Plan 55-A was one in a series of store and forward message switching systems developed by Western Union and used from 1948 to 1976 for processing telegrams. It is an automated successor to Plan 51, which commenced service in 1951 in a nationwide network of the U. S. Air required semi-automatic operation. Based on the technology of punched paper tape storage, the systems of the design were called reperforators. A reperforator performed functions similar to an email message transfer agent, used much in the Internet, but it used electro-mechanical technology, which preceded the use of semiconductor circuitry and computers. A reperforator switching center received messages via serial communication lines from teleprinters, such as the Teletype Model 28 ASR, or from other switching centers on receiving consoles, each consisting of a paper tape punch feeding tape into a paper tape reader via a storage bin; the reader decoded the message header, sent the header characters to the director. The director, much like a telephone switch, connected the receiving console to a sending console in the same switching center by a cross-office connection.
The message was transmitted from the receiving console to the sending console, character by character, punching a second paper tape at the sending console. Cross-office connections, their readers and punches, were faster than external connections, to limit congestion to the edges of the network; each sending console consisted of a paper tape punch and reader. Output from each sending console was transmitted via outgoing lines to other switching centers or to destination teleprinters; each message contained one telegram. Each received message had up to nine routing destinations. For two or three destinations, the messages were sent on three cross-office connections to outgoing sending consoles. Additional destinations resulted in a copy of the message being sent to the multiple call spillover unit, which removed the routing indicators for destinations handled and sent the message through the system again. Nationwide, Western Union's switching centers were arranged in a hub and spokes architecture involving fifteen locations.
The U. S. Air Force used the Plan 55-A system worldwide with ten centers. An analysis of the queueing delays in Plan 55-A by Leonard Kleinrock formed part of the theoretical basis for the development of the ARPAnet. Teleprinter Western Union Telegraph Company. "Telegram for America". A non-technical industrial film showing telegram handling in the 1950s. Plan 55-A switching centers are shown in some detail
A teleprinter is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. They were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering; the machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could be used to create punched tape for data storage and to read back such tape for local printing or transmission. Teleprinters could use a variety of different communication media; these included a simple pair of wires. A teleprinter attached to a modem could communicate through standard switched public telephone lines; this latter configuration was used to connect teleprinters to remote computers in time-sharing environments. Teleprinters have been replaced by electronic computer terminals which have a computer monitor instead of a printer.
Teleprinters are still used in the aviation industry, variations called Telecommunications Devices for the Deaf are used by the hearing impaired for typed communications over ordinary telephone lines. The teleprinter evolved through a series of inventions by a number of engineers, including Samuel Morse, Alexander Bain, Royal Earl House, David Edward Hughes, Emile Baudot, Donald Murray, Charles L. Krum, Edward Kleinschmidt and Frederick G. Creed. Teleprinters were invented in order to send and receive messages without the need for operators trained in the use of Morse code. A system of two teleprinters, with one operator trained to use a keyboard, replaced two trained Morse code operators; the teleprinter system improved message speed and delivery time, making it possible for messages to be flashed across a country with little manual intervention. There were a number of parallel developments on both sides of the Atlantic Ocean. In 1835 Samuel Morse devised a recording telegraph, Morse code was born.
Morse's instrument used a current to displace an electromagnet, which moved a marker, therefore recording the breaks in the current. Cooke & Wheatstone received a British patent covering telegraphy in 1837 and a second one in 1840 which described a type-printing telegraph with steel type fixed at the tips of petals of a rotating brass daisy-wheel, struck by an “electric hammer” to print Roman letters through carbon paper onto a moving paper tape. In 1841 Alexander Bain devised an electromagnetic printing telegraph machine, it used pulses of electricity created by rotating a dial over contact points to release and stop a type-wheel turned by weight-driven clockwork. The critical issue was to have the sending and receiving elements working synchronously. Bain attempted to achieve this using centrifugal governors to regulate the speed of the clockwork, it was patented, along with other devices, on April 21, 1841. By 1846, the Morse telegraph service was operational between Washington, D. C. and New York.
