Computers World

Electro-Machanical Computer

2009-11-05T03:02:00.000-08:00

Mark-I

* Designed by Howard Aiken (1900-1973), a Harvard Engineer in 1937.
* It was the first automatic electromechanical computer.
* It was 51 ft. long, 8 ft. tall and 3 ft. wide having 18000 vaccum tubes.
* It used instructions stored in paper tapes and panched cards.
* It consits of 7 lakhs 50 thousands parts.

ABC(Atnosoft-Berry Computer)

* First ecletromechanical digital computer.
* Built in 1937-1942 at Lowa State University by john V. Atanasoft and Clifford Berry.
* It Introduce the ideas of binary arithmetic and logic circut.
* It used punch cards as secondy Storage.

History and Evolution of computer

2009-11-04T01:07:00.000-08:00

1Mechinical Calculation Devices

a> Abcaus:-
*Created by Chinese about 30000 years ago.
*The first meachanical aid to calculations. *Calculations are performed by manipulating the
beads.
*It is a rectangular box. Divided into two parts by mid bar. upper part is called heaven consist of
two.

b> Napier's Bones:-
*Created by John Napier(1550-1617), a Scottish mathematician and scientist.
*The first multiplication mechanical aid to calculations.
*There are 9 different “bones” are used.

c> Slide Rule:-

* Invented by William Oughtred(1574-1660), an English Mathematician in 1620.
* An analog device used the principle of logaritms.
* Could perform simple multiplication and divison problems.
* Consist of 2 grdduated scales, devised in such a way that suitable alignment of one againt other
makes it possible to obtain products, quotients etc.

d> Pascaline:-

* Developed by Blaise Pascale(1623-1662) in 1642 to help his father's tax work.
* It contain eight dials, gears and wheels.
* It was capable of performing additions and subtractons up to 8 digits.
* It could add and subtract by the movement of wheels, not used for devision and multiplication.

Stepped Reckoner:-

* Developed by Gottfried Wilhelm Von Leibniz(1646-1716), a German Mathematican &
philosopher in 1694.
* It could evaluate square roots by series of stepped addition.
* The centerpiece of this machine was its stepped-drum gear design.
* Could perform all four of the basic arithmetic functions-addition, subtraction, multiplicatio
and division.

Difference Engine:-

* Design by Charles Babbage(1792-1871) an English mathmatematician, in 1822.
* It could slove equations.
* This project could not be completed due to lack of funds.
* It is housed in the Science Museum, London and all is till in perfect working order.

Analytical Engine:-

* Developed by Charles Babbage in 1833.
* It had store for storing data and introduction result.
* It had an output device to produce printed result.
* It had a unit for calculation 'mill'.
* All the morden computers are based on analytical engine(input-process-output).

Hollerith Tabulator:-

* Developed by ana American Dr. Hermam Hollerith(1869-1926) in 1887.
* It Used punched cards for input, output and instructions.
* This machine was used by American Department of Census.
* In 1886, he founded the tabulating machine company which was renamed as IBM
(International Business Machine) later.

Charles Babbage(1792-1871)

* A professor of mathematics developed a machine called Difference Engine in 1822.
* In 1833, he developed the Analytical Engine.
* He is known as the Father of the morden computer as his invention Analytical Engine had
the work for more of the characteristics of morden computers.

Lady Augusta Add Lovelace(1816-1852)

* An English Mathematician (daughter of English Poet Lord Byron) carried forward yhr work of
Charles Babbage.
* She developed programes for performing mathematical calculation on the Analytical Engine.
* She was first computer programmer.
* One programming language 'Ada' was named after her.

Jon Von Neumann

* He was the doctorate in mathematics from the University of Budapest on set theory.
* He designed the EDVAC with team of J.P Eckert and J.W. Mauchly.
* He introduced the concept of having a stored programe in memory in 1945.
* This concept led to the beginning of the first generation of the computers.

Application of Computer

2009-11-03T23:36:00.000-08:00

Computer use in large areas such as banking , education, hospital, industries, research, hospital, data procesing, science and technology, offices, railways, advertisement, communication, library, simulation, weather forecasting etc.

Banking and Financial Company- Computer are used in the bank and financial company for electronic money transfer, statistical repoat, voucher, ldger, balabce sheet etc.
Education - Computer can be used as teaching learning tool, result processing, students' data processing, question prepration, handouts and note preparation etc.
Industries- Industrial research, budgeting, process contorl all are computer based in morden industries.
Hospital- In hospitals, computer are applied in medicine, surgery, research, diagnose, disease etc.
Science and Engineering- Computer is strong tool for every branch of engineering such as civil, electrical, aeronautic etc.
Advertisement- Computer are used for advertisement such as business advertisement, film adertisement. It is also used to make cartoon films, special effects and image processing.
Communication- E-mail, e-fax, internet etc are computer based communocations. The computera and internet is the backbone of recent communication.
Library-Coimputer software are used for the management of library. Computer used for keeping books, borrowing books, updating the records etc.

