Mark-I

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

Jon Von Neumann

• Jon Von Neumann was the doctorate in mathematics from the University of Budapest on set theory.


• Jon Von Neumann designed the EDVAC with team of J.P Eckert and J.W. Mauchly.


• Jon Von Neumann 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.

Lady Augusta Add Lovelace(1816-1852)

• An English Mathematician (daughter of English Poet Lord Byron) carried forward yhr work ofCharles 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.

Charles Babbage(1792-1871)

• A professor of mathematics developed a machine called Difference Engine in 1822.
• In 1833, Charles Babbage developed the Analytical Engine.
• Charles Babbage is known as the Father of the morden computer as his invention Analytical Engine hadthe work for more of the characteristics of morden computers.

Hollerith Tabulator

• Developed by ana American Dr. Hermam Hollerith(1869-1926) in 1887.
• Hollerith Tabulator 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.

Analytical Engine

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

Difference Engine

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

Stepped Reckoner

• Developed by Gottfried Wilhelm Von Leibniz(1646-1716), a German Mathematican &philosopher in 1694.
• Stepped Reckoner 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, multiplicatioand division.

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.

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 othermakes it possible to obtain products, quotients etc

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.

Abcaus

• Created by Chinese about 30000 years ago.
• The first meachanical aid to calculations.
• Calculations are performed by manipulating thebeads.
• It is a rectangular box. Divided into two parts by mid bar.
• upper part is called heaven consist oftwo.
  
  

History and Evolution of computer

• Abcaus
• Napier's Bones
• Slide Rule
• Pascaline
• Stepped Reckoner
• Difference Engine
• Analytical Engine
• Hollerith Tabulator
• Charles Babbage
• Lady Augusta Add Lovelace(1816-1852)
• Jon Von Neumann

Advantage of computer

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

Disadvantage of computer

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

Capabilities and capability-based security

Capabilities and capability-based security 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.

Limitation of computer

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

Characteristic of computer

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

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.