Royal Earl House patented his printing telegraph that same year. He linked two 28-key piano-style keyboards by wire; each piano key represented a letter of the alphabet and when pressed caused the corresponding letter to print at the receiving end. A "shift" key gave each main key two optional values. A 56-character typewheel at the sending end was synchronised to coincide with a similar wheel at the receiving end. If the key corresponding to a particular character was pressed at the home station, it actuated the typewheel at the distant station just as the same character moved into the printing position, in a way similar to the daisy wheel printer, it was thus an example of a synchronous data transmission system. House's equipment could transmit around 40 readable words per minute, but was difficult to manufacture in bulk; the printer could print out up to 2,000 words per hour. This invention was first put in operation and exhibited at the Mechanics Institute in New York in 1844. Landline teleprinter operations began in 1849, when a circuit was put in service between Philadelphia and New York City.
In 1855, David Edward Hughes introduced an improved machine built on the work of Royal Earl House. In less than two years, a number of small telegraph companies, including Western Union in early stages of development, united to form one large corporation – Western Union Telegraph Co. – to carry on the business of telegraphy on the Hughes system. In France, Émile Baudot designed in 1874 a system using a five-unit code, which began to be used extensively in that country from 1877; the British Post Office adopted the Baudot system for use on a simplex circuit between London and Paris in 1897, subsequently made considerable use of duplex Baudot systems on their Inland Telegraph Services. During 1901, Baudot's code was modified by Donald Murray, prompted by his development of a typewriter-like keyboard; the Murray system employed an intermediate step, a keyboard perforator, which allowed an operator to punch a paper tape, a tape transmitter for sending the message from the punched tape. At the receiving end of the line, a printing mechanism would
A communication channel or channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used to convey an information signal, for example a digital bit stream, from one or several senders to one or several receivers. A channel has a certain capacity for transmitting information measured by its bandwidth in Hz or its data rate in bits per second. Communicating data from one location to another requires some form of medium; these pathways, called communication channels, use two types of media: broadcast. Cable or wire line media use physical wires of cables to transmit data and information. Twisted-pair wire and coaxial cables are made of copper, fiber-optic cable is made of glass. In information theory, a channel refers to a theoretical channel model with certain error characteristics. In this more general view, a storage device is a kind of channel, which can be sent to and received from.
Examples of communications channels include: A connection between initiating and terminating nodes of a circuit. A single path provided by a transmission medium via either physical separation, such as by multipair cable or electrical separation, such as by frequency-division or time-division multiplexing. A path for conveying electrical or electromagnetic signals distinguished from other parallel paths. A storage which can communicate a message over time as well as space The portion of a storage medium, such as a track or band, accessible to a given reading or writing station or head. A buffer from which messages can be'put' and'got'. See Actor model and process calculi for discussion on the use of channels. In a communications system, the physical or logical link that connects a data source to a data sink. A specific radio frequency, pair or band of frequencies named with a letter, number, or codeword, allocated by international agreement. Examples: Marine VHF radio uses some 88 channels in the VHF band for two-way FM voice communication.
Channel 16, for example, is 156.800 MHz. In the US, seven additional channels, WX1 - WX7, are allocated for weather broadcasts. Television channels such as North American TV Channel 2 = 55.25 MHz, Channel 13 = 211.25 MHz. Each channel is 6 MHz wide; this was based on the bandwidth required by older analog television signals. Since 2006 television broadcasting has switched to digital modulation which uses image compression to transmit a television signal in a much smaller bandwidth, so each of these "physical channels" has been divided into multiple "virtual channels" each carrying a DTV channel. Wi-Fi uses 13 channels from 2412 MHz to 2484 MHz in 5 MHz steps, in the ISM bands; the radio channel between an amateur radio repeater and a ham uses two frequencies 600 kHz apart. For example, a repeater that transmits on 146.94 MHz listens for a ham transmitting on 146.34 MHz. All of these communications channels share the property; the information is carried through the channel by a signal. A channel can be modelled physically by trying to calculate the physical processes which modify the transmitted signal.
For example, in wireless communications the channel can be modelled by calculating the reflection off every object in the environment. A sequence of random numbers might be added in to simulate external interference and/or electronic noise in the receiver. Statistically a communication channel is modelled as a triple consisting of an input alphabet, an output alphabet, for each pair of input and output elements a transition probability p. Semantically, the transition probability is the probability that the symbol o is received given that i was transmitted over the channel. Statistical and physical modelling can be combined. For example, in wireless communications the channel is modelled by a random attenuation of the transmitted signal, followed by additive noise; the attenuation term is a simplification of the underlying physical processes and captures the change in signal power over the course of the transmission. The noise in the model electronic noise in the receiver. If the attenuation term is complex it describes the relative time a signal takes to get through the channel.
