Fundamentals of computer organization(gtu mca ppt) by nagaria.keval


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                  Fundamentals of Computer Organization

The name of the CPU registers in a single address instruction format. The accumulator, or
AC, is implicitly stores one of the two operands for the instruction.

An address is the number of a particular memory or peripheral storage location. Every
word of a memory and every sector on a disk have their own unique address.

Address Bus:
The portion of a system bus used to transfer address. Typically the address identifies a
main memory location or an I/O device.

Address Mode:
The address mode is how a machine instruction refers to memory and peripheral devices.

Address Register:
A register in a processing unit, that contains the address of the storage location being

A general term referring to the structure of all or part of a computer system. The term also
covers the design of system software such as the operating system as well as referring to
the combination of hardware and basic software that links the machines on a computer

Arithmetic and Logic Unit (ALU):
A part of a CPU that performs arithmetic operation, logic operations and related operations

Associative Memory:
A memory whose storage location are identified by their contents, or by a part of their
contents, rather than by their names or positions.

In numeric system, the base also called the radix, is the number the number that
determines the value of each digit position. For example, in a base 10 (decimal) system,
each position worth 10 times the value of the position just next to its right.

Base Address:
A numeric value that is used as a reference in the calculation of addresses in the execution
of a computer program

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                   Fundamentals of Computer Organization

BCD (binary coded decimal) code:
One of the early coding system used by computers which is based on the idea of converting
each digit of a decimal number into its binary equivalent rather than converting the
converting the entire decimal value into a pure binary form.

Binary number system:
A number system with a base of two. It consists of two digits, namely 0 and 1.

In the pure binary numeration system, either of the digits 0 and 1.

Boolean Expression:
A Boolean expression is a statement using Boolean operators that expresses a condition
which is either true or false.

Boolean Function:
A mathematical function in Boolean algebra for example, w=x+y.z

Boolean Operator:
A Boolean Operator is one of the Boolean logic operators such as AND, OR, NOT, etc.

Storage used to compensate for a difference in rate of flow of data, or time of occurrence of
events, when transferring data from one device to another.

An error in a computer program.

A shared communication path consisting of one or more connection lines. In some
computer system, CPU, memory and I/O devices are connected by a common bus. Since the
lines are shared by all components, only one component at a time can successfully transmit.

Equivalent to 8 bits. Also referred to as an octet.

Cache Memory:
Special buffer storage, smaller and faster than main storage, that is used to hold a copy of
instructions and data that are likely to be needed next by the processor, and that have been
obtained automatically from main storage.

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                   Fundamentals of Computer Organization

Compact disk read only memory. A non erasable disk used for storing computer data. The
standard system uses 12cm disks and can hold more than 550MB.

That portion of a computer that fetches and executes instruction. It consists of an
arithmetic and logic unit (ALU), a control unit, and register. Often simply referred to as

Clock Pulse:
A clock pulse is signal that is used to synchronize the operation of an electronic system.
Clock pulses are continuous, precisely spaced changes in voltage.

Clock Rate:
Inverse of clock cycle time, usually measured in MHz

Combinational Circuit:
A logic device whose output values, at any given instant, depends only upon that input
values at that time. A combinational circuit is a special case of sequential circuit that does
not have a storage capability Synonymous with machine instruction.

Compact Disk:
A non erasable disk used for storing digitized audio information, using laser optical

A computer is a general purpose machine that processes data according to a set of
instructions that are fed into it.

Computer Instruction:
An instruction that can be recognized by the processing unit of the computer for which it is
designed. Synonymous with machine instruction.

Computer Instruction Set:
A complete set of the operations of the instruction of a computer together with a
description of the types of meanings that can be attributed to their operands. Synonymous
with machine instruction set

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                   Fundamentals of Computer Organization

Computer System:
The various components (input and output devices, storage, CPU) of a computer integrated
together to perform the steps called for in the program being executed.

Control Bus:
That portion of a system bus used for the transfer of control.

