Claude E Shannon discovered that Boolean algebra can be
used to design& switching circuits.
As computer circuits also use a combination of switches can be one of two
states open or closed. It is also called logic gate.
All operation
within a computer are carried out by means of combination of signal passing
through standard block of built in circuits that are known aslogic gate.
In other words, a logic gate is simply an electronic
circuit which operates on one or more input signals.
These logic gates are the building blocks of all the
circuits is a computer.These are
several typing of gate but we consider haveonly some of the most important ones.
Truth table:- The table
in which all the possible combination of input or output shown is called truth
table.
Type of logic gate:-
AND gate():-
An AND gate is the physical realization of the logical
multiple operation. It is an electronic
circuit that generates an output signal of 1 only if all input signal are also
1.
Or gate (+):-
It is an electronic circuit that generates an output signal
of 1 if any input signal is 1.
Not gate:-
It is an electronic circuit that generates an output signal
which is the reverse of input signal. A NOT gate is also called an inverter it
inverters the input.
NAND Gate:-
NAND Gate is a complement AND gate.That is the output of NAND gate will be a 1
if any one of the input is a o and will be a o only when all the inputs are
one.
NOR GATE:-
A Nor Gate is a complement OR gate. That is the output of a
NOR gate will be a 1 only when all inputs are 0 and will be a 0 if any input
represent.
As we know
that computer understand only two digits that’s is 0 and 1 . hence its name is
digital computer .every computerstore
number ,letters and other special characters , numbers and letters are convert
into binary numbers that’swhy computer
understand it .
“The system
in which, numbers (digits) arrange in a systematic way ,by which we can decide
the value or quantity is known as number system .
Number
system is basically of two types.
1:-Non
positional number system
2:-positional
number system
1:-Non positional number system :-
In early
days , human being counted on fingers . When ten fingers are not adequate,
stones, sticks ,etc were used to indicate values. This method counting uses an
additive approach or non positional number system.
e.g1 for i , II for 2 , III for 3 , IIII for 5,
IIIII for 5.
2positional number system : -
In a positional
number system ,thereare only a few
symbols called digits and thesesymbols
represent different values depending on its position they occupy in the number
the value of each digits in such a number is determined by there consideration
.
1-the digit it self
2-The position of the digit in the number.
3- The base of the number system.
Types of positional number system:
1-Decimal number system
2-Binary number system
3-Octal number system
4-Hexadecimal number system .
1---decimal number
system :-
Most
popular number system which we use in our daily life. This is the number system
,which is made up of ten digits (symbols) . Hence its base is 10. The numbers
are 0, 1,2,3,4,5,6,7,8 and 9
2---binary number
system :-
It is made up of
two digits that are 0 and 1. This number system is exactly like decimal number
system except that the base in 2 instead of 10
3—octal number system –
This is the number
system, which is made up of 8 digits (symbols).
That is
0,1,2,3,4,5,6,7 . Hence its base is 8.
e.g. (3735)8.(43240)8etc.
4—hexadecimal number system –
This is the number system, which is made up of 16 digits
(symbols) .That is 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. hence its base is 16. E.G
(A95B1)16 , (9F2B1)16etc.
A language
is a system of communication. Like natural language English or Hindi, We communicate
one another our ideas and emotions .similarly, a computer language is a means
of communication used to communicate between people and computer.
Types of computer language:-
Computer
language is basically of three types:-
Machine
language.
Assembly
language.
High
level language.
Machine language:-
as we know
that computer know only two digits that is o and 1
(Binary
number).The language which is written with the use of only binary numbers is
known as machine language .inhis language programming is very complex and
confusing .programming in his languageprogrammer should have to deep knowledge
about internal structure of computer.
Assembly language:-
This is
first improved programming language .In this language we can use some codes
(symbols)foradd,subtract,divide multiply etc.
With the
help of assembler, assembly language convert into machine language .it is very
tough
High level language:-
It is very
similar to natural language as English it is also known as problem oriented
language .it is somewhat easy and less confusing .with the help of complierOr
interpreter it convert into machine language.
Compiler:-
Complier
converts high level language to machine language. It translates the whole
program at once.
INTER PRETER :-It is similar to compiler but
difference it that it translate (interpret) the program line by line means it
interpret each statement separately in the program.
ASSEMBLER :-Assembler converts assemble language
to machine language.
Hardware:- Hardware are physical device of a computer which
we can touch and feel . E.g.
keyboard,mouse,printer,harddisk,speaker,motherboard,soundcard etc.
Software:-
As we know
that computer can not do any thing on its own.we give some instruction to the
form of program for accomplish the task.
Software
means a collection a program whose objective is to enhance the capabilities of the hardware.
Relation,betweem,hardware and
software:-
For taking
the desired resuft in the form of computer output, it is important that
hardware and software must work together. A special type of software program
(driver)are used to run the hardware.
Firmware:-A sequence of instruction (software)
that is substituted for hardware and stored in ROM (READ only memory) is known
as firmware.
Types of software:-
Software are
mainly is of two types.
System
software (system package)
Application
software (application package)
System software:-(system package):-
It is a set
of one or more programs, designed to control of a computer system. These
program do not solve any specific problems. .e.g.(operating system)
Application,software,(application
package):-
It is a set
of one or more programs designed to carry out for a specific application. E.g. payroll
package, Tally, CorelDraw.
Booting:-
Booting
means to start the computer. Like television, radio computer not start at
once.at the time of booting computer check all over devices which are attached
into it .it is also check memory etc.
Booting is basically
of two types
Hard
booting (warm booting)To start the computer directly by switch
Soft
booting (cold booting): to restart computer by three key that is Ctrl+Alt+Del keys.