The statistics of the random attenuation are decided by previous measurements or physical simulations. Channel models may be continuous channel models in that there is no limit to how their values may be defined. Communication channels are studied in a discrete-alphabet setting; this corresponds to abstracting a real world communication system in which the analog → digital and digital → analog blocks are out of the control of the designer. The mathematical model consists of a transition probability that specifies an output distribution for each possible sequence of channel inputs. In information theory, it is common to start with memoryless channels in which the output probability distribution only depends on the current channel input. A channel model may either be analog. In a digital channel model, the transmitted message is modelled as a digital signal at a certain protocol layer. Underlying protocol layers, such as the physical layer transmission technique, is replaced by a simplified model.
The model may reflect channel performance measures such as bit rate, bit errors, latency/delay, delay jitter, etc. Examples of digital channel models are: Binary symmetric channel, a discrete memoryless channel with a
Bulletin board system
A bulletin board system or BBS is a computer server running software that allows users to connect to the system using a terminal program. Once logged in, the user can perform functions such as uploading and downloading software and data, reading news and bulletins, exchanging messages with other users through public message boards and sometimes via direct chatting. In the middle to late 1980s, message aggregators and bulk store-and-forward'ers sprung up to provide services such as FidoNet, similar to email. Many BBSes offer online games in which users can compete with each other. BBSes with multiple phone lines provide chat rooms, allowing users to interact with each other. Bulletin board systems were in many ways a precursor to the modern form of the World Wide Web, social networks, other aspects of the Internet. Low-cost, high-performance modems drove the use of online services and BBSes through the early 1990s. Infoworld estimated that there were 60,000 BBSes serving 17 million users in the United States alone in 1994, a collective market much larger than major online services such as CompuServe.
The introduction of inexpensive dial-up internet service and the Mosaic web browser offered ease of use and global access that BBS and online systems did not provide, led to a rapid crash in the market starting in 1994. Over the next year, many of the leading BBS software providers went bankrupt and tens of thousands of BBSes disappeared. Today, BBSing survives as a nostalgic hobby in most parts of the world, but it is still an popular form of communication for Taiwanese youth. Most surviving BBSes are accessible over Telnet and offer free email accounts, FTP services, IRC and all the protocols used on the Internet; some offer access through packet switched networks or packet radio connections. A precursor to the public bulletin board system was Community Memory, started in August 1973 in Berkeley, California. Useful microcomputers did not exist at that time, modems were both expensive and slow. Community Memory therefore ran on a mainframe computer and was accessed through terminals located in several San Francisco Bay Area neighborhoods.
The poor quality of the original modem connecting the terminals to the mainframe prompted a user to invent the Pennywhistle modem, whose design was influential in the mid-1970s. Community Memory allowed the user to type messages into a computer terminal after inserting a coin, offered a "pure" bulletin board experience with public messages only, it did offer the ability to tag messages with keywords. The system acted in the form of a buy and sell system with the tags taking the place of the more traditional classifications, but users found ways to express themselves outside these bounds, the system spontaneously created stories and other forms of communications. The system was expensive to operate, when their host machine became unavailable and a new one could not be found, the system closed in January 1975. Similar functionality was available to most mainframe users, which might be considered a sort of ultra-local BBS when used in this fashion. Commercial systems, expressly intended to offer these features to the public, became available in the late 1970s and formed the online service market that lasted into the 1990s.
One influential example was PLATO, which had thousands of users by the late 1970s, many of whom used the messaging and chat room features of the system in the same way that would become common on BBSes. Early modems were very simple devices using acoustic couplers to handle telephone operation; the user would first pick up the phone, dial a number press the handset into rubber cups on the top of the modem. Disconnecting at the end of a call required the user to pick up the handset and return it to the phone. Examples of direct-connecting modems did exist, these allowed the host computer to send it commands to answer or hang up calls, but these were expensive devices used by large banks and similar companies. With the introduction of microcomputers with expansion slots, like the S-100 bus machines and Apple II, it became possible for the modem to communicate instructions and data on separate lines. A number of modems of this sort were available by the late 1970s; this made the BBS possible for the first time, as it allowed software on the computer to pick up an incoming call, communicate with the user, hang up the call when the user logged off.
