Computer overview
I s an automatic, electronic machine
that Computer
o
accept
data & instructions from a user (INPUT)
o
store
the data & instructions (STORAGE)
o
store
&/or output the results to the user (OUTPUT)
TYPE OF COMPUTER
•
Computers
range in size and capability.
•
At
one end of the scale are supercomputers, very large computers with thousands of
linked microprocessors that perform extremely complex calculations.
•
At
the other end are tiny computers embedded in cars, calculators, and appliances.
These computers are built to perform a limited number of tasks.
•
The
personal computer, or PC, is designed to be used by one person at a time. This
section describes the various kinds of personal computers: desktops, laptops,
handheld computers, and Tablet PCs.
Desktop computers
•
Desktop
computers are designed for use at a desk or table.
•
They
are typically larger and more powerful than other types of personal computers.
•
Desktop
computers are made up of separate components.
•
The
main component, called the system unit
•
Other
components are monitor, mouse, and keyboard, connect to the system unit
.
LAPTOP COMPUTER
•
Laptop computers are lightweight mobile PCs with a thin
screen.
•
They
are often called notebook computers because of their small size.
•
Laptops
can operate on batteries, so you can take them anywhere.
•
Unlike
desktops, laptops combine the CPU, screen, and keyboard in a single case.
•
The
screen folds down onto the keyboard when not in use.
LAPTOP
Handheld computers
•
Handheld
computers, also called personal digital assistants (PDAs), are battery-powered
computers small enough to carry almost anywhere.
•
Not
powerful as desktops or laptops
•
These
are useful for scheduling appointments, storing addresses and phone numbers,
and playing games.
•
Some
have more advanced capabilities, such as making telephone calls or accessing
the Internet.
•
Handhelds
have touch screens that you use with your finger or a stylus (a pen-shaped
pointing tool).
Handheld computer
Tablet PCs
•
Tablet
PCs are mobile PCs that combine features of laptops and handhelds.
•
Like
laptops, they're powerful and have a built-in screen.
•
Like
handhelds, they allow you to write notes or draw pictures on the screen,
usually with a tablet pen.
•
They
can also convert your handwriting into typed text.
•
Tablet PC
Basic Parts of
Computer
•
Hardware
–
Mechanical
devices in the computer
–
Anything
that can be touched
•
Software
–
Tell
the computer what to do
–
Also
called a program
–
Thousands
of programs exist
Hardware
•
Hardware
is basically anything that you can touch with your fingers.
§ Computer Case
§ CPU (central processing unit...Pentium chip)
§ Monitor
§ Keyboard & Mouse
§ CD-ROM, DVD,
§ Hard
Drive
§ Memory (RAM)
§ Speakers
§ Printer
Hardware
•
There
are 4 basic types of hardware
§ Input
Devices
§ Output
Devices
§ Storage
Devices
§ Processing
Devices
Input
Devices
•
Input
basically means getting data into the computer to be processed.
•
The
most common input devices are Keyboard and Mouse,
Output
Devices
•
Output
basically means getting data out of the computer.
•
Examples
are
§ Monitor
§ Printer
§ Speakers
Storage Devices
•
Storage
devices are the one used to keep data that has been processed so that data can be
retrieved at a later time to be used again.
•
Examples
are:
hard disc
§ Floppy Disk
§ CD’s, DVD’s
Processing
Device
•
Central
Processing Unit (CPU)
§ The main chip in the computer.
§ It is the heart of the computer and
communicates with the output, input and storage devices to perform tasks that
are important to the functioning of the computer.
CPU
•
Its
main function is
§ to process instructions
§ manage the flow of information
through the computer system.
§ perform calculations.
•
CPU
composed of two main components:
•
Control
Unit
•
Arithmetic
and Logic Unit (ALU)
Control Unit
•
Tells
the rest of the Computer system how to carry out a program’s instructions.
•
It
direct the movement of electronic signals between memory and ALU
•
It
also direct these control signals between the CPU and output device
Arithmetic
and Logic Unit
This performs two types of operation,
arithmetic and logical
§ Arithmetic Operations: Are
fundamental math operations; addition, subtraction, multiplication and
division.
§ Logical Operations: Consists of
comparisons. That two pieces of data or more are compared to see whether one is
equal to (=), less than (<), or greater than (>) the other, etc
ABACUS
4th Century B.C.
The
abacus, a simple counting aid, may have been invented in Babylonia (now Iraq)
in the fourth century B.C.
This
device allows users to make computations using a system of sliding beads arranged on a
rack.
BLAISE
PASCAL
(1623 - 1662)
(1623 - 1662)
In
1642, the French mathematician and philosopher Blaise Pascal invented a
calculating device that would come to be called the "Adding Machine".
Originally
called a "numerical wheel calculator" or the "Pascaline",
Pascal's invention utilized a train of 8 moveable dials or cogs to add sums of
up to 8 figures long. As one dial turned 10 notches - or a complete revolution
- it mechanically turned the next dial.
