History of calculators and computers, input, output and memory.

Graphics tablet

Allows people to draw things by hand using a pen named Stylus. The picture generally does not appear on its screen, but on the computer monitor. It is used by artists, graphic designers and illustrators.

Analytical engine.

Also invented by Charles Babbage. It included input, output and memory devices.

Secondary memory

Also known as external memory. It has different devices which belong to it. All devices are non volatile.

Order of units of memory

Bit 8 bits= 1 byte (B) 2024 Bytes= 1 Kilobyte (KB) 2024 Kilobytes = 1 megabyte(MB) 2024 Megabytes= 1 Gigabyte (GB) 2024 Gigabytes= 1 terabyte (TB) 2024 terabytes= 1 petabyte (PB) 2024 petabytes= 1 yottabyte (YB)

First generation of computers

From 1940-1958. They used vacuum tubes. They were very big, had small internal storage, we're very expensive and hard to program.

Second generation of computers

From 1959-1964. They used Transistors. They were smaller, faster, cheaper and more efficient than the first generation computers. They relied on punched cards for input, and programming languages like COBOL and FORTRAN came to use. Examples include IBM 1401 and RCA 501.

Third generation of computers

From 1965-1970. They used Integrated Circuits (chips). They were smaller, faster, cheaper and more efficient than the second generation computers. Examples include IBM 360 & 370 series.

Fourth generation of computers

From 1971-present. We use Microprocessors. They are smaller, much faster, cheaper and more efficient than the third generation computers. Examples include IBM PC and Apple Macintosh.

Fifth generation of computers

From 1989-future. They are referred to as supercomputers. They use Artificial Intelligence, and the goal is for computers to overcome their lack of taking decisions on their own and reacting to things like humans. Examples include CRAY CS 300 and Sophia ( the robot)

EDSAC

Full form: Electronic Delay Storage Automatic Calculator. Invented by Professor M. Wilkes in 1949. It was the first electronic computer that used stored programs.

EDVAC

Full form: Electronic Discrete Variable Automatic Computer. Invented by John Presper Eckert & John W. Mauchly in 1944. It's development got delayed and it was finished in 1948.

ENIAC

Full form: Electronic Numerical Integrator and Computer. Invented by John Presper Eckert and John W. Mauchly in 1946. It was the first electronic digital computer.

UNIVAC 1

Full form: Universal Automatic Computer. Invented by John Presper Eckert & John W. Mauchly in 1951.

Touch screen

Input device that lets the user touch areas of the display to perform tasks. It is used in ATMs, in tablets, railway and airport terminals, etc.

Mark 1

Invented by Howard H. Aiken in 1944. It was the first fully automatic calculator.

Pen drive (flash drive)

It has various storage capacities, e.g. 1 GB, 2 GB, 4 GB, 8 GB, 16 GB, 32 GB, etc. It is used to read, transfer and delete data. Many people use it as it is small enough to carry in your pocket. To use it, you need a USB port.

Read only memory (ROM)

It is non volatile, it doesn't lose the data after the computer is switched off. It can be written only once, and then only be read. There are different types of ROM: PROM= Programmable read only memory. It can be rewritten once again. EPROM= Erasable read only memory. It can be erased using ultra violet light EEPROM= Electrically erasable programmable read only memory. It can be erased using electrical signals

Primary memory (internal memory)

It is the main area where data, instructions and information are stored. It is also called RAM (random access memory). RAM is also called read/write memory as you can edit and read it as often as you like. It is volatile, that means it loses all data after the computer is switched off.

Abacus.

It is the oldest calculator. It is a wooden frame with beads sliding on wires. It is used for addition, subtraction, multiplication and division. It is still used in some places, especially Africa and Asia.

Pascaline

It was invented by Blaise Pascal in 1641, and was the first mechanical calculator. It consisted of a large rectangular box with movable wheels. It was used to add, subtract, multiply and divide numbers up to hundreds and thousands.

Difference engine

It was invented by Charles Babbage in the 19th century. It was used to prepare mathematical tables.

Napier's Bones

It was invented by Sir John Napier in 1616. It was used for addition, subtraction, multiplication, division and finding the square root of a number. It is called the Napier's Bones because numbers were carved on bones or strips of wood.

DVD

It's full form is digital video disc or digital versatile disc. It stores up to 4.7 GB if data. It looks similar to a CD. To use it, you need a DVD-ROM on your computer.

Visual Display Unit

VDU is the short form. It is also known as a monitor. It's output is known as soft copy. It is measured diagonally we have 11 inch, 14 inch, 15 inch, 17 inch, 19 inch, 21 inch, 22 inch and 24 inch monitors.

Impact printer

a printer that uses keys or pins to strike an ink ribbon to create an image on paper

Non impact printer

forms characters and graphics on a piece of paper without actually contacting the paper. In an Injekt Printer, the printhead Sprays tiny drops of ink on a paper.