The first public dial-up BBS was developed by Randy Suess. According to an early interview, when Chicago was snowed under during the Great Blizzard of 1978, the two began preliminary work on the Computerized Bulletin Board System, or CBBS; the system came into existence through a fortuitous combination of Christensen having a spare S-100 bus computer and an early Hayes internal modem, Suess's insistence that the machine be placed at his house in Chicago where it would be a local phone call to millions of users. Christensen patterned the system after the cork board his local computer club used to post information like "need a ride". CBBS went online on 16 February 1978. CBBS, which kept a count of callers connected 253,301 callers before it was retired. A key innovation required for the popularization of the BBS was the Smartmodem manufactured by Hayes Microcomputer Products. Internal modems like the ones used by CBBS and similar early systems were usable, but expensive due to the manufacturer having to make a different modem for every computer platform they wanted to target.
They were limited to those
Packet radio is a form of packet switching technology used to transmit digital data via wireless communications. Packet radio uses the same concepts of data transmission using datagrams that are fundamental to communications on the Internet, as opposed to older techniques used by dedicated or switched circuits. Packet radio can be used over long distances without the need for a physical connection between stations. Packet radio can be used for mobile communications. Packet radio is a digital radio communications mode. Earlier digital modes were telegraphy and facsimile; the most common use of packet radio is in amateur radio. Packet radio uses the AX.25 data link layer protocol, derived from the X.25 protocol suite and adapted for amateur radio use. AX.25 was developed in the 1970s. Every AX.25 packet contains the sender's and recipient's amateur radio callsign, thus providing station identification with every transmission. AX.25 includes a digipeater field to allow other stations to automatically repeat packets to extend the range of transmissions.
It is possible for any packet station to act as a digipeater, linking distant stations with each other through ad hoc networks. This makes packet radio useful for emergency communications. Mobile packet radio stations can automatically transmit their location, check in periodically with the network to show that they are still operating. Since radio circuits inherently possess a broadcast network topology, one of the first technical challenges faced in the implementation of packet radio networks was a means to control access to a shared communication channel. Professor Norman Abramson of the University of Hawaii led development a packet radio network known as ALOHAnet and performed a number of experiments beginning in the 1970s to develop methods to arbitrate access to a shared radio channel by network nodes; this system operated on UHF frequencies at 9,600 baud. From this work the Aloha multiple access protocol was derived. Subsequent enhancements in channel access techniques made by Leonard Kleinrock et al. in 1975 would lead Robert Metcalfe to use carrier sense multiple access protocols in the design of the now commonplace Ethernet local area network technology.
Over 1973–76, DARPA created a packet radio network called PRNET in the San Francisco Bay area and conducted a series of experiments with SRI to verify the use of ARPANET communications protocols over packet radio links between mobile and fixed network nodes. This system was quite advanced, as it made use of direct sequence spread spectrum modulation and forward error correction techniques to provide 100 kbit/s and 400 kbit/s data channels; these experiments were considered to be successful, marked the first demonstration of Internetworking, as in these experiments data was routed between the ARPANET, PRNET, SATNET networks. Throughout the 1970s and 1980s, DARPA operated a number of terrestrial and satellite packet radio networks connected to the ARPANET at various military and government installations. Amateur radio operators began experimenting with packet radio in 1978, when—after obtaining authorization from the Canadian government—Robert Rouleau, VE2PY. In 1980, Doug Lockhart VE7APU, the Vancouver Area Digital Communications Group in Vancouver, British Columbia began producing standardized equipment in quantity for use in amateur packet radio networks.
In 2003, Rouleau was inducted into CQ Amateur Radio magazine's hall of fame for his work on the Montreal Protocol in 1978. Not long after this activity began in Canada, amateurs in the US became interested in packet radio. In 1980, the United States Federal Communications Commission granted authorization for United States amateurs to transmit ASCII codes via amateur radio. Repeaters may be designed for amateur packet radio, these are dubbed "digipeaters"; the first known amateur packet radio activity in the US occurred in San Francisco during December 1980, when a packet repeater was put into operation on 2 meters by Hank Magnuski KA6M, the Pacific Packet Radio Society. In keeping with the dominance of DARPA and ARPANET at the time, the nascent amateur packet radio network was dubbed the AMPRNet in DARPA style. Magnuski obtained IP address allocations in the 18.104.22.168 network for amateur radio use worldwide. Many groups of amateur radio operators interested in packet radio soon formed throughout the country including the Pacific Packet Radio Society in California, the Tucson Amateur Packet Radio Corporation in Arizona and the Amateur Radio Research and Development Corporation in Washington, D.
