Pertaining to the presence or absence of electronic or magnetic "signals" in the computers circuitry or in the media it uses. There are only two possible states or conditions - presence or absence.
Central Processing Unit (CPU):
The unit of a computer system that includes the circuits that controls the interpretation and execution of instructions. In many computer systems, the CPU includes the arithmetic-logic unit, the control unit, and primary storage unit.
Computer hardware as a system of input, processing, output, storage, and control components. Thus a computer system consists of input and output devices, primary and secondary storage devices, the central processing unit, the control unit within the CPU, and other peripheral devices.
Any input/output device connected by telecommunications links to a computer.
Digital still cameras and digital video cameras enable you to shoot, store, and download still photos or full-motion video with audio in your PC.
A method of storage where each storage position has a unique address and can be individually accessed in approximately the same period of time without having to search through other storage positions.
Downsizing computer platforms results from using networks of microcomputers to replace minicomputers and mainframes.
Generations of Computing:
Reflect stages in the development of electronic computers, characterized by major changes in technology or performance.
Devices for consumers to access the Internet.
A small portable PC.
Liquid Crystal Displays (LCD):
Electronic visual displays that form characters by applying an electrical charge to selected silicon crystals.
Magnetic Disk Storage:
Data storage technology that uses magnetized spots on metal or plastic disks.
Magnetic Disk Storage - Floppy Disk:
Small phonograph record enclosed in a protective envelope. It is a widely used form of magnetic disk media that provides a direct access storage capability for microcomputer systems.
Magnetic Disk Storage - Hard Disk
Secondary storage medium; generally nonremovable disks made out of metal and covered with a magnetic recording surface. It holds data in the form of magnetized spots.
Magnetic Disk Storage - RAID
Redundant array of independent disks. Magnetic disk units that house many interconnected microcomputer hard disk drives, thus providing large, fault tolerant storage capacities.
Magnetic Ink Character Recognition (MICR):
The machine recognition of characters printed with magnetic ink. Primarily used for check processing by the banking industry.
A plastic tape with a magnetic surface on which data can be stored by selective magnetization of portions of the surface.
A magnetic stripe card is a plastic wallet-size card with a strip of magnetic tape on one surface; widely used for credit/debit cards.
A larger-size computer system, typically with a separate central processing unit, as distinguished from microcomputer and minicomputer systems.
A very small computer, ranging in size from a "Computer on a chip" to a small typewriter-size unit.
A semiconductor chip with circuitry for processing data.
Larger and more powerful than most microcomputers but are smaller and less powerful than most large mainframe computer systems.
A small electronic general-purpose computer.
A new category of microcomputer designed mainly for use with the Internet and Intranets on tasks requiring limited or specialized applications and no or minimal disk storage.
Low-cost networked-enabled PCs with reduced features.
A type of midrange computer used to co-ordinate telecommunications and resource sharing and manages large web sites, Intranets, extranets, and client/server networks.
A terminal that depends on network servers for its software and processing power.
Pertaining to equipment or devices not under control of the central processing unit.
Pertaining to equipment or devices under control of the central processing unit.
Optical Character Recognition (OCR):
The machine identification of printed characters through the use of light-sensitive devices.
Optical Disk Storage:
Technology based on using a laser to read tiny spots on a plastic disk. The disks are currently capable of storing billions of characters of information.
Optical Disk Storage - CD-ROM:
An optical disk technology for microcomputers featuring compact disks with a storage capacity of over 500 megabytes.
Optical Disk Storage - CD-R:
Compact disk recordable (CD-R) enables computers with CD-R disk drive units to record their own data once on a CD, than be able to read the data indefinitely.
Optical Disk Storage - CD-RW:
Compact disk rewritable (CD-RW) enables computers with CD-RW disk drive units to record and erase data by using a laser to heat a microscopic point on the disks surface.
Optical Disk Storage - DVD:
Digital video disk or digital versatile disk (DVD) enables computers with DVD disk drive units to hold from 3.0 to 8.5 gigabytes of multimedia data on each side of a compact disk.
Optical Disk Storage - WORM Disk:
Optical disk that allows users to write once, read many times.
