To start I would like to quote some predictions of the influential people in the past about computers which shows how much computers have revolutionized the world.
I think there is a world market for maybe five computers.
– Thomas Watson, chairman of IBM, 1943
Computers in the future may weigh no more than 1.5 tons.
– Popular Mechanics, 1949
There is no reason anyone would want a computer in their home.
–Ken Olson, CEO, Digital Equipment Corp., 1977
Let’s look at what is a computer and the history and evolution of computers!
- A computer is a machine that
– inputs (takes in) facts and information (known as data*)
– then processes (does something to or with) it
– can also store data
– afterwards it outputs, or displays, the results for you to see
* Data is all kinds of information, including, pictures, letters, numbers, and sounds
- The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed
– a list of instructions (the program) can be given to the computer e.g.,
– add one number to another
– move some data from one location to another
– send a message to some external device, etc
– it will store them (in memory)
– and carry them out (execute) some time in future
– Usually in the same order in which the instructions were given
- The first use of the word “computer” was recorded in 1613
– referring to a person who carried out calculations, or computations !
– The word continued to be used in that sense until the middle of the 20th century
- before modern electronic computers were developed
- The history of computers begins with two separate technologies
– Automated Calculation
- Computer in the history were mechanical calculating devices such as
– Abacus, 3000 B.C
– Slide rule
Chinese Abacus: for performing arithmetic processes
Slide Rule: for performing multiplication, division, computing roots, logarithms, trigonometric functions
- ENIAC - Electronic Numerical Integrator And Computer - was the first general-purpose electronic computer developed around 1946
- operated at 5 kIPS [thousand instructions per second]
- weighed 30 tons
- size was roughly 8.5 x 3 x 80 feet
- contained around 5 million hand-soldered joints
- consumed 150 kW of power; enough to dim the lights of Philadelphia when it was run!
- Input was given from an IBM card reader
- An IBM card punch was used for output
– Today’s desktops can perform 10000+ MIPS
Working on, rather, ‘inside’ ENIAC.
IBM Punch Card: Programs and data were punched by hand or a key-punch-machine and read into a card reader.
A brief description about the types of modern computers with whom most of you would be familiar:
– These are the most widely used and the fastest-growing type of computers. There are two major categories:
- Desktop Computers are small enough to fit on top or along the side of a desk and yet are too big to carry around.
- Personal Computers
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2. Portable Computers are small enough and light enough to move easily from one place to another.
- Laptops: 10-16 pounds in weight
- Notebooks: 5-10 pounds in weight
- Subnotebooks: 2-6 pounds in weight
- Personal Digital Assistants: Also known as palmtop computers and handheld PCs. They combine pen input, writing recognition and communication capabilities such as iphone 5, samsung galaxy s3 stc
- They are desk size machines.
- They fall between microcomputers and mainframe computers in their processing speeds and data-storing capabilities.
- They might be used for research or monitoring a particular manufacturing process.
- Smaller companies have been using minicomputers for their data processing needs such as accounting/billing systems.
3 Mainframe Computers
- These are large computers.
- They are capable of great processing speeds and data-storing.
- They are used by large organizations – business, banks, government agencies etc – to handle millions of transactions.
- For example, airline companies use mainframe computers to process information about millions of travelers.
- The most powerful type of computer is the supercomputer.
- These machines are special, high-capacity computers used by very large organizations.
- For example, NASA uses supercomputers to track and control space explorations.
- Supercomputers are also used for oil exploration, simulations and worldwide weather forecasting.