Lesson Notes By Weeks and Term - Senior Secondary School 1

TERM: 1^st Term

WEEK: 2

CLASS: S.S. 1

DATE:

SUBJECT: Computer Science
TOPIC: History of computer

The development of the first counting device has been dated to ancient times, a man called abacus used a counting device about 3000 years ago and from this time and man has continued to improve. Ancient methods of counting were through the use of fingers, stones, sticks and grains.

The history of computer science began long before the modern discipline of computer science that emerged in the 20th century, and hinted at in the centuries prior.The progression, from mechanical inventions and mathematical theories towards the modern computer concepts and machines, formed a major academic field and the basis of a massive worldwide industry.

The earliest known tool for use in computation was the abacus, developed in period 2700–2300 BCE in Summer . The Sumerians’ abacus consisted of a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system. Its original style of usage was by lines drawn in sand with pebbles. Abaci of a more modern design are still used as calculation tools today

Charles Babbage is described as the ‘Father of Computer’. Charles Babbage, an English mechanical engineer and polymath, originated the concept of a programmable computer. Considered the “father of the computer”, he conceptualized and invented the first mechanical computer in the early 19th century. After working on his revolutionary difference engine, designed to aid in navigational calculations, in 1833 he realized that a much more general design, an Analytical Engine, was possible. The input of programs and data was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. The Engine incorporated an arithmetic logic unit, control flow in the form of conditional branching and loops, and integrated memory, making it the first design for a general-purpose computer that could be described in modern terms as Turing-complete.

Mechanical devices

1. Abacus: It is the earliest form of computing system and was produced by the Chinese in the early age. It is made up of a frame, iron and beads in between them. They are used for counting and calculating. Also functions in adding and subtracting.
2. Slide rule: This is used for performing operation which involves multiplication and division.

Slide rule

Abacus

Electronic devices

1. Pascal’s calculating machine: Blaise Pascal invented a hand operated calculator. This was operated by turning dials.
2. Charles Babbage: He was credited for the invention of modern computer and he was also called the Father of Computer. The machines he invented are called the “difference machine” and the ‘Analyte machine’. In 1930, he used these machines to solve mathematical equations.

charles babbage Analyte machine

Pascal’s calculating machine

The various generations of computers are listed below

(i) First Generation (1946-1954): In 1946 there was no ‘best’ way of storing instructions and data in a computer memory. There were four competing technologies for providing computer memory: electrostatic storage tubes, acoustic delay lines (mercury or nickel), magnetic drums (and disks?), and magnetic core storage.

The digital computes using electronic valves (Vacuum tubes) are known as first generation computers. The first ‘computer’ to use electronic valves (i.e. vacuum tubes). The high cost of vacuum tubes prevented their use for main memory. They stored information in the form of propagating sound waves.

The vacuum tube consumes a lot of power. The Vacuum tube was developed by Lee DeForest in 1908. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were: Mark I (electro-mechanical computer) built in 1944, ENIAC (First general purpose electronic computer) built in 1946, EDVAC (binary serial computer) built in 1950, EDSAC (first stored-program computer) built in 1949, UNIVAC (First Commercial Computer) built in 1951.

