A word is the computer's internal storage unit and refers to the amount of data it can hold in its registers and process as a single unit. For example, a 16-bit computer processes two bytes in the same time it takes an 8-bit computer to process one byte, providing the timing clocks are of equal speed.
A blog About Computer Science and has many topics or post related to networking, hardware, software and more about in Computer science.
Tuesday, February 25, 2014
What is WORM
WORM stands for Write Once Read Many. A storage disk that is more easily written than CD-ROM, making single copy disks commercially feasible.
What is word length
A measure of the size of a word, usually specified in units such as characters or bits. Each location of a computer system can store a fixed number of characters or bits called its word length.
What is Wafer
A wafer is a round slice of a silicon approximately 1/30th of an inch thick and form three to six inches in diameter that is the base unit upon which hundreds of chips are created through a series of photo-masking, etching and implementation steps.
What is Volatile Memory
A memory in which a constant electrical power source is required to maintain the contents of memory. If the power is switched off, the stored information is lost.
What is VLSI
VLSI stands for Very Large Scale Integration. An electronic circuit with about 10,000 transistors fabricated in a single silicon chip.
What is Virtual System
An extension of virtual storage concept. With virtual systems, users can share all of the computer resources as if each user hard his own computer.
What is Virtual Memory
The technique of using disk space to make programs believe that the system contains more random access memory (RAM) than is actually available. This can be implemented by using pure segmentation, pure paging, or a combination of both.
Monday, February 24, 2014
What is Video Display Unit (VDU)
An I/O device that consists of a television-like screen for displaying outputs and a keyboard for entering inputs.
What is USRT
USRT stands for Universal Synchronous Receiver Transmitter. A USRT is an electronic circuit that converts parallel bits to serial bits and vice versa. Inside the computer, data is worked on in parallel (8 or more bits at a time), whereas transmission over a communications channel is serial (one bit following the other). The USRT is also responsible for generating timing for synchronous transmission.
Who is User
Any individual who supplies input data to, or uses information generated by a computer based system.
What is Unix
A popular operating system for 16-bit mini and micro computers that was designed by Bell Telephone Laboratories, USA.
What is UNIVAC
An acronym for Universal Automatic Computer. It was the first commercially available computer.
What is Unconditional Jump
A jump that takes place whenever the instruction that specified it is executed.
What is UART
UART stands for Universal Asynchronous Receiver Transmitter. A UART is an electronic circuit that converts parallel bits to serial bits and vice versa. Inside the computer, data is worked on in parallel (8 or more bits at a time), whereas transmission over a communications channel is usually serial (one bit following the other). The serial transmission is asynchronous, which means the UART is responsible for generating and detecting the start and stop bits that accompany each character transmitted.
What is Two's Complement Representation
Used to represent binary numbers. A positive number is represented as in sign-magnitude. A negative number is represented by adding one of the one's complement representation of the same number.
What is Truth Table
A truth table defines all the input and outputs of a logical condition. The following example is a truth table for the Boolean AND operation -
Inputs Outputs
------------ --------------
1 AND 1 1
1 AND 0 0
0 AND 1 0
0 AND 0 0
Inputs Outputs
------------ --------------
1 AND 1 1
1 AND 0 0
0 AND 1 0
0 AND 0 0
What is Time Sharing
Refers to the allocation of computer resources in a time-dependent fashion to several programs simultaneously. It enables a large number of users to simultaneously use a computer for processing their jobs which may be of different nature.
What is Thrashing
The state of a virtual memory system that is spending almost all its time swapping pages in and out of memory rather than executing applications.
What is Third Generation Computer
Computer built between 1964 and 1975 that used integrated circuits (ICs) in CPU, high speed magnetic core main memories, powerful high level languages and saw the advent of time sharing operating system.
What is System Software
A set of one or more programs designed to control the operation of a computer system. They are general programs written to assist humans in the use of computer system more effective and efficient.
What is Syntax Error
Errors in computer programs that typically involve incorrect punctuation, incorrect word sequence, undefined terms, or misuse of terms. These errors are automatically detected and pointed out by language processors.
What is Synchronous Time
A technique in which the occurrence of events on a bus is determined by a clock. The clock defines equal-width time slots, and events begin only at the beginning of a time slot.
