COMPUTER is an advanced
electronic device that takes raw data as input from the user and processes
these data under the control of set of instructions (called program) and gives
the result (output) and saves output for the future use.
We can use a computer to type documents, send
email, and browse the internet.
The word "computer" was first recorded
as being used in 1613 in a book called “The young mans gleanings” by English
writer Richard Braithwait I haue read the truest computer of Times, and the
best Arithmetician that euer breathed, and he reduceth thy dayes into a short
number. and was originally was used to describe a human who performed
calculations or computations. The definition of a computer remained the same
until the end of the 19th century when people began to realize machines never
get tired and can perform calculations much faster and more accurately than any
team of human computers ever could.
Functionalities of a computer::
Any digital computer carries out five functions in
gross terms:
Ø Takes
data as input.
Ø Stores
the data/instructions in its memory and can use them when required.
Ø Processes
the data and converts it into useful information.
Ø Outputs
the information.
Ø Controls
all the above four steps.
Advantages::
HIGH SPEED
Ø Computer
is a very fast device.
Ø It
is capable of performing addition of very big data.
Ø The
computer has units of speed in microsecond, nanosecond and even the picosecond.
Ø It
can perform millions of calculations in a few seconds as compared to man, who
can spend many months for doing the same task.
ACCURACY
Ø In
addition to being very fast, computers are very accurate.
Ø The
computer has performed calculations 100% error-free.
Ø Computers
perform all jobs with 100% accuracy.
STORAGE CAPABILITY
Ø The
computer has much more storage capacity than human beings.
Ø It
can store large amount of data.
Ø It
can store any type of data such as images, videos, text, audio and any other
type.
DILIGENCE
Ø Unlike
human beings, a computer is free from monotony, tiredness and lack of
concentration.
Ø It
can work continuously without creating any error and boredom.
Ø It
can do repeated work with same speed and accuracy.
VERSATILITY
Ø A
computer is a very versatile machine.
Ø A
computer is very flexible in performing the jobs to be done.
Ø This
machine can be used to solve the problems relating to various different fields.
Ø At
one instant, it may be solving a complex scientific problem and the very next
moment it may be playing a card game.
RELIABILITY
Ø A
computer is a reliable machine.
Ø Modern
electronic components have failure-free long lives.
Ø Computers
are designed to make maintenance easy.
AUTOMATION
Ø Computer
is an automatic machine.
Ø Automation
means ability to perform the task automatically.
Ø Once
a program is given to computer, i.e., stored in computer memory, the program
and instructions can control the program execution without human interaction.
REDUCTION IN PAPER WORK
Ø The
use of computers for data processing in an organization leads to reduction in
paper work and speeds up the process.
Ø As
data in electronic files can be retrieved as and when required, the problem of
maintenance of large number of files gets reduced.
REDUCTION IN COST
Ø Though
the initial investment for installing a computer is high but it substantially
reduces the cost of each of its transaction.
Computer - CPU
Ø CPU
is considered as the brain of the computer.
Ø CPU
performs all types of data processing operations.
Ø It
stores data, intermediate result and instructions (program).
Ø It
controls the operations of all parts of computer.
CPU itself has the following three components.
Ø Memory
or Storage Unit
Ø Control
Unit
Ø ALU
(Arithmetic Logic Unit)
Memory Or Storage Unit:
This unit can store instructions, data and intermediate
results. This unit supplies information to the other units of the computer when
needed. It is also known as internal storage unit or main memory or primary
storage or Random access memory[RAM).
Its size affects speed, power and capability. There
are primary memory and secondary memory, two types of memories in the computer.
Functions of Memory Unit are:
Ø It stores all the data to be processed and the
instructions required for processing.
Ø It stores intermediate results of processing.
Ø It stores final results of processing before
these results are released to an output device.Ø All inputs and outputs are
transmitted through main memory.
Control Unit:
This unit controls the operations of all parts of
computer. It does not carry out any actual data processing operations.
Functions of this unit are:
Ø It is responsible for controlling the transfer
of data and instructions among other units of a computer.
Ø It manages and coordinates all the units of the
computer.
Ø It obtains the instructions from the memory,
interprets them and directs the operation of the computer.
Ø It communicates with Input/Output devices for
transfer of data or results from storage.
Ø It does not process or store data.
ALU (Arithmetic Logic Unit):
This unit consists of two subsections namely:
Ø Arithmetic Section
Ø Logic Section
Arithmetic Section:
Function of Arithmetic section is to perform
arithmetic operations like addition, subtraction, multiplication and division.
All complex operations are done by making repetitive use of above operations.
Logic Section:
Function of logic section is to perform logic
operations such as comparing, selecting, matching and merging of data.
Types of CPUs
There are two different types of CPUs. There is a
32-bit CPU and there is a 64-bit CPU. The main difference between these two
processors is the structure. The older processor which is the 32-bit processor
has a structure that can process instructions less efficiently than a 64-bit
Processor can.
Also, a 32-bit processor can handle less
instruction at one time than a 64-bit processor can. The more bits, the more
that processor can handle and, since 64-bits is larger than 32-bits, that means
that a 64-bit processor is the better choice as it can handle more instructions
in one load. Moreover, a 32-bit processor can only handle 4GB of memory,
compared to a 64-bit processor which can handle up to 16EB (=1 billion GB) of
memory or RAM. Now, the amount of memory that a processor can handle does not
only depend on the processor, but it also depends on the Operating System of
the machine.
