introduction and brief history of computers
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Introduction & History of Computers, Their
Applications
By: Khalid Khan
Sarhad University of Science & Information Technology Peshawar
Contents• What is Computer?• Who is a User?• Data & Information• Information Technology (IT)• History of Computers
• Generations• Types of Computers• Classification of Computers
What is Computer
What is Computer?Definitions:• A computer is normally considered as
calculating machine that can perform arithmetic operation at a very high speed.
• Computers are electronic devices that is programmed to • accept data (input), • (process) that data into useful information, • produce (output), and then • (store) for later use.
Who is a user?• Someone that communicates with a
computer
Data & InformationDefinitions:• DATA A collection of raw facts and figures is called data. It may consist of numbers, characters, symbols
etc
• INFORMATION Processed data is called information. It is more meaningful than data.
Information Technology• Information is data that is organized,
meaningful, and useful.• Information technology is the use of
systems (especially computers and telecommunications) for storing, retrieving, and sending information..
• Computer is a very important component of information technology
History of Computers
Mechanical computers
(1600-1900)early designs for
more traditional computers - based on mechanical techniques.
Slide rule
Abacus
Pascal Calculator
Electronic computers(1937-1953)
First Generation - Vacuum Tubes
1. From 1946 to 1956 •It can perform 2,000 to 16,000 additions per second •Had main memory 100 bytes to 2 kilobytes
2. Used vacuum tubes 3. Very large machines
•special rooms to house them with air conditioning •specially trained technicians to run & maintain
Second Generation - Transistors
1.From 1959 to around 1965 2.Smaller, faster, and more reliable
used transistors 6,000 to 3,00,000 operations/s main memory 6 kilobytes to 1.3
megabytes3.one-tenth the price of a 1st
Generation4.become common in larger
businesses and universities
Third Generation - Integrated Circuits
1. Form 1965 to around 1972 2. Used integrated circuits – many
transistors on one piece of silicon 3. Smaller, faster, more reliable, and
lower in price • Size of a stove or refrigerator, some can fit
on desktops • Can do 100,000 to 400,000,000 operations
per second • Cost about one-tenth the amount of second
generation computers 4. These Computers become very
common in medium to large businesses
Fourth Generation - Microprocessors1. From 1972 until now 2. Used large scale to very large scale integrated
circuits • Put more than one IC on a silicon chip • Can do more than one function
3. smaller, faster, more reliable, and lower in price • Size of a television or much smaller • Can do 500,000 to 1,000,000,000
operations/second • Cost one-tenth, or less, the amount of third
generation 4. very common in homes and business
Types of Computer
• Analog computers
• Digital computers
Analog Computers• An analog computer recognizes data as a
continuous measurement of a physical property.
• It has no state• Its output is usually displayed on a meter
or graphs.• Examples are Analog clock, speedo-meter
of a car, thermo-meter etc
Digital Computers• It works with numbers• They breaks all types of information into tiny
units and use numbers to represent those pieces of information.
• Everything is described in two states i.e. either ON (1) or OFF (0).
• They are very fast and have big memory
Classification of Computers
Basic Map
Micro Computers
Mainframe Computers
Super Computers
Mini Computers
Digital Computers
Desktop Computers
Laptop Computers
Handheld Computers
Workstations Computers
Servers Computers
Supercomputer• A supercomputer is a computer with a high-level
computational capacity compared to a general-purpose computer.
• It comprised of multiple high performance computers working in parallel as a single system.
• Super Computers uses thousands of processor at a same time.
• Used for nuclear weapon weather forecasting, Scientific Simulition, oil and gas exploration or in large companies.
Mainframe• Mainframes are huge
computers that could fill an entire room or even a whole floor!
• mainframes can run multiple instances of operating systems at the same time.
• Mainframe are used primarily by large organizations for critical applications, bulk data processing
• It uses for online data storage.• Mainframe used for
transaction processing in banking, Airlines etc
Workstation• A desktop computer that has a more powerful
processor,
• additional memory (RAM, Hard drive) and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development.
• Multiple users can use single workstation all together.
Server• A computer that has been optimized to provide
services to other computers over a network.
• Servers usually have powerful processors, lots of memory and large hard drives.
• Multiple CPU’s & Hard drives
DESKTOP
• A PC that is not designed for portability.
• you will set the computer up in a permanent location.
• Most desktops offer more power, storage and versatility for less cost than portable computers.
Laptop
• Also called notebooks.
• Laptop are portable computers that integrate the display, keyboard, a pointing device or trackball, processor, memory and hard drive all in a battery-operated package.
Palmtop• More commonly known as Personal
Digital Assistants (PDAs) • palmtops are tightly integrated
computers that often use flash memory instead of a hard drive for storage.
• usually do not have keyboards but rely on touchscreen technology for user input.
• A slightly larger and heavier version of the palmtop is the handheld computer.
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