Pascal's
mechanical Adding Machine automated the process of calculation. Although slow
by modern standards, this machine did provide a fair degree of accuracy
and speed.
CHARLES
BABBAGE
(1791 - 1871)
(1791 - 1871)
Charles
Babbage was an English mathematician and professor.
In 1822, he persuaded the British government
to finance his design to build a machine (called difference engine and later
analytical engine) that would calculate tables for logarithms.
With
Charles Babbage's creation of the "Analytical Engine", (1833)
computers took the form of a general purpose machine.
Charles
Babbage is called father of computer
Aiken
thought he could create a modern and functioning model of Babbage's Analytical
Engine.
He
succeeded in securing a grant of 1 million dollars for his proposed Automatic
Sequence Calculator; the Mark I for short. From IBM.
In
1944, the Mark I was "switched" on. Aiken's colossal machine spanned
51 feet in length and 8 feet in height. 500 meters of wiring were required to
connect each component.
HOWARD
AIKEN (1900 - 1973)
The
Mark I did transform Babbage's dream into reality and did succeed
in putting IBM's name on the forefront of the burgeoning computer industry.
From 1944 on, modern computers would forever be associated with digital
intelligence
ENIAC 1946
Electronic
Numerical Integrator And Computer
Under
the leadership of J. Presper Eckert (1919 - 1995) and John W. Mauchly
(1907 - 1980) the team produced a machine that computed at speeds 1,000 times
faster than the Mark I was capable of only 2 years earlier.
Using
18,00-19,000 vacuum tubes, 70,000 resistors and 5 million soldered joints. This
massive instrument required the output of a small power station to operate it.
ENIAC
1946
It
could do nuclear physics calculations (in two hours) which it would have taken
100 engineers a year to do by hand.
The
system's program could be changed by rewiring a panel.
TRANSISTOR1948
In
the laboratories of Bell Telephone, John Bardeen, Walter Brattain and William
Shockley discovered the "transfer resistor"; later labelled the
transistor.
Advantages:
increased
reliability
1/13
size of vacuum tubes
consumed
1/20 of the electricity of vacuum tubes
were
a fraction of the cost
TRANSISTOR
1948
ALTAIR
1975
The
invention of the transistor made computers smaller, cheaper and more reliable.
Therefore, the stage was set for the entrance of the computer into the domestic
realm. In 1975, the age of personal computers commenced.
Under
the leadership of Ed Roberts the Micro Instrumentation and Telemetry
Company (MITS) wanted to design a computer 'kit' for the home hobbyist.
Based
on the Intel 8080 processor, capable of controlling 64 kilobyes of memory, the
MITS Altair - as the invention was later called - was debuted on the cover of
the January edition of Popular Electronics magazine.
Presenting
the Altair as an unassembled kit kept costs to a minimum. Therefore, the
company was able to offer this model for only $395. Supply could not keep up
with demand.
ALTAIR
FACTS:
No
Keyboard
No
Video Display
No
Storage Device
IBM
(PC) 1981
On
August 12, 1981 IBM announced its own personal computer.
Using
the 16 bit Intel 8088 microprocessor, allowed for increased speed and huge
amounts of memory.
Unlike
the Altair that was sold as unassembled computer kits, IBM sold its
"ready-made" machine through retailers and by qualified salespeople.
To
satisfy consumer appetites and to increase usability, IBM gave prototype IBM
PCs to a number of major software companies.
For
the first time, small companies and individuals who never would have imagined
owning a "personal" computer were now opened to the computer world.
MACINTOSH
(1984)
IBM's
major competitor was a company lead by Steve Wozniak and Steve Jobs;
the Apple Computer Inc.
The
"Lisa" was the result of their competitive thrust.
This
system differed from its predecessors in its use of a "mouse" - then
a quite foreign computer instrument - in lieu of manually typing commands.
However,
the outrageous price of the Lisa kept it out of reach for many computer buyers.
Apple's
brainchild was the Macintosh. Like the Lisa, the Macintosh too would make use
of a graphical user interface.
Introduced
in January 1984 it was an immediate success.
The
GUI (Graphical User Interface) made the system easy to use.
The
Apple Macintosh debuts in 1984. It features a simple, graphical interface, uses
the 8-MHz, 32-bit Motorola 68000 CPU, and has a built-in 9-inch B/W screen.
Computer
Generations
FIRST
GENERATION
(1945-1956)
(1945-1956)
First
generation computers were characterized by the fact that operating instructions
were made-to-order for the specific task for which the computer was to be used.
Each
computer had a different binary-coded program called a machine language that
told it how to operate.
This
made the computer difficult to program and limited its versatility and speed.
Other
distinctive features of first generation computers were the use of vacuum tubes
for circuitry (responsible for their breathtaking size) and magnetic drums for
data storage.
