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Computer terms-part-6

computer hardware










Computer terms-part-6

Hard copy
The printed output generally on paper, that can be taken away and studied.
HARD ERROR:
An error that is caused by some malfunction in the hardware. For example, a disk head is incorrectly reading the information on the disk.
Hardware:
Refers to all the equipment that make up the computer system.  If it can be picked up and carried them it is hardware as opposed to software.
Hardwired:
Refers to a type of modem.  It ends its signals directly down the telephone line instead of sending impulses through an acoustic coupler and then through the telephone handset.
Hashing:
Refers to any technique that transforms one or more fields in a record into a more compact field.
Hash total
It is the sum that is obtained by adding the values in a particular field and comparing it to the sum obtained in the same manner at an earlier stage, in order to check for errors.
Hazard:
It refers to a potential or actual malfunction of a log circuit during changes of state of input variables.
Head:
It is the assembly that contains the electromagnets hat read and write to a tape, floppy disk etc.
Head crash:
refers to the crashing of the disk when the read-write head of the disk drive touches the surface of the disk. it generally results in a permanent damage at the point of impact.
Header
Refers to those programs that have the ability to print material to paper will automatically print and identifying line at the top of each page. It also usually numbers automatically each page.
Help
A function that is available on many systems, it can make available to the user information on points that need further explanation.
Hercules adapter:
A software system that can display graphics at high resolutions on a monochrome monitor.
Hertz
It is the standard unit of frequency.   1 hertz=1 cycle per second(cps)
Heuristic:
It refers o a rail and error approach of problem-solving. This involves inference and most likely choices rather than the manipulation of absolute logic. It offers a solution which is good enough most of the time.
Identification division:
One of the four divisions of a COBOL program.  In the identification division, the programmer provides descriptive information that identifies the program being compiled.
identifier
A label identifying a file of data held on an input or output device, or identifying a particular location in store.
Idle characters
Characters that are used in data communication to synchronize the translation.
Idle time
Refers to the time during which a computer though available but not in use.
I.D.P.M.
Institute of Data Processing Management.
If-then-else
A programming instruction that specifies a set of instructions to be carried out under certain conditions.  For example, if “x-o,” then x-o is the condition that determines what will happen next, and the computer will be directed to branch to the appropriate statement.
Illegal character
A bit arrangement that is not recognized as a specific character in a given computer.
Image:
An exact copy of an area of the store that is located in another part of the store or in a different storage medium.
Image processing:
The processing of digital data that represent a picture which may be a painting, photograph etc.  It is possible to change selected parts of the picture at the will of the user.
Immediate access:
a store wherein information can be retrieved without significant delay.
Immediate access store
Refers to those memories where data can be accessed in times of one million of a second or less.  It includes the sores within the central processor and also those directly addressable by the programmer.
Impact printer:
A type of printer that forms characters by striking an element on an ink-bearing ribbon and in this way printing a character on the paper e.g. Dot-matrix printer, daisy wheel printers.
implementation
Those procedures which are involved in installing and testing hardware and software in computer systems.
Increment
It is the amount added o a value or variable.
Incremental plotter
It is a device that can draw graphs and other line images when fed with digital data.  It forms the image by moving a pen or the paper or both in a succession of increment which is typically 200 per inch in case of drum plotter and 500 per inch in case of the flatbed plotter.
index
It I the table that contains the keys in the record in a file and the location where they are stored. Indexed Address it refers to an address that is modified by the content of an index register before or during the execution of a computer instruction.
Index hole
It is a hole that is provided in a floppy disk to mark the beginning of each track on a soft sectored disk or to mark the beginning of each sector on a hard sectored disk. The electro-graphical system provided in the disk drive can sense this hole.
indexing
A method that is used to retrieve information from a table in memory or a file on a direct access store.
Index register
In some computers program modification is carried out automatically and indeed it may be always used to adder certain locations within the memory. In such machines, there will be at least one index register which will be having a modifier to enable data to be indirectly addressed. Each program instruction must, therefore, refer to an index register when addressing locations in sore.  It is sometimes called a modifier register.
indicator
1. A lamp or display device on a peripheral unit or a console
2. A device that can be set when a specified condition occurs(e.g. when a calculation has produced a negative result) and which may be tested by the program for initiating an appropriate course of action.
Indirect addressing
A programming technique wherein the address part of an instruction refers to another location that has another address.  This further address may specify an operand or yet another address.  It is also called multi-level addressing.
Infix notation
A notation that is used for representing logical operations in which the operator is written between the operands. E.g. A and B where represents the operation ‘and’.
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