What is Subscript
In word processing and mathematical notation, a subscript is a digit or symbol that appears below the line. Contrast with superscript which is a symbol that appears above line. For example, H20 has 2 as subscript.
What is Stored Program Computer
A computer where the program to solve a problem and the necessary data are stored in its memory.
What is Static RAM
A RAM whose cells are implemented using flip flops. A static RAM will hold data as long as the power is supplied to it. No periodic refreshment is required.
What is Stack
A stack is a set of hardware registers or a reserved amount of main memory that is used for arithmetic calculations or for keeping track of internal operations. Stacks are used to keep track of the sequence of routines that are called in a program. Stacks usually work on a last-in-first-out basis in order to accomplish this. The last item, or address, placed (pushed) onto the stack is the first item removed (popped) from the stack.
What is Stack Pointer
A stack pointer is the address that identifies the location of the most recent item placed on the stack.
What is Spooling
A technique that has been successfully used on a number of computer systems to reduce the speed mismatch between slow speed I/O devices and fast CPU.
What is Software
The set of computer Programs, procedures, and associated documentation related to the effective operation of a computer system.
What is Soft Copy
Soft copy is data temporarily displayed on a video screen. Contrast with hard copy, which is printed output from the printer.
What is Sign-Magnitude Representation
Used to represent binary number's. In an N-bit word, the leftmost bit is the sign (0 = positive, 1 = negative) and the remaining N-1 bits comprise the magnitude of the computer.
Shell
A shell is an outer layer of a program that provides the user interface, or a way of commanding the computer. Shells are typically add on programs created for command driven operating systems, such as UNIX and Microsoft's DOS. The shell provides a menu driven or graphical icon oriented interface to the system in order to make it easier to use.
In other words, the shell is an executable file which is responsible for interpreting commands and transmitting them to the system and returning the result. Shell is used for interactive or non interactive commands. In interactive mode they accept input type from the keyboard when executing non interactive, shell execute commands read from a file.
In other words, the shell is an executable file which is responsible for interpreting commands and transmitting them to the system and returning the result. Shell is used for interactive or non interactive commands. In interactive mode they accept input type from the keyboard when executing non interactive, shell execute commands read from a file.
What is Serial And Parallel Port
A serial and parallel port is one serial and one parallel connector for connecting peripheral devices to your personal computer. Personal computers are often advertised as having a serial and parallel port. Although more than one of each may be necessary for a particular requirement, the serial port allows you to hook up a modem, mouse or printer, and the parallel port lets you hook up a printer.
What is Sequential Circuit
A digital logic circuit whose output depends on the current input plus the state of the circuit. Mostly, flip-flops are involved in sequential circuits.
What is Semiconductor
A semiconductor is a solid state substance that can be electrically altered. Certain elements in nature, such as silicon, perform like semiconductors when they are chemically combined with other elements. A semiconductor is halfway between a conductor, a material that conducts electricity, and an insulator, a material that resists conduction of electricity.
What is Semantics
Semantics is the study of the meanings of words. As applied to computer languages, semantics governs the basic rules of the language. For example, a reserved word, such as DISPLAY or LIST, should not be used as the name of a data file or field so that you do not wind up with LIST LIST. Contrast with syntax, which deals with the correct order or symbols used in combining words in a command phrase.
What is Segmentation
A method of providing virtual memory. A multidimensional linear address space implementation differentiates this from paging.
What is Second Generation Computer
Computer built during the period 1955-64 which used transistors in CPU, magnetic core main memories, and high level languages like FORTRAN and COBAL for programming.
What is Response Time
The total time elapsed between submission of command and data to a computer and getting the result of computation.
What is Resident Program
A program that remains in the memory while other programs are executing. The PC Local Area Network program is a collection of resident programs.
What is Relative Address
A relative address is an address that is relative to the first location of the program rather than a fixed location of memory. The relative address is added to the base address in order to derive the absolute address, the actual current location of the data.
What is ROM
It is the semiconductor memory whose contents connot be altered, except by destroying the storage unit. Non-erasable memory.
What is RAM
Memory in which each addressable location has a unique addressing mechanism. The time to access a given location is independent of the sequence of prior access.
What is queue
An alternate pipe form of operating system, which handles data in the form of messages rather than bytes; thus a read form a queue returns the next message, which may consist of one or more bytes separated by a boundary. The Operating system is responsible for managing these boundaries.