Control Registers:
CPU registers employed to control CPU operation. Most of these register are not user-

Control Storage:
A portion of storage that contains micro program/microcode. Synonymous with control

Control Unit:
That part of the CPU that controls CPU operations, including ALU operations, the
movement of data within CPU, and the exchange of data and control signals across external
interfaces (Eg. System Bus)

A device, register or storage location for storing integers that are suitably incremented or
decremented to represent the number of occurrences of an event.

Raw facts and figures, such as order and payments, which are processed into information
such as balance due and quality on hand.

Data Bus:
That portion of a system bus used for the transfer of data.

A device that has a number of input lines of which any number may carry signals and a
number of output lines of which not more than one may carry signal, there being a one-to-
one correspondence between the outputs and the combination of input signals.

A digit is a single character in a numbering system. In the decimal system, the digits are 0
though 9. In the binary system the digits are 0 and 1.

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                   Fundamentals of Computer Organization

Digital Computer:
Digital computer is a computer that accepts and process data that has been converted into
discrete binary number. Almost all computer are digital.

Direct Access:
The capability to obtain data from a storage device or to enter data into a storage devices in
a sequence independent of their relative position, by means of addressed that indicate the
physical location of the data.

Direct Address:
As address that designates the storage location of an item of data to be treated as operand.
Synonymous with one level address.

Direct Memory Access:
A form of I/O in which a special module, called a DMA module, Controls the exchange of
data between main memory and an I/O module.

Dynamic RAM:
A RAM whose cells are implemented using capacitors a dynamic RAM will gradually lose its
data unless it is periodically refreshed.

Error Correcting Code:
A code in which each character or signal conforms to specific rules of construction so that
deviations from these rules indicate the presence of an error and in which some or all of
the detected error can be connected automatically.

Error Detecting Code:
A code in which each character or signal conforms to specific rules of construction so that
deviations from these rules indicate the presence of an error.

A circuit or device containing active elements, capable of assuming either one of two stable
states at a given time. Synonymous with bistable circuit or toggle.

An electronic circuit that produce an output signal that is simple Boolean operation on its
inputs signals

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Hamming Code:
In data communication, hamming code is an error detection code that is interspersed with
the bits of end character. At the receiving station, the code is checked in ordered to detect
missing bits, and one-bit errors cab be corrected automatically.

Handshaking are the signals transmitted back and forth over a communications network
that establish a valid connection between two parties. Handshaking is part of the
communications protocol that dictates the codes and electronic signaling required.

Hard disk:
Hard disk is a magnetic disk made of metal and covered with a magnetic recording surface.

I/O Processor:
An I/O module, with its own processor and capable of executing its own specialized I/O
instruction or in some cases, general purpose machine instructions

Input – Output (I/O):
Pertaining to either input or output, or boot refers to the movement of data between a
computer and a directly attached peripheral.

Logic Circuit:
A logic circuit is a circuit that performs logic functions.

Logic gate:
A logic gate is a collection of transistor and other electronic components that make up a
Boolean logical operation, such as AND, NAND, OR and NOR transistor make up logic gates.
Logic gates make up circuits. Circuits make up electronic systems.

Logical Error:
An error that occurs when the actual logic of a program is different from the desired logic

Magnetic Disk:
A flat circular plate with a magnetizable surface layer, on one or both sides of which data
can be stored.

Magnetic Type:
A tape with magnetizable surface layer on which data can be stored by magnetic recording.

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                  Fundamentals of Computer Organization

Main Memory:
Program-addressable storage from which instruction and data can be loaded directly into
registers for subsequent execution or processing

A device or medium that can accept data, hold them and deliver them on demand at a later

Memory Buffer Register:
A register that temporarily holds data read from memory or data to be written into

Memory-Mapped I/O:
A method of addressing I/O modules and external devices a signal 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.

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

A combinational circuit that connects multiple inputs to a signal output. At any time, only
one of the inputs is selected to be passed to the output.

Nonvolatile Memory:
Memory whose contents are stable and do not require a constant power source.

Random Access Memory:
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.

Read Only Memory:
Semiconductor memory whose contents cannot be altered, except by destroying the
storage unit. Nonerasable memory

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