Input & Output
13 years ago
Modulation
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.
Demodulation
The process of separating the original information or signal from the modulated career. In the case of amplitude or frequency modulation it involves a device, called a demodulator or detector, which produces a signal corresponding to the instantaneous changes in amplitude or frequency, respectively. This signal corresponds to the original modulating signal
Bandwidth
In computer networks, bandwidth is often used as a synonym for data transfer rate - the amount of data that can be carried from one point to another in a given time period (usually a second). This kind of bandwidth is usually expressed in bits (of data) per second (bps). Occasionally, it's expressed as bytes per second (Bps). A modem that works at 57,600 bps hastwice the bandwidth of a modem that works at 28,800 bps. In general, a link with a high bandwidth is one that may be able to carry enough information to sustain the succession of images in a video presentation.
TCP/IP
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.
Node
In a network, a node is a connection point, either a redistribution point or an end point for data transmissions. In general, a node has programmed or engineered capability to recognize and process or forward transmissions to other nodes.
Client
A client is the requesting program or user in a client/server relationship. For example, the user of a Web browser is effectively making client requests for pages from servers all over the Web. The browser itself is a client in its relationship with the computer that is getting and returning the requested HTML file. The computer handling the request and sending back the HTML file is a server.
Server
Nowadays, server functionality has become so rich, complex and varied in nature that there are whole very powerful computers dedicated to being exclusively servers. This has led many non-technical people to denote servers as being machines that run services.
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.
Network operating system
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.
Network administrator
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.
Disk Caching
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.
File decompression
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).
Internet hard drive
The sole purpose of an Internet hard drive is to offer a means of accessing your computer files (pictures, documents, music, videos, etc.) from any computer, as long as that computer has access to the internet. Similar to depositing money into your bank account, and later withdrawing that same money from any ATM machine, an Internet hard drive will allow you to "deposit" your computer files into a remote hard drive, and then later access those very same files from any other computer.
Optical disc drive
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.
Solid state storage
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.
Ergonomic Keyboard
Ergonomic keyboard designs also help to relieve sometimes painful conditions such as Capra tunnel syndrome and repetitive stress injury that results from extended keyboard usage. These specially designed, contoured keyboards are created with comfort in mind, and are often recommended by therapists and health care professionals.The ergonomic keyboard was designed to to relieve some of that stress and provide a more comfortable platform for typing.
Inkjet Printer
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.
Laser Printer
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.
Magnetic-ink character recognition
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.
Optical character recognition
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
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.
RAM means Random Access Memory, it's a type of comouter memory that can be accessed randomly. Any byte of memory can be accessed without touching the preceding bytes. Ram is one of the most common type of memory found in computers and other devices such as printers. There are two types of of RAM. DRAM means Dynamic Random Access Memory and SRAM is Static Random Access Memory. The difference between both of this is that the techonology they use to hold data, with DRAM being more common type. In terms of speed, SRAM is faster. DRAM needs to be refreshed per second but SRAM does not need to be refreshed which is what makes it faster than DRAM.
CACHE
ROM
A cpu cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. When the processor neeeds to read from or write a location in main memory, it first checks whether a copy of that data is in the cache . If so, the processor immediately reads from ot writes to the cache, which is much faster than reading from or writting to main memory.
ROM means read only memory, computer memory on which data has been prerocorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read. Unlike main memory, ROM retains its contents even when the computer is turned off. ROM is reffered to be as being nonvolatile, whereas RAM is volatile.
FLASH MEMORY
Flash memory (sometimes called "flash RAM") is a type of constantly-powered non-volatile memory that can be erased and reprogrammed in units of memory called blocks. It is a variation of electrically erasable programmable read-only memory (EEPROM) which, unlike flash memory, is erased and rewritten at the byte level, which is slower than flash memory updating. Flash memory is often used to hold control code such as the basic input/output system (BIOS) in a personal computer. When BIOS needs to be changed (rewritten), the flash memory can be written to in block (rather than byte) sizes, making it easy to update. On the other hand, flash memory is not useful as random access memory (RAM) because RAM needs to be addressable at the byte (not the block) level.
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.
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