Using a device (scanner) that scans characters or images and generates their digital representations.
Tablet-style microcomputers that recognize hand-writing and hand-drawing done by a pen-shaped device on their pressure sensitive display screens.
In a computer system, any unit of equipment, distinct from the central processing unit, that provides the system with input, output, or storage capabilities.
Personal Digital Assistant:
Handheld microcomputer devices which are designed for convenient mobile communications and computing.
Devices, which allow end users to issue commands or make choices by moving a cursor on the display, screen.
Pointing Device - Electronic Mouse:
A small device that is electronically connected to a computer and is moved by hand on a flat surface in order to move the cursor on a video screen in the same direction. Buttons on the mouse allow users to issue commands and make responses or selections.
Pointing Device - Pointing Stick:
A small buttonlike device sometimes likened to the eraser head of a pencil. The cursor moves in the direction of the pressure you place on the track point.
Pointing Device - Touchpad:
Is a small rectangular touch-sensitive surface usually placed below the keyboard. The cursor moves in the direction your finger moves on the pad.
Pointing Device - Trackball:
A roller device set in a case used to move the cursor on a computers display screen.
The main (or internal) memory of a computer. Usually in the form of semiconductor storage.
Devices that produce hard copy output such as paper documents or reports.
External or auxiliary storage device that supplements the primary storage of a computer.
Microelectronic storage circuitry etched on tiny chips of silicon or other semiconducting material.
Semiconductor Memory - RAM:
Also known as main memory or primary storage; type of memory that temporarily holds data and instructions needed shortly by the CPU. RAM is a volatile type of storage.
Semiconductor Memory - ROM:
Also known as firmware; a memory chip that permanently stores instructions and data that are programmed during the chips manufacture. Three variations on the ROM chip are PROM, EPROM, and EEPROM. ROM is a non-volatile form of storage.
A sequential method of storing and retrieving data from a file.
Cards such as debit and credit cards, which have an embedded microprocessor chip and several kilobytes of memory.
Direct conversion of spoken data into electronic form suitable for entry into a computer system. Promises to be the easiest, most natural way to communicate with computers.
Storage Capacity Elements:
Units used for storage capacity and data: bits, bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB).
Storage Capacity Elements - Bit:
A contraction of "binary digit". It can have the value of either 0 or 1.
Storage Capacity Elements - Byte:
A sequence of adjacent binary digits operated on as a unit and usually shorter than a computer word. In many computer systems, a byte is a grouping of eight bits that can represent one alphabetic or special character or can be "packed" with two decimal digits.
Storage Capacity Elements - Kilobyte (K or KB):
When referring to computer storage capacity it is equivalent to 2 to the 10th power, or 1,014 in decimal notation.
Storage Capacity Elements - Megabyte (MB):
One million bytes. More accurately, 2 to the 20th power, 1,048,576 in decimal notation.
Storage Capacity Elements - Gigabyte (GB):
One billion bytes. More accurately, 2 to the 30th power, or 1,073,741,824 in decimal notation.
Storage Capacity Elements - Terabyte (TB):
One trillion bytes. More accurately, 2 to the 40th power, or 1,009,511,627,776 in decimal notation.
Storage Media Trade-offs:
The trade-offs in cost, speed, and capacity of various storage media.
A special category of large computer systems that are the most powerful available. They are designed to solve massive computational problems.
Units used for measuring processing speeds: milliseconds, microseconds, nanoseconds, and picoseconds.
Time Elements - Millisecond:
A thousandth of a second.
Time Elements - Microsecond:
A millionth of a second.
Time Elements - Nanosecond:
One billionth of a second.
Time Elements - Picosecond:
One trillionth of a second.
An input device that accepts data input by the placement of a finger on or close to the CRT screen.
Trends in Computers:
Smaller, faster, and cheaper.
Video displays are the most common type of computer output.
Memory (such as electronic semiconductor memory) that loses its contents when electrical power is interrupted.
A handheld optical character recognition device used for data entry by many transaction terminals.
A computer terminal or micro- or minicomputer system designed to support the work of one person. Also, a high-powered computer to support the work of professionals in engineering, science, and other areas that require extensive computing power and graphics capabilities.