Disadvantage of computer

2009-11-03T03:22:00.000-08:00

Computer is expensive and still not affordable.
Repair and maintenance is required ferquently.
People are becoming too much dependent on computers.
Very difficult to maintain the privacy.
Skilled user is required to work with the computer.
Computer cannot be used on the dursty and the rough envourmment.
porn stuff.
Sopil eye sight if look on the moniter.
Illegal work can ruin business.
Computer can be hancked hence important information is no longer as safe computer useb to be.
computer really on electricity such as limit their reliability.

Advantage of computer

2009-11-03T02:46:00.000-08:00

Computer is a reable machine and performs the task with 100% accurancy rate.
Copmaring with human being its must faster.
Computer can be veru useful while doing repeated tasks.
Computer is versatile as it can di many types of jobs once at a time.
lower total cost of ownership.
Reduced dependance on software vendors.
High level of security.
Easier to customize.
Computer are tools like spelling and grammar check
Do not see a significent advantage.
On the move
Back- up copies of works can be made easily, without having to-write every thing.
Computer contain many programe that allow you tom present a pice work in a professional manner.
Computer provide us Entertainment

Limitation of computer

2009-11-03T02:09:00.000-08:00

Although computer are very useful device and appilied and varius fields but there are limitation of computer.

Computer does not have its own intelligency. computer is dull machine.
computer can not memorize and recall an needed by it.
Instructions are needed to perform any task

Capabilities and capability-based security

2009-11-03T00:01:00.000-08:00

It performs compution at enourmous speed wirh 100% accuracy rate.It perform provides job repeatedly without dart and tired.It provides us information while can used in future for different purpose. the only exception is "at most one special type of capability system ",in which the manipulation of capabilites must be done by be believe hardware. A capability is defined to a protected object reference which, by virture of its possession by a user process. Capability-based security is a concept in the design of secure computing systems. A capability (known in some systems as a key) is a communicable, unforgivable token of authority. A user program on a capability-based operating system must use a capability to access an object. Capabilities are typically stored by the operating system in a list, with some mechanism in place to prevent the program from directly modifying the contents of the capability (so as to forge access rights or change the object it points to).At last , when a capability propagates between compartments, security policy and identities must be checked.

Characteristic of computer

2009-10-30T02:34:00.000-07:00

Speed:

computer can perform very complex calculations at very enormous speed. generally, the speed of computer is measured in terms of fraction of speed.

Millisceonds-One thousendth of a second(1/1000).

Microsecond-One millionth of a second (1/1000000).

Nanosecond-One billionth of a second (1/1000000000).

Picosecond-One trillionth of a second (1/1000000000000).

Storage:

A computer system can store a huge amount of information which may be

used as future refresh. Few storage devices are Hard disk, CD-ROM.

Pen derive etc. The storage capacity is measured interims of :

8bits 1 Byte

1024 Bytes 1 Killobyte

1024 Kilobytes 1 Megabyte

1024 Megabytes 1 Gigabyte

1024 Gigabytes 1 Terabyte

Accurancy:

Computer always perform its takes without makieng any mistake if the instruction is

provide correctly. So the accurancy of a computer is cent percent.

Versatility:

Computer has a wide range of application and is used indifferent fields such as education

Science & technology, astronomy, business, entertainment. medicinies etc.

Diligence:

Copmuter is capable of doing the required tasks again without affecting its speed,

accuracy and efficiency.

Non-intelligent

Copmuter is a dumb machine and it cannot do any work without instruction from the user. So a computer cannot take its own decision as we can

Definition of computer

2009-10-29T02:56:00.000-07:00

Computer is an programmable machine. computer is an electronic machine which can accept row material data and process then give instruction. Today, however, the term is most often used to refer to the desktop computer and laptop computer the most people use. Complex computer also include the means for storing data(including the program which is also a form of data) for some necessary duration. A program, be invariable and built into the computer(and called logic circuitry as it is on microprocessor) or different different program may be provide the computer. (loaded into its storage and then start by an administration or user). When referring to a desktop model, the term "computer" technically only refers to the computer it seat -- not the monitor, keyboard and mouse.

The main characteristic of a computer are:

It responds to a set of instruction provided from an input device.
It process the provided set of instruction
It gives out the meaningful result after processing the instruction.