What is Programmed IO
A form of I/O in which the CPU issues an I/O command to an I/O module and must then wait for the operation to be completed before proceeding.
What is Programmable Logic Array (PLA)
An array of gates whose interconnections can be programmed to perform a specific logic function.
What is a Program
A set of sequenced instructions used to direct and control the operations of the computer in order to solve a problem or to perform a particular task. Also known as a routine.
What is Program Status Word (PSW)
An area in memory used to indicate the order in which instructions are executed, and hold and indicate the status of a computer system. Synonymous with processor status word.
What is Processor
In a computer, a functional unit that interprets and executes instructions. A processor consists of at least an instruction control unit and an arithmetic unit.
What is Process Cycle Time
The time required for shortest well defined CPU micro-operation. It is the basic unit of time for measuring all CPU actions.
What is Process
Process refers to manipulating data and pertains to any action taken by the computer.
What is Process Control
Process control is the automated control of a process, such as a manufacturing process or assembly line.
Saturday, February 22, 2014
What is Printer
An output device used to produce hard copy of computer output that is readable by human beings.
What is Pipeline Processing
Pipeline processing is a category of techniques that provides simultaneous,
What is Piggyback Board
A piggyback board is a small printed circuit board that plugs into another printed circuit board in order to enhance its capabilities. Piggyback boards do not plug into the motherboard, but would plug into the boards that plug into the motherboard.
What is Peripheral
A peripheral is any hardware device connected to a computer, such as monitors, keyboards, printers, plotters, disk and tape drivers, graphics tablets, scanners, joysticks, game paddles and mice.
What is Paging
Paging is the transfer of program segments into and out of memory in a virtual memory environment.
What is Page
In virtual storage system, a fixed length block that has a virtual address and that is transferred as a unit between main memory and auxiliary memory.
What is Page Fault
Occurs when the page containing a referenced word is not in main memory. This causes an interrupt and requires the operating system to bring in the required page.
What is Overhead
Overhead is the amount of processing time taken up by the system software, such as the operating system, teleprocessing monitor or database manager.
What is Output
Output is any computer generated information in printed hard copy, video dispalys or machine readable form, such as disk and tape.
What is Operating System
Software that controls the execution of programs and that provides services such as resource allocation, scheduling, input/output control and data management.
What is Opcode
A code used to represent the operations of a computer. Synonymous with operation code.
What is Online
Online refers to the peripheral device, such as a terminal or printer, that is ready to operate. A personal computer printer can be attached and turned on, yet still not online, if the ONLINE light is out. Pressing the ONLINE button will usually turn it back online.
What is Once's Complement Representation
It is used to represent binary integers. A positive integer is represented as in sign-magnitude. A negative integer is represented by reversing each bit in the representation of a positive integer of the same magnitude.
What is Offline
Offline means not connected to or not mounted in the computer. Even if a terminal, printer or other device is physically connected to the computer, it it still offline if it is not turned on, or not in ready mode. Disks and tapes that have been demounted and stored in the data library are considered offline. Contrast with online, which means connected or mounted and ready to go.
What is Nucleus
That portion of the operating system that contains its basic and most frequently used functions. often, the nucleus remains resident in main memory.
What is Non-volatile memory
It is the memory whose contents are stable and do not require a constant power source.
What is Non-numeric programming
Non-numeric programming deals with objects, such as words, board game pieces and people rather than processor.
What is Multiprogramming
It is a mode of operation that provides for the interleaved execution of two or more computer programs by a single processor.
What is Multiprocessing
Multiprocessing is a simultaneous processing with two or more processors in one computer, or two or more computers that are processing together.
What is Multiplexer
It is a combination of circuit that connects multiple inputs to a single output. At any time, only one of the inputs is selected to be passed to the output.
What is Mini Computer
A minicomputer is a small to medium-scale computer that is the mid-range between a microcomputer and a mainframe. Minicomputers can support from a handful up to several hundred user's terminals.
What is Micro-program
It is a sequence of micro-instructions that are in special storage where they can be dynamically accessed to perform various functions.
What is Micro-programming CPU
It is a CPU whose control unit is implemented using micro-programming.
What is Micro Processor
It is a processor whose elements have been miniaturized into a one or a few integrated circuits.
