Computer Term Glossary

Originally created ~1998
First posted Feb 10, 2007
Last update Mar 25, 2015
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All content, except as otherwise noted, is © Frank Harrell. Text may be reposted only if credit is given and a link is provided to CowboyFrank.net
This page was actually created a number of years ago for another website site, but was never posted. It was lost in amongst numerous other uncompleted ideas, until today (Feb 10, 2007) when I happened to come across it. Terms were collected from numerous places on the Internet and from a number of computer manuals.

  • 10Base-T An IEEE Ethernet standard for 10Mbps data transmission using unshielded twisted pair wires
  • 100Base-Tx An IEEE Ethernet standard for 100Mbps data transmission using two pairs of Category 5 UTP wire
  • 1000Base-Tx An IEEE Ethernet standard for 1000Mbps data transmission using four pairs of Category 6 UTP wire
  • 802.11b An IEEE standard for wireless networking standard specifying a maximum data transmission rate of 11Mbps using DSSS modulation and an operating frequency of 2.4GHz.
  • 802.11g A draft standard proposed by IEEE that is awaiting ratification, to be an extension of the IEEE 802.11 standard. It specifies a data transfer rate of 54Mbps using ODFM modulation and an operating frequency of 2.4GHz, as well as backward compatibility with the 802.11b devices.
  • Auto MDI/MDI-X An Auto MDI/MDI-X port automatically senses the inserted cable type for transmission, and thus eliminates the need for crossover cables.
  • Bit Short for "Binary Digit." It uses 0 and 1 as the value for the binary numbering system. It is also the smallest form of data.
  • Browser a general name given to applications designed to view and interact with HTML pages on the World Wide Web.
  • CAT 5 a standard developed by the Electronics Industries Association that specifies network cabling which consists for twisted pairs of copper wire with a sustainable data rate of 100Mbps.
  • Database a collection of information that is organized so that the contents may be easily accessed/managed. Data Packet In an IP network, packet switching is the method employed to transmit data and the smallest chunk of data is called a packet (packet size can vary).
  • DHCP (Dynamic Host Configuration Protocol) a protocol that allows the network administrator to centrally manage and assign IP addresses to devices in the network. For more information on DHCP, please refer to the DHCP Technology Primer found on the Product CD.
  • DMZ (De-Militarized Zone) hosting allows the administrator to expose a private IP address onto the Internet. It is used for a PC/Server assigned with a Static IP address which has to run specialized applications requiring multiple TCP/IP ports to be opened.
  • DNS )Domain Name System) translates Internet domain names to IP addresses, giving meaningful and easy-to-remember names to otherwise arcane IP addresses.
  • Driver A piece of software developed to interface a piece of hardware with its immediate upper-layer software (i.e. operating system) so that it Learn more from our DHCP Technology Primer can be recognized and operated.
  • DSSS (Direct Sequence Spread Spectrum) is a modulation scheme employed by the 802.11b standard that uses a chipping code (redundant bit) during its transmission to reject interference.
  • Dynamic IP Address an IP address that is dynamically allocated or assigned to a client device within a TCP/IP network, typically by a DHCP server. Dynamic IP addresses generally change every so often.
  • Encryption a security method applying specific algorithms to make sure that all the data from one computer is encoded into a form that only the other intended party will be able to decode and view the information.
  • Ethernet An IEEE standard network protocol that specifies how data is transmitted over a common medium. It uses CSMA/CD which stands for Carrier Sense Multiple Access with Collision Detection. It originally had a defined data rate of 10Mbps, however 100Mbps and 1000Mbps networks are now common.
  • Fast Ethernet An IEEE standard extended from 10Base-T Ethernet to support 100Mbps data rate.
  • Firewall software layer, sometimes built into hardware devices, that controls network access from within and without so that any undesired activity may be prevented by malicious or snooping parties.
  • Firmware a software code written and saved within the read-only memory (ROM) or programmable read-only memory (PROM). The firmware that is written on the ROM/PROM is retained even when the device is powered off.
  • FTP (File Transfer Protocol) a protocol designed to transfer files over a TCP/IP network.
  • Full Duplex defines the ability of a device to transmit data simultaneously in both upstream and downstream directions over a single line.
  • Gateway a device that interconnects networks.
  • Half Duplex defines the ability of a device to transmit in one direction at a time over a single line.
  • HTTP (HyperText Transport Protocol) is a common protocol used to connect servers on the World Wide Web, with its primary function being to establish a connection with a web server and transmit HTML pages to the client’s browser.
  • ICMP (Internet Control Message Protocol) a message control and error reporting protocol between a host server and a gateway to the Internet. ICMP uses Internet Protocol (IP) datagrams, but the messages are processed by the IP software and are not directly apparent to the application user.