Multi-core processor
 |
Generic dual-core processor, with CPU-local level 1 caches, and a shared, on-die level 2 cache
A multi-core processor is a single computing
component with two or more independent actual central processing units (called
"cores"), which are the units that read and execute program
instructions. The instructions are ordinary CPU instructions such as add, move
data, and branch, but the multiple cores can run multiple instructions at the
same time, increasing overall speed for programs amenable to parallel
computing. Manufacturers typically integrate the cores onto a single integrated
circuit die (known as a chip multiprocessor or CMP), or onto multiple dies in a
single chip package.
Processors were originally developed with only one
core. A dual-core processor has two cores (e.g. AMD Phenom II X2, Intel Core
Duo), a quad-core processor contains four cores (e.g. AMD Phenom II X4, Intel's
quad-core processors, see i5, and i7 at Intel Core), a 6-core processor
contains six cores (e.g. AMD Phenom II X6, Intel Core i7 Extreme Edition 980X),
an 8-core processor contains eight cores (e.g. Intel Xeon E7-2820, AMD
FX-8350), a 10-core processor contains ten cores (e.g. Intel Xeon E7-2850), a
12-core processor contains twelve cores. A multi-core processor implements
multiprocessing in a single physical package.
 |
| An AMD Athlon X2 6400+ dual-core processor |
 |
| An Intel Core 2 Duo E6750 dual-core processor |
Computer Memory
Drum memory, an early form of
computer memory that actualy did use a drum as a working part with data loaded
to the drum. The drum was a metal cylinder coated with recordable ferromagnetic
material. The drum also had a row of read-write heads that wrote and then read
the recorded data.
Magnetic core memory
(ferrite-core memory) is another early form of computer memory. Magnetic
ceramic rings called cores, stored information using the polarity of a magnetic
field.Semiconductor memory is computer memory we are all familiar with, computer memory on a intergrated circuit or chip. Referered to as random-access memory or RAM, it allowed data to be accessed randomly, not just in the sequence it was recorded.
Timeline of Computer Memory
1834
Charles
Babbage
begins build his "Analytical Engine", precursor to the computer. It
uses read-only memory in the form of punch
cards.
1932
Gustav
Tauschek invents drum memory in Austria.
1936
Konrad
Zuse
applies for a patent for his mechanical memory to be used in his computer. This
computer memory is based on sliding metal parts.
1939
Helmut
Schreyer invents a prototype memory using neon lamps.
1942
The Atanasoff-Berry
Computer
has 60 50-bit words of memory in the form of capacitors mounted on two
revolving drums. For secondary memory it uses punch cards.
1947
Frederick
Viehe of Los Angeles, applies for a patent for an invention that uses magnetic
core memory. Magnetic drum memory is independently invented by several people.
- An Wang
An Wang invented the magnetic pulse controlling device, the principle upon which magnetic core memory is based. - Kenneth Olsen
Kenneth Olsen invented vital computer components, best known for "Magnetic Core Memory" Patent No. 3,161,861 and as being the cofounder of Digital Equipment Corporation. - Jay Forrester
Jay Forrester was a pioneer in early digital computer development and invented random-access, coincident-current magnetic storage.
1949
Jay
Forrester
conceives the idea of magnetic core memory as it is to become commonly used,
with a grid of wires used to address the cores. The first practical form
manifests in 1952-53 and renders obsolete previous types of computer memory.
1950
Ferranti
Ltd. completes the first commercial computer with 256 40-bit words of main
memory and 16K words of drum memory. Only eight were sold.
1951
Jay
Forrester
files a patent for matrix core memory.
1952
The
EDVAC computer is completed with 1024 44-bit words of ultrasonic memory. A core
memory module is added to the ENIAC computer.
1955
An
Wang
was issued U.S. patent #2,708,722 with 34 claims for magnetic memory core.
1966
Hewlett-Packard
releases their HP2116A real-time computer with 8K of memory. The newly formed
Intel starts sell a semiconductor chip with 2,000 bits of memory.
1968
USPTO grants patent 3,387,286 to IBM's Robert
Dennard
for a one-transistor DRAM cell. DRAM stands for Dynamic RAM (Random Access
Memory) or Dynamic Random Access Memory. DRAM will become the standard memory
chip for personal computers replacing magnetic core memory.
1969
Intel
begin as chip designers and produce a 1 KB RAM chip, the largest memory chip
todate. Intel soon switch to being notable designers of computer
microprocessors.
1970
Intel
releases the 1103
chip,
the first generally available DRAM memory chip.
1971
Intel
releases the 1101 chip, a 256-bit programmable memory, and the 1701 chip, a
256-byte erasable read-only memory (EROM).
1974
Intel
receives a U.S. patent for a "memory system for a multichip digital
computer".
1975
Personal
consumer computer Altair released, it uses Intel's 8-bit
8080 processor and includes 1 KB of memory. Later in the same year, Bob Marsh
manufacturers the first Processor Technology's 4 kB memory boards for the
Altair.
1984
Apple
Computers
releases the Macintosh personal compututer. It is the first computer that came
with 128KB of memory. The one-megabyte memory chip is developed.
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