C. By 1983, TAPR was offering the first TNC available in kit form. Packet radio started becoming more and more popular across North America and by 1984 the first packet-based bulletin board systems began to appear. Packet radio proved its value for emergency operations following the crash of an Aeromexico airliner in a neighborhood in Cerritos, California Labor Day weekend, 1986. Volunteers linked several key sites to pass text traffic via packet radio which kept voice frequencies clear. For an objective description of early developments in amateur packet radio, refer to the article "Packet Radio in the Amateur Service"; the most common use of packet radio today is in amateur radio, to construct wireles
Electronic mail is a method of exchanging messages between people using electronic devices. Invented by Ray Tomlinson, email first entered limited use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, which today is the Internet; some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward and store messages. Neither the users nor their computers are required to be online simultaneously. An ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, has been standardized, but as of 2017 it has not been adopted; the history of modern Internet email services reaches back to the early ARPANET, with standards for encoding email messages published as early as 1973.
An email message sent in the early 1970s looks similar to a basic email sent today. Email had an important role in creating the Internet, the conversion from ARPANET to the Internet in the early 1980s produced the core of the current services; the term electronic mail was used generically for any electronic document transmission. For example, several writers in the early 1970s used the term to describe fax document transmission; as a result, it is difficult to find the first citation for the use of the term with the more specific meaning it has today. Electronic mail has been most called email or e-mail since around 1993, but variations of the spelling have been used: email is the most common form used online, is required by IETF Requests for Comments and working groups and by style guides; this spelling appears in most dictionaries. E-mail is the format that sometimes appears in edited, published American English and British English writing as reflected in the Corpus of Contemporary American English data, but is falling out of favor in some style guides.
Mail was the form used in the original protocol standard, RFC 524. The service is referred to as mail, a single piece of electronic mail is called a message. EMail is a traditional form, used in RFCs for the "Author's Address" and is expressly required "for historical reasons". E-mail is sometimes used, capitalizing the initial E as in similar abbreviations like E-piano, E-guitar, A-bomb, H-bomb. An Internet e-mail consists of an content. Computer-based mail and messaging became possible with the advent of time-sharing computers in the early 1960s, informal methods of using shared files to pass messages were soon expanded into the first mail systems. Most developers of early mainframes and minicomputers developed similar, but incompatible, mail applications. Over time, a complex web of gateways and routing systems linked many of them. Many US universities were part of the ARPANET, which aimed at software portability between its systems; that portability helped make the Simple Mail Transfer Protocol influential.
For a time in the late 1980s and early 1990s, it seemed that either a proprietary commercial system or the X.400 email system, part of the Government Open Systems Interconnection Profile, would predominate. However, once the final restrictions on carrying commercial traffic over the Internet ended in 1995, a combination of factors made the current Internet suite of SMTP, POP3 and IMAP email protocols the standard; the diagram to the right shows a typical sequence of events that takes place when sender Alice transmits a message using a mail user agent addressed to the email address of the recipient. The MUA formats the message in email format and uses the submission protocol, a profile of the Simple Mail Transfer Protocol, to send the message content to the local mail submission agent, in this case smtp.a.org. The MSA determines the destination address provided in the SMTP protocol, in this case firstname.lastname@example.org, a qualified domain address. The part before the @ sign is the local part of the address the username of the recipient, the part after the @ sign is a domain name.