What is Micro Instruction
It is an instruction that controls data flow and sequencing in a processor at a more fundamental level than machines instructions. Individual machine instructions and perhaps other functions may be implemented by programs.
What is Micro Computer
It is a Computer whose processing unit is a microprocessor. A basic microcomputer includes a microprocessor, storage and an input/output facility, which may or may not be on one chip.
What is Memory
A device or medium that can accept data, hold them, and deliver them on demand at a later time.
What is Memory Mapped I/O
It is a method of addressing I/O modules and external devices. A single address space is used for both main memory and I/O addresses, and the same machine instructions are used for both memory read/write and I/O.
What is Memory Cell
A memory cell is one bit of memory. In dynamic RAM memory, a memory cell is made up of one transistor and one capacitor. In static RAM memory, a memory cell is made up of about five transistors.
What is memory Buffer Register
A register that temporarily holds data read from memory of data to be written into memory.
What is Mask
A Mask is a pattern of bits that is used to accept or reject bit patterns in another set of data. For example, the Boolean AND operation can be used to match a mask of 0s and 1s with a string of data bits. When a 1 occurs in both the mask and the data, the result bit will be contain a 1 in that position.
What is Magnetic tape
A tape with a magnetizable surface layer on which data can be stored by magnetic recording.
What is Magnetic Disk
A flat circular plate with a magnetizable surface layer, on one or both sides of which data can be stored.
What is Macro
It is a set of instructions that takes the form of one statement in an assembler language. The statement provides for several parameters that the programmer files in when coding the program. As the program is compiled, the single macro statement results in the generation of numerous instructions.
What is Macro Instruction
An instruction is a source language that is equivalent to a specified sequence of machine instructions.
What is Machine Language
Machine language is the computer's native language and is the only language the computer understands. In order for a computer to run a program, the program must be in the same machine language of the computer that is executing it, unless the computer is capable of emulating or simulating a foreign machine language.
What is Machine Cycle
A machine cycle is the shortest interval in which an elementary operation can take place within the processor. Machine cycles are made up of some number of clock cycles.
Friday, February 21, 2014
What is Low Level Language (LLL)
A low-level language is a programming language that is very close to machine language. All assembly languages are low-level languages. Contrast with high level language.
What is a Loop
A sequence of instructions that is executed repeatedly until a terminal condition occurs.
What is Logical Error
An error that occurs when the actual logic of a program is different from the desired logic.
What is Local storage
Storage areas, called registers, used by the CPU to interpret instructions and perform arithmetic and logical operations.
What is Load
In computer operations, load is to transfer something into the computers memory on to a peripheral device. To load a program is to copy the program from a disk or tape into memory for execution. To load a disk is to fill it up with programs or data. Load also means to physically mount a storage medium, such as a disk or tape, into or onto the drive.
What is Load Module
A load module is a program in machine language from ready to run in the computer. A load module is the output of a link editor.
Thursday, February 20, 2014
What is linkage editor
A linkage editor is a utility program which adapts a program that has just been assembled or compiled into a particular computer environment. It formally links cross references between separate program modules, and it links the program to various libraries containing pre-written subroutines. The output of a linkage editor is a load module, a program ready to run in the computer.
What is Latch
A latch is an electronic circuit, such as a flip-flop, that maintains one of two states. It is set i.e state 1 and then reset i.e state 1 and then reset i.e state 0.
What is a Laser Printer
A high speed printer that uses a combination of laser-beam and electro-photographic techniques to create printed outputs at speeds in excess of 10 pages per minute and of print quality upto 1200 dots per inch.
What is a Language Processor
A software used to convert source program instructions to object or machine language instructions. Few examples are assembler, compiler and interpreter.
What is Kernel
A kernel is the fundamental part of a program, such as an operating system, that resides in memory at all times.
What is Jump
An instruction or signal which, conditionally or unconditionally, specifies the location of the next instruction and directs the computer to that instruction. A jump is used to alter the normal sequence control of the computer.
What is Job Control Language (JCL)
JCL stands for Job Control Language. JCL is a language that directs the operating system to run application programs in the computer. The JCL states the program size, priority and running sequence, as well as the files and databases used. Originally an IBM term, JCL had become a generic term for a job management language.
Subscribe to:
Posts (Atom)