  • IGMP (Internet Group Management Protocol) is the standard for IP multicasting on the Internet. It is used to establish host memberships in particular multicast groups on a single network. The mechanisms of the protocol allow a host to inform its local router, using Host Membership Reports, that it wants to receive messages addressed to a specific multicast group. All hosts conforming to level 2 of the IP multicasting specification require IGMP.
  • IEEE the Institute of Electrical and Electronic Engineers. The IEEE is a professional technical body promoting the development and application of technology. This is the world group that sets most of the standards used in computer systems and many other electrical devices.
  • IP Address (Internet Protocol) a 32-bit binary digit that defines each sender or receiver of information across an IP network.
  • IPSec (Internet Protocol Security) is a suite of protocols used to implement secure exchange of packets at the IP layer.
  • ISP (Internet Service Provider) is a company that provides individuals or corporations with Internet access and other related services.
  • LAN (Local Area Network) a group of computers and devices sharing a common communication medium within a small geographical area.
  • Latency Latency is a time-delay.
  • MAC Address (Media Access Control) The MAC address is a unique number assigned by the manufacturer to any Ethernet networking device, such as a network adapter or router, that allows a network to identify the hardware. Unlike IP addresses, this number is permanent and is therefore a valuable identifier.
  • Mbps (Mega bits per second) a unit of measurement for data transmission indicating a million bits per second.
  • MDI (Medium Dependent Interface) On a network hub/switch, a MDI port (uplink port) connects to another hub/switch using a straight cable. To connect a MDI port to a computer, a crossover cable is used. MDI ports are no longer used in lieu of Ethernet
  • MDI-X (Medium Dependent Interface Crossed) On a network hub/switch, a MDI-X port connects to a computer using a straight cable. To connect a MDI-X port to another hub/switch, use a crossover cable.
  • MIME (Multipurpose Internet Mail Extensions) A standard format for use in e-mail systems which allows for attachments and much more.
  • NAT (Network Address Translations) multiplexes multiple private IP addresses for the LAN to a single public IP address on the Internet. For more information on NAT, please refer to the NAT Technology Primer on the Product CD.
  • OFDM (Orthogonal Frequency Division Multiplexing) a modulation scheme employed by the IEEE 802.11g standard, which combines numerous signals of different frequencies to form a single signal for transmission over a medium.
  • Packet Filtering a means of discarding unwanted network traffic based on its originating addresses or the type of data transmitted.
  • Ping Packet Internet Groper a utility used to determine whether a particular IP address is available online. It works by sending out a packet and waiting for a response from the recipient. Learn more from our NAT Technology Primer
  • PPPoE (Point-to-Point Protocol over Ethernet) is a method for the encapsulation of PPP packets over Ethernet frames.
  • RJ-45 A connector used for Ethernet devices which holds up to eight wires. It is interesting to note that RJ-45 is actually a standard defining the electrical and mechanical characteristics of the plug, and not the plug itself. However, it has become the norm to call the plug an RJ-45.
  • SNMP (Simple Network Management Protocol) a monitoring and controlling protocol. SNMP devices/applications report network activity within to a workstation console so that it may be monitored and controlled.
  • Subnet Mask a method of splitting IP networks into subgroups.
  • TCP (Transmission Control Protocol) enables two hosts to establish a connection and exchange streams of data, guaranteeing delivery of data and that packets will be delivered in the same order in which they were sent.
  • Throughput the measurable amount of data moved from one place to another within a given time period.
  • UDP (User Datagram Protocol) a communication protocol that, like TCP, runs on top of IP networks. Unlike TCP/IP, UDP provides a direct way to send and receive datagrams over an IP network and is used primarily for broadcasting messages over a network.
  • URL (Uniform Resource Locator) the address that defines the location of a file on the World Wide Web.
  • USB (Universal Serial Buss) a system of standards allowing electronic devices to communicate using standardized communication protocols
  • UTP (Unshielded Twisted Pair) is the most common kind of copper wiring designed to reduce crosstalk between copper wires.
  • VGA (Video Graphics Array) A monitor standard which has evolved into a term used to designate an image consisting of 640 pixels wide by 480 pixels tall.
  • VPN (Virtual Private Network) a secure means to join remote networks using comprehensive authentication and encryption. They may be “virtually” joined even across a public network like the Internet by means of employing IPSec amongst others.
  • WAN (Wide Area Network) a communication network that extends over a large geographical area.
  • WEP (Wired Equivalent Privacy) a wireless data privacy encryption protocol based on a 64-bit or 128-bit shared key algorithm.
  • WLAN (Wireless Local Area Network) a group of computers and associated devices that communicate with each other wirelessly.

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