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Encyclopedia > Port (computing)
Ports on the Apple iBook (Early 2003)
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Ports on the Apple iBook (Early 2003)

In computing, a port (derived from seaport) is a connection through which data is sent and received. This image has been (or is hereby) released into the public domain by its creator, Hoshie. ... This image has been (or is hereby) released into the public domain by its creator, Hoshie. ... Categories: Stub | Commercial item transport and distribution | Transportation ...

Contents


Hardware port

A hardware port is an electrically wired outlet on a piece of equipment into which a plug or cable connects. These hardware ports have different physical shapes such as male, female, round, rectangular, square, oblong, etc. There is some standardization to physical properties and function. For instance, most computers have a keyboard port (currently round, or telephone type), into which the keyboard is connected. A plug is: a device which is designed to stop a fluid from flowing through a hole. ... A cable is two or more wires bound together which may be bare, covered or insulated. ... A computer keyboard is a peripheral modeled after the typewriter keyboard. ...


Hardware ports can almost always be divided into two groups:

  • Serial ports send and receive one bit at a time via a single wire pair (Ground and +/-).
  • Parallel ports send multiple bits at the same time over several sets of wires.

The system bus that holds circuit cards for a computer "Mother Board (MO)" is a form of parallel port. Note that light fiber, microwave, and other technologies (i.e. quantum) may have special cases. A male DE-9 serial port on the rear panel of a PC. In computing, a serial port is an interface on a computer system with which information is transferred in or out one bit at a time (contrast parallel port). ... In computing, a parallel port is an interface from a computer system where data are transferred in or out in parallel, that is, on more than one wire. ... Front Side Bus (FSB) is the term used to describe the CPU data bus. ...


Hardware port trunking (HPT) is a technology that allows multiple hardware ports to be aggregated into a single group, effectively creating a single connection with a higher bandwidth. This technology also provides a higher degree of fault tolerance. Compare this to Software Port Trunking (SPT) where two agents (websites, channels, etc.) are bonded into one with the same effectiveness, i.e. ISDN B1 (64K) plus B2 (64K) equals data throughput of 128K. Look up Aggregate in Wiktionary, the free dictionary The term aggregate may refer to— in communication, to collect messages from multiple sources for presentation together, as in an RSS (file format) aggregator or News aggregator. ... Bandwidth is a measure of frequency range, measured in hertz, of a function of a frequency variable. ... Fault-tolerance or graceful degradation is the property of a system that continues operating properly in the event of failure of some of its parts. ...


Network port

Please improve this section according to the posted request for expansion.

One can imagine computers having thousands of numbered hardware ports, each with wires sticking out of them. In this imagined scenario, applications could communicate as follows: Application A listens for network traffic arriving on, say, port 90. Application B knows that Application A is always listening on port 90, so it sends some data down the corresponding wire. The number of concurrent listening applications is limited by the number of wires there are sticking out of the computer. This is the illusion created by network ports. Of course, in reality, there is (usually) only one hardware port (the network socket). The illusion is created by sending data to this single hardware port, but including in the transmission the number of the network port. Thus, an application can choose to see only traffic sent to its port.


Whether or not network ports are used depends on the transport layer. Both UDP and TCP use ports. In computing and telecommunications, the transport layer is layer four of the seven layer OSI model. ... The User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ...


A port may send/receive data one direction at a time (simplex) or simultaneously in both directions (duplex). Software network ports may also connect internal programs on a single computer system.


In TCP and UDP the combination of a port and a network address (IP-number) is called a socket: e.g. the TCP and UDP port numbers. The Internet Protocol (IP) is a data-oriented protocol used by source and destination hosts for communicating data across a packet-switched internetwork. ... A socket generally designates a cavity or region used for fitting and connecting some specific device. ... IANA is responsible for assigning TCP and UDP port numbers to specific uses. ...


I/O or machine port mechanism - port-mapped I/O

For Input or Output (I/O) operations nearly all processor families use similar assembly instructions for both memory access and hardware I/O (see memory-mapped I/O for details). However, Intel microprocessors have assembly instructions (IN and OUT) that are used specifically for hardware I/O. These instructions figure out which hardware device to communicate with using the concept of an I/O port or machine port. These ports are numbered based on which hardware device they refer to. In computing, a hardware register is a storage area for hardware I/O (input/output) of different kinds. ... For more generic meanings of input/output port, see port (computing). ... This generational and chronological list of Intel microprocessors attempts to present all of Intels processors (µPs) from the pioneering 4-bit 4004 (1971) to the present high-end offerings, the 64-bit Itanium 2 (2002) and Pentium 4F with EM64T (2004). ...


Intel microprocessors generally allow one octet (8-bit byte or word) to be sent or received during each instruction. The hardware device decides how to interpret data sent to it and what data to send to the processor. For example, a common use is to ask a hardware device which byte (in a data transfer) it will be sending next. An octet is a group consisting of eight (8) elements, but it has several more specific meanings (usually given by a specific field or application): Music In music, an octet is a musical ensemble consisting of eight instruments or a musical composition written for it. ...


See also


  Results from FactBites:
 
port (computing) (255 words)
In computing, a socket that enables a computer processor to communicate with an external device.
It may be an input port (such as a joystick port), or an output port (such as a printer port), or both (an i/o port).
Microcomputers may provide ports for cartridges, televisions and/or monitors, printers, and modems, and sometimes for hard disks and musical instruments (MIDI, the musical-instrument digital interface).
ThinkGeek :: Computing (351 words)
Turn 1 USB port into 4 with this clever little USB hub.
Your very own TARDIS controls 4 USB Ports!
Professional quality turntable connects to your PC with USB and allows you to rip your old vinyl to MP3.
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