Problems:
Vacuum
tube generated a great deal of heat
Tubes
burnt out frequently
Thus,
first generation computers were Huge, Slow, Expensive, Unreliable
The ENIAC and UNIVAC are first generation
computing devices
CHARACTERISTICS
First
generation computers were based on vacuum tubes.
The
operating systems of the first generation computers were very slow.
They
were very large in size.
Production
of the heat was in large amount in first generation computers
Machine language was used for programming.
First
generation computers were unreliable.
They
were difficult to program and use.
UNIVAC, EDVAC, EDSAC and ENIAC computers
are examples of first generation computing devices.
SECOND
GENERATION
(1956-1963)
(1956-1963)
These
second generation computers were also of solid state design, and contained
transistors in place of vacuum tubes
Transistors
Were
smaller than vacuum tubes
They
needed no warm up time
Consumes
less energy
Generate
much less heat
Faster
and more reliable
These
computers were smaller, faster and cheaper
They
also contained all the components we associate with the modern day computer:
printers, tape storage, disk storage, memory, operating systems, and stored
programs.
One
important example was the IBM 1401
CHARACTERISTICS
Transistors were
used in place of vacuum tubes.
Second
generation computers were smaller in comparison with the first generation
computers.
They
were faster in comparison with the first generation computers.
They
generated less heat and were less prone to failure.
They
took comparatively less computational time
Assembly
language was used for programming.
Second
generation computers has faster input/output devices.
IBM
7000, NCR 304, IBM 650, IBM 1401, ATLAS and Mark III are the examples
of second generation computers.
THIRD
GENERATION
(1956-1963)
(1956-1963)
Though
transistors were clearly an improvement over the vacuum tube, they still
generated a great deal of heat, which damaged the computer's sensitive internal
parts.
The
development of integrated circuit (IC) signal the beginning of the third
generation computers
Integrated
circuit (IC) is a collection of
transistors and electrical circuits all in a single crystal called
microchip
The
microchip is a complete electronic circuit on a small chip silicon knows as a
semi-conductor
Integrated
circuit technology reduced the size and cost of computers
Today’s
integrated circuits are no more than a centimeter long, and they can carry
millions of microscopic transistors
As a
result, computers became ever smaller as more components were squeezed onto the
chip.
Another
third-generation development included the use of an operating system that
allowed machines to run many different programs at once with a central program
that monitored and coordinated the computer's memory.
Advantages
of integrated circuits:
Silicon
chips were reliable, compact and cheaper
Sold
hardware and software separately which created the software industry
Customer
service industry grew
General
characteristics of this computer generation
IC
was used instead of transistors in the third
generation computers.
Third
generation computers were smaller in size and cheaper as compare to
the second generation computers.
They were fast and more reliable.
High
level language was developed.
Magnetic
core and solid states as main storage.
They were able to reduce
computational time and had low maintenance cost.
Input/Output
devices became more sophisticated.
PDP-8,
PDP-11, ICL 2900, IBM 360 and IBM 370 are the examples of third
generation computers.
FOURTH
GENERATION (1971-Present)
The
microprocessor brought the fourth generation of computers as thousands of
integrated circuits were built onto a single silicon chip
The
microprocessor is a large scale integrated circuit on a tiny silicon chip that
contains thousands or millions of transistors in in multiple ICs.
A
microprocessor containing about 100 components is called LSI (Large Scale
Integration) and the one, which has more than 1000 such components, is called
as VLSI (Very Large Scale Integration).
CHARACTERISTICS
The
fourth generation computers have microprocessor-based systems
They
are the cheapest among all the computer generation.
The
speed, accuracy and reliability of the computers were improved in fourth
generation computers.
Many
high-level languages were developed in the fourth generation such as COBOL,
FORTRAN, BASIC, PASCAL and C language.
A
further refinement of input/output devices was developed.
Networking
between the systems was developed
IBM
4341, DEC 10, STAR 1000, PUP 11 and APPLE II are the examples of fourth
generation computers
FIFTH
GENERATION (present & beyond)
Fifth
generation computing devices are based on artificial intelligence and they are
still in development
Computers
today have some attributes of fifth generation computers and applications such
as voice recognition are being used today
The
use of parallel processing and superconductors is helping to make artificial
intelligence a reality.
Quantum
computation and molecular and nanotechnology will radically change the face of
computers in years to come.
The
goal of fifth-generation computing is to develop devices that respond to
natural language input and are capable of learning and self-organization.
5th
generation computers use ULSI (Ultra-Large Scale Integration) chips. Millions
of transistors are placed in a single IC in ULSI chips
CHARACTERISTICS
The fifth generation computers will
use super large scale integrated chips
They will have artificial intelligence.
They
will be able to recognize image and graphs.
Fifth
generation computer aims to be able to solve highly complex problem
including decision making, logical reasoning.
They
will be able to use more than one CPU for faster processing speed.
Fifth
generation computers are intended to work with natural language.
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