All Computer System Perform the following five operations:-
Inputting, Outputting, Processing, Storing and Controlling.
Input Unit- This is
the unit by which or information entered. Various
Input devices accomplish this task such as keyboard mouse.
Output Unit- It is
responsible for giving the result. Various output devices accomplish this task
such as printer, VDU (visual display unit), Speaker, etc.
Storage Unit- This unit
Provides space for storing and instruction space for intermediate result and
also space for final result.
Central Processing Unit (CPU) - The
control and arithmetic logic unit of a computer system are jointly Known as the
Central Processing Unit.
Arithmetic Logic Unit (ALU) – All
arithmetical (Addition, Subtraction, Multiplication, Division) and logic
(decided) Problem solved in this unit.
Control Unit (CU) - Control
unit controlled all the operation. Such as how does the ALU know what should be
done with the data once they are received, how the final result (not
intermediate result) shall be sent.
The microchip is the heart of computer that actually does the work. It
also Known as the processor or CPU (central processing unit). It is install on
the motherboard inside the computer. There are different types of Processor
available in the market Pentium (P1, P2, P3,
and P4) AMD, Celeron,etc.
As we knows
that any event we remain (store) in our mind.like this computer ,store any
thing in its memory.
It is
basically of to types
1-primary
memory
2-secondory
memory
1-primary memory
Ram (random access memory)
It is volatile
memorymeans ifcomputer turned off ,all data in RAM will belost
(Vanished).
We can random select and use any location of this memory to directly store and
retrieve data and instruction. It is also known as read/ writememorybecause information can be read from a ram chip and can also written
into it.
Rom (read only memory):-
It is nonvolatile
memory means if computer turned off, data will be remain. We can only read the
information from rom .We cannot write in it.
PROM(PROGRAMMABLE READ ONLY MEMORY)
It is like
ROM but manufactures can write one time on this memory
EPROM (ERASABLE PROGRAMMABLE READ
ONLY MEMORY)
Computer manufacturer
can write the program (one or more time) in this memory.
Cache memory:-
It is a
special type of high speed memory which is used to increase the speed of
processing at a rapid rate it is situated between the CPU and main memory (RAM)
.It is also a temporary (volatile) memory.
2 –secondary memory
It is very expensive so the additional memory
is used to increase storage capacity .it is nonvolatile memory. Such as
HARDDISK, FLOPPY, CD ROM DVD PENDRIVE etc.
Memory unit –
The smallest
unit of memory is bit but generally we measure it in byte which is equal 8 bit.
Father Of Computer:
-Charles Babbages ,nineteenth century professor at Cambridgeuniversity, is considered to be the
father of modern digital computer.In computer “Generation” is
used to distinguish between hardware technologies. we discuss the advantages
and disadvantages of various generation.
First Generation (1946 to 1954)
These
generation computer are a ENIAC,EDVAC,EDSAC, etc. These computer made up of
vacuum tubes. These are fragile glass device that could control and amplify
electric signals.
Advantage:-
1. Vacuum
tube was the only electronic components available during those days.
2. Vacuum
tube technology made possible the advent of electronic digital computer.
3. These
computers were the fastest device of their time. They could perform
computations in milliseconds.
Disadvantage :-
1. Too big
in size.
2.Unreliable.
3.Non Portable
4.Thousands of vacuum tubes were used and emitted large amountof heat and burnt out frequently.
5.Air conditioning required.
6.Commercial production was difficult and costly.
ENIAC :-Electronic Numerical Integrator And
Computer.
The transistor, a smaller and more
reliable successor to the VACCUM TUBE was invented in 1947 .How ever computers
that used transistor were not produced until over a decade. The second
Generation emerged with transistor being the brain of the computer.
Advantage:-
1:- Smaller
in size as compared to first generation computer.
2:-More
reliable
3:-Less heat
generated
4:-Better
portability
5:-Wider
commercial use
6:-These
computers were able to reduce computational time from milliseconds 10-3 to microsecond 10-6.
Disadvantage :-
1:-Air
conditioning required.
2:-commercial
production was difficult and costly.
Third Generation (1965-1974)
The third generation was based on IC
technology and the computer that was designed with the use of integrated
circuits was called third generation computers.
Advantage:-
1:-smaller
in size as compared to previous generation computers.
2:-More
reliable than second generation computers.
3:-lower
heat generation.
4:-Easily
portable.
5:-Commercial
production was easier and cheaper.
6:-These
computers were able to reduce computational times from microsecond 10-6to
nanosecond 10-9.
Disadvantage:-
Air
conditioning required in many cases.
Fourth Generation(1975onword):-
Small scale integration(SSI) technology developed in this generation
.It contain only about10 or 20
components later up to 100 of component integrate on a single chip.
This technology came to known as MSI
(medium scale integration)
Then came to
the era to larger scale integration (LSI) WHEN it was possible to integrate
over 30000 components on to a single chip.
Further we
expected that more one million component would be integrate on a single chip
known as very large scale integration (VLSI).
Advantage:-
1:-smaller
in size.
2:-very
reliable.
3:-heat
generated negligible.
4:-No
A.Crequired in most cases.
5:-very fast
6:-maintenance
is minimum required.
(7) Easily
portable due to small size.
(8):-
Cheapest among all generation.
Disadvantage:-
Highly
sophisticated technology required of LSI chips.
Fifth generation(Yet to come):-
Scientist
aim to give us machine with genuine IQ, the ability to reason logically and
with the real knowledge of the world. In nature it will not do only as data
processing but as knowledge processing.Japan has already started work in this
direction few years back.Japan has chosen prolog (programming in logic)
language as its operating software and plans to have the final machine talk
with human being see and deliver picture and hear the normal, natural language.
