Modulation is the addition of information (or the signal) to an electronic or optical signal carrier. Modulation can be applied to direct current (mainly by turning it on and off), to alternating current, and to optical signals. One can think of blanket waving as a form of modulation used in smoke signal transmission (the carrier being a steady stream of smoke). Morse code, invented for telegraphy and still used in amateur radio, uses a binary (two-state) digital code similar to the code used by modern computers.
Short for Transmission ControlProtocol/Internet Protocol, the suite of communication protocals used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operatiing system and is used by the Internet.
A server is primarily a program that runs on a machine, providing a particular and specific service to other machines connected to the machine on which it is found.
Abbreviated as NOS, an operating system that includes special functions for connecting computers and devices into a local-area network (LAN). Some operating systems, such as UNIX and the Mac OS, have networking functions built in. The term network operating system, however, is generally reserved for software that enhances a basic operating system by adding networking features. Novell Netware, Artisoft's LANtastic, Microsoft Windows Server, and Windows NT are examples of an NOS.
A Network Administrator is a professional in charge of the maintenance of the computer hardware and software systems that make up a computer network. This includes activities such as the deployment, configuration, maintenance and monitoring of active network equipment.
A portion of RAM used to speed up access to data on a disk. The RAM can be part of the disk drive itself or it can be general-purpose RAM in the computer that is reserved for use by the disk drive. Hard disk caches are more effective, but they are also much more expensive, and therefore smaller.
File compression is commonly used when sending a file from one computer to another over a connection that has limited bandwidth. The compression basically makes the file smaller and, therefore, the sending of the file is faster. Of course, when compressing a file and sending it to another computer that computer has to have a program that will decompress the file so it can be returned to "normal" and used.
Many of the files on the Engineering Service Center FTP (file server) site are "compressed." To facilitate decompressing these files, we have made many decompression programs available. Every effort is made to ensure that all compression programs have a decompression program available here for Macintosh, Windows, DOS and UNIX based workstations. Please read the file descriptions below and FTP (download) the appropriate file(s).
In computing, an optical disc drive (ODD) is a disk drive that uses laser light or electromagnetic waves near the light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from discs, but recent drives are commonly both readers and recorders. Recorders are sometimes called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives.
Abbreviated SSD, a solid state disk is a high-performance play storage that contains no moving parts. SSD components include either DRAM or EEPROM memory boards, a memory bus board, a CPU, and a battery card.
A type of printer that works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path direct the ink onto the paper in the desired shapes. Ink-jet printers are capable of producing high quality print approaching that produced by laser printers. A typical ink-jet printer provides are solution of 300 dots per inch although some newer models offer higher resolutions.
A type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work.
In computing, a technique that enables special characters printed in magnetic ink to be read and input rapidly to a computer. MICR is used extensively in banking because magnetic-ink characters can be machine-read with much greater accuracy than human reading or Optical Character Recognition (OCR) systems, and are therefore ideal for marking and identifying the account and sort code numbers on cheques.
Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate (for example, into ASCIIcodes). An OCR system enables you to take a book or a magazine article, feed it directly into an electronic computer file, and then edit the file using a word processor.
Optical Mark Recognition (OMR) is the technology of electronically extracting intended data from marked fields, such as checkboxes and fill-in fields, on printed forms. It is generally distinguished from OCR by the fact that a recognition engine is not required. This requires the image to have high contrast and an easily-recognizable or irrelevant shape. OMR technology scans a printed form and reads predefined positions and records where marks are made on the form. This technology is useful for applications in which large numbers of hand-filled forms need to be processed quickly and with great accuracy, such as surveys, reply cards, questionnaires and ballots.
ROM
Graphic Card
A video card, video adapter, graphics accelerator card, display adapter, or graphics card is an expansion card whose function is to generate output images to a display. Most video cards offer added functions, such as accelerated rendering of 3D scenes and 2D graphics, video capture, TV-tuner adapter, MPEG-2/MPEG-4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors (multi-monitor). Other modern high performance video cards are used for more graphically demanding purposes, such as PC games.
Sound card
An expansion board that enables a computer to manipulate and output sounds. Sound cards are necessary for nearly all CD-ROMs and have become commonplace on modern personal computers. Sound cards enable the computer to output sound through speakers connected to the board, to record sound input from a microphone connected to the computer, and manipulate sound stored on a disk.
Nearly all sound cards support MIDI, a standard for representing music electronically. In addition, most sound cards are Sound Blaster-compatible, which means that they can process commands written for a Sound Blaster card, the de facto standard for PC sound.
Network interface card
A network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network. Personal computers and workstations on a local area network (LAN) typically contain a network interface card specifically designed for the LAN transmission technology, such as Ethernet or token ring. Network interface cards provide a dedicated, full-time connection to a network. Most home and portable computers connect to the Internet through as-needed dial-up connection. The modem provides the connection interface to the Internet service provider.
Plug And Play
Plug and Play (PnP) is a capability developed by Microsoft for its Windows 95 and later operating that gives users the ability to plug a device into a computer and have the computer recognize that the device is there. The user doesn't have to tell the computer. In many earlier computer systems, the user was required to explicitly tell the operating system when a new device had been added. Microsoft made Plug and Play a selling point for its Windows operating systems. A similar capability had long been built into Macintosh computers.
An Asynchronous port on the computer used to connect a serial device to the computer and capable of transmitting one bit at a time. Serial ports are typically identified on IBM compatible computers as COM (communications) ports. For example, a mouse might be connected to COM1 and a modem to COM2. With the introduction of USB, FireWire, and other faster solutions serial ports are rarely used when compared to how often they've been used in the past. To the right is a close up of a DB9serial port on the back of a computer.
A parallel interface for connecting an external device such as a printer. Most personal have both a parallel port and at least one serial port.
On PCs, the parallel port uses a 25-pin connector (type DB-25) and is used to connect printers, computers and other devices that need relatively high bandwidth. It is often called a Centronics interface after the company that designed the original standard for parallel communication between a computer and printer. (The modern parallel interface is based on a design by Epson.)
A USB port is a standard cable connection interface on personal computers and consumer electronics. USB ports allow stand-alone electronic devices to be connected via cables to a computer (or to each other).USB stands for Universal Serial Bus, an industry standard for short-distance digital data communications. USB allows data to be transferred between devices. USB ports can also supply electric power across the cable to devices without their own power source.
Firewire ports are forms of a serial port that make use of FireWire technology to transfer data rapidly from one electronic device to another. The FireWire port has been in common use since 1995, when Apple, Inc. first began to include the port on a number of digital camcorders. Today, the FireWire port is used on a number of other devices.
As a multi-platform serial bus, the FireWire port has the ability to interact with a number of different devices. For example, a FireWire connection can provide an ideal way to connect a scanner to a computer system. Because the transfer rate of a FireWire port can reach up to 400Mbps, the data transfer is relatively fast and also results in excellent quality.
An Ethernet port is an opening on computer network equipment that Ethernet cables plug into. These ports are alternatively called jacks or sockets. Ethernet ports accept cables with RJ-45 connectors.
HDMI
HDMI (High-Definition Multimedia Interface) is an industry standard for creating audio and video connections between high-definition electronic devices. HDMI supports two-way digital communication between the video source and the video display with one cable. The simple cabling scheme has made HDMI popular for home theatre setups.