed laser printer. Although any ITS user could access the laser printers, physical access to pick up printouts was limited to staff and others who obtained access to

2176-491: The inclusion of powerful system security . The name was chosen by Tom Knight as a joke on the name of the earliest MIT time-sharing operating system, the Compatible Time-Sharing System , which dated from the early 1960s. By simplifying their system compared to Multics, ITS's authors were able to quickly produce a functional operating system for their lab. ITS was written in assembly language , originally for

2240-542: 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. 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

2304-569: 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

2368-524: The networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: 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

2432-452: 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

2496-494: 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 others. 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

2560-597: The performance of packet-switched networks, which underpinned the development of the ARPANET as it expanded rapidly in the early 1970s. 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

2624-518: 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

Incompatible Timesharing System - Misplaced Pages Continue

2688-442: 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

2752-543: 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

2816-610: 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

2880-461: 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,

2944-573: 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. In February 1966, Bob Taylor successfully lobbied ARPA's Director Charles M. Herzfeld to fund

3008-652: 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

3072-459: The usual name for the original and top-most DDT was "HACTRN" ("hack-tran"). Guy L. Steele wrote a filk poem parody of Edgar Allan Poe 's " The Raven ," entitled The HACTRN . DDT (Dynamic Debugging Technique), as implemented on the DECsystem-10 & DECSYSTEM-20 allowed references to symbols within the programming being debugged. This feature loaded symbols from the .EXE executable file;

3136-446: 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,

3200-495: Was called PEEK. The local spelling "TURIST" is an artifact of six-character filename (and other identifier) limitations, which is traceable to six SIXBIT encoded characters fitting into a single 36-bit PDP-10 word. "TURIST" may also have been a pun on Alan Turing , a pioneer of theoretical computer science . The less-complimentary term " LUSER " was also applied to guest users, especially those who repeatedly engaged in clueless or vandalous behavior. The Jargon File started as

3264-464: 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

SECTION 50

#1732844316366

3328-591: 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. ARPA

3392-545: 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

3456-606: Was declared operational in 1971. Network traffic began to grow once email was established at the majority of sites by around 1973. 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: The first successful host-to-host connection on

3520-658: Was developed in ITS. The computer game Zork was also originally written on ITS. Richard Greenblatt 's Mac Hack VI was the top-rated chess program for years and was the first to display a graphical board representation. The default ITS top-level command interpreter was the PDP-10 machine language debugger ( DDT ). The usual text editor on ITS was TECO and later Emacs , which was written in TECO. Both DDT and TECO were implemented through simple dispatch tables on single-letter commands, and thus had no true syntax . The ITS task manager

3584-463: Was distributed on paper tape . The name is a pun on the insecticide DDT . The first version of DDT was developed at MIT for the PDP-1 computer in 1961, but newer versions on newer platforms continued to use the same name. After being ported to other vendor's platforms and changing media, the name was changed to the less DEC-centric version. Early versions of Digital Research 's CP/M and CP/M-86 kept

3648-464: 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

3712-502: 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

3776-423: 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

3840-448: Was philosophically significantly different from that provided by most operating systems at the time. The wide-open ITS philosophy and collaborative community were the direct forerunner of the free and open-source software , open-design , and Wiki movements. The EMACS ("Editor MACroS") editor was originally written on ITS. In its ITS instantiation it was a collection of TECO programs (called "macros"). On later operating systems, it

3904-434: 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

SECTION 60

#1732844316366

3968-461: Was that all mainframe computers would connect to one another directly. The other investigators were reluctant to dedicate these computing resources to network administration. After the design session, 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

4032-480: 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,

4096-597: Was written in the common language of those systems – for example, the C language under Unix, and Zetalisp under the Lisp Machine system. GNU ‘s info help system was originally an EMACS subsystem, and then was later written as a complete standalone system for Unix-like machines. Several important programming languages and systems were developed on ITS, including MacLisp (the precursor of Zetalisp and Common Lisp ), Microplanner (implemented in MacLisp), MDL (which became

#365634