The MSA resolves a domain name to determine the qualified domain name of the mail server in the Domain Name System. The DNS server for the domain b.org responds with any MX records listing the mail exchange servers for that domain, in this case mx.b.org, a message transfer agent server run by the recipient's ISP. smtp.a.org sends the message to mx.b.org using SMTP. This server may need to forward the message to other MTAs before the message reaches the final message delivery agent; the MDA delivers it to the mailbox of user bob. Bob's MUA picks up the message using either the Post Office Protocol or the Internet Message Access Protocol. In addition to this example and complications exist in the email system: Alice or Bob may use a client connected to a corporate email system, such as IBM Lotus Notes or Microsoft Exchange; these systems have their own internal email format and their clients communicate with the email server using a vendor-specific, proprietary protocol. The server sends or receives email via the Internet through the product's Internet mail gateway which does any necessary reformatt
An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages. They differ from chat rooms in that messages are longer than one line of text, are at least temporarily archived. Depending on the access level of a user or the forum set-up, a posted message might need to be approved by a moderator before it becomes publicly visible. Forums have a specific set of jargon associated with them. A discussion forum is hierarchical or tree-like in structure: a forum can contain a number of subforums, each of which may have several topics. Within a forum's topic, each new discussion started is called a thread and can be replied to by as many people as so wish. Depending on the forum's settings, users can be anonymous or have to register with the forum and subsequently log in to post messages. On most forums, users do not have to log in to read existing messages; the modern forum originated from bulletin boards, so-called computer conferencing systems, are a technological evolution of the dialup bulletin board system.
From a technological standpoint, forums or boards are web applications managing user-generated content. Early Internet forums could be described as a web version of an electronic mailing list or newsgroup. Developments emulated the different newsgroups or individual lists, providing more than one forum, dedicated to a particular topic. Internet forums are prevalent in several developed countries. Japan posts the most with over two million per day on 2channel. China has many millions of posts on forums such as Tianya Club; some of the first forum systems were the Planet-Forum system, developed at the beginning of the 1970-s, the EIES system, first operational in 1976, the KOM system, first operational in 1977. One of the first forum sites is Delphi Forums, once called Delphi; the service, with four million members, dates to 1983. Forums perform a function similar to that of dial-up bulletin board systems and Usenet networks that were first created starting in the late 1970s. Early web-based forums date back as far as 1994, with the WIT project from W3 Consortium and starting from this time, many alternatives were created.
A sense of virtual community develops around forums that have regular users. Technology, video games, music, fashion and politics are popular areas for forum themes, but there are forums for a huge number of topics. Internet slang and image macros popular across the Internet are abundant and used in Internet forums. Forum software packages are available on the Internet and are written in a variety of programming languages, such as PHP, Java and ASP; the configuration and records of posts can be stored in a database. Each package offers different features, from the most basic, providing text-only postings, to more advanced packages, offering multimedia support and formatting code. Many packages can be integrated into an existing website to allow visitors to post comments on articles. Several other web applications, such as blog software incorporate forum features. WordPress comments at the bottom of a blog post allow for a single-threaded discussion of any given blog post. Slashcode, on the other hand, is far more complicated, allowing threaded discussions and incorporating a robust moderation and meta-moderation system as well as many of the profile features available to forum users.
Some stand alone threads on forums have reached fame and notability such as the "I am lonely will anyone speak to me" thread on MovieCodec.com's forums, described as the "web's top hangout for lonely folk" by Wired Magazine. A forum consists of a tree-like directory structure; the top end is "Categories". A forum can be divided into categories for the relevant discussions. Under the categories are sub-forums and these sub-forums can further have more sub-forums; the topics come under the lowest level of sub-forums and these are the places under which members can start their discussions or posts. Logically forums are organized into a finite set of generic topics driven and updated by a group known as members, governed by a group known as moderators, it can have a graph structure. All message boards will use one of three possible display formats; each of the three basic message board display formats: Non-Threaded/Semi-Threaded/Fully Threaded, has its own advantages and disadvantages. If messages are not related to one another at all, a Non-Threaded format is best.
If a user has a message topic and multiple replies to that message topic, a semi-threaded format is best. If a user has a message topic and replies to that message topic and responds to replies a threaded format is best. Internally, Western-style forums logged in members into user groups. Privileges and rights are given based on these groups. A user of the forum can automatically be promoted to a more privileged user group based on criteria set by the administrator. A person viewing a closed thread as a member will see a box saying he does not have the right to submit messages there, but a moderator will see the same box granting him access to more than just posting messages. An unregistered user of the site is known as a guest or visitor. Guests are granted access to all functions that do not require database alterations or breach privacy. A guest can view the contents of the forum or use such features as read marking, but an administrator will disallow visi