A memory chip that maintains its contents without electrical power, and whose contents can be erased and reprogrammed either within the computer or from an external source. EEPROMs are used where the application requires stable storage without power, but where the chip may have to be reprogrammed.
Any electromagnetic radiation released by an electronic device that disrupts the operation or performance of any other device.
embedded controller The general class of microcontrollers used to support OEM-specific implementations, mainly in mobile environments. The embedded controller performs complex low-level functions through a simple interface to the host microprocessor(s).
embedded controller interface ACPI defines a standard hardware and software communications interface between an operating system driver and an embedded controller--for example, Smart Battery and AML code. This allows any operating system to provide a standard driver that can directly communicate with an embedded controller in the system, thus allowing other drivers to communicate with and use the resources of system embedded controllers.
A device built to work exactly like another device, either hardware, software, or a combination of both.
The file format of the PostScript page description language. The EPS standard is device independent, so that images can easily be transferred between different applications, and they can be sized and output to different printers without any loss of image quality or distortion.
The process of encoding information in an attempt to make it secure from unauthorized access. The reverse of this process is known as decryption.
Refers to the person who uses the application program to produce their own results.
A video adapter standard that provides medium-resolution text and graphics, introduced by IBM in 1984. EGA can display 16 colors at the same time from a choice of 64, with a horizontal resolution of 640 pixels and a vertical resolution of 350 pixels.
A popular hard disk, floppy disk, and tape drive interface standard, capable of a data transfer rate of 10 to 20 megabits per second. ESDI is most often used with large hard disks.
enhanced television Combines standard television with HTML information related to programs.
A computer system that meets the basic requirements for a specific task. As computers become both cheaper and more capable, the definition of an entry-level system changes. Also, application developers continue to create new and more complex programs, which in turn demand more capability from the hardware.
enumeration The process by which logical devices and buses, and their available resources, are identified by Plug and Play during system setup.
enumerator A Plug and Play device driver that detects devices below its own device node, creates unique device IDs, and reports to Configuration Manager during startup. For example, a SCSI adapter provides a SCSI enumerator that detects devices on the SCSI bus.
A memory chip that maintains its contents without electrical power, and whose contents can be erased and reprogrammed by removing a protective cover and exposing the chip to ultraviolet light.
error detection and correction
A mechanism used during a file transfer to determine whether transmission errors have occurred, and to correct those errors, if possible. Some programs or transmission protocols request a retransmission of the affected block of data if such an error is detected. More complex protocols attempt to both detect and correct transmission errors.
A LANcabling technology that uses CSMA/CD delivery. Ethernet runs over many different media, ranging from thick cable (10Base5) to twisted-pair wire (10BaseT). Ethernet has been standardized by the International Electrical and Electronics Engineers (IEEE) organization. The three most common Ethernet cabling standards are:
Thick Ethernet (10Base5)
This is the original Ethernet cabling which used a thick, half -inch diameter coaxial cable. It operates in baseband mode with a bandwidth of 10Mbps. The maximum cable length of a segment is 500 meters. The IEEE label 10Base5 summarizes these characteristics:10-Mbps bandwidth, baseband operation, and 500 meter segments.Thick Ethernet uses MAUs(multistation access units), N-type, and AUI (attachment unit interface) connectors.
Is a CSMA/CD network with these features: 10-Mbps bandwidth, baseband operation, and segment lengths of approximately 200 meters(the exact limit is 185 meters). The coaxial cable used is considerably thinner than thicknet coax. Thin Ethernet uses BNC (bayonet) and T connectors.
The hardware address that identifies the Ethernet network interface card inside a computer. Also called the physical address. No two Ethernet addresses are identical.
event set A uniquely identified set that represents a group of items about which a client can be notified.
1 quadrillion bytes or 1,152,921,504,606,846,976 bytes.
The ability of a system to accommodate expansion. In hardware, this may include the addition of more memory, more or larger disk drives, and new adapters, and in software may include the ability of a network to add users, nodes, or connections to other networks.
A DOS mechanism by which applications can access more than the 640KB of memory normally available to them.
The Expanded Memory Specification LIM 4.0 is the standard method of accessing expanded memory, and lets programs running on any of the Intel 8086 family of processors access as much as 32MB of expanded memory. The expanded memory manager creates a block of addresses into which data (held in memory above the 1 MB limit) is swapped in and out as needed by the program. In other words,a 64K segment of addressable memory creates a small window through which segments of expanded memory can be seen, but only one segment at a time.
The original version of the Lotus-Intel-Microsoft Expanded Memory Specification (LIM EMS), that lets DOS applications use more than 640KB of memory space.
An extension of the main computer bus that includes expansion slots for use by compatible adapters, such as including memory boards, video adapters, hard disk controllers, and SCSI interface cards.
One of the connectors on the expansion bus that gives an adapter access to the system bus. The amount of additional adapters that one may add is determined by how many expansion slots are inside your computer.
An external housing available with certain portable computers designed to contain additional expansion slots and maintain a connection to the main expansion bus in the computer's system unit.
extended ASCII character set
The second part of the ASCII character set from decimal code 128 to decimal code 255. This part of the ASCII character set is not standard, and will contain different characters on different types of computer.
ECP Extended capabilities port. An asynchronous, 8-bit-wide parallel channel defined by IEEE 1284-1944 that provides PC-to-peripheral and peripheral-to-PC data transfers.
extended DOS partition
A further optional division of a hard disk, after the primary DOS partition, that functions as one or more additional logical drives. A logical drive is simply an area of a larger disk that acts as though it were a separate disk with its own drive letter. Creating an extended partition allows you to install a second operationg system, such as OS/2; and in early DOS versions it is the only way to use disk space above 32MB. NOTE:DOS partitions are created and changed using the FDISK command.
Radiation emitted by a computer monitor and other very common household electrical appliances such as televisions, hair dryers, electric blankets and food processors.
ELF emissions fall into the range from 5Hz to 2000Hz, and decline with the square of the distance from the source. Emissions are not constant around a monitor; they are higher from the sides and rear, and weakest from the front of the screen. Low-emission models are available, and laptop computers with an LCD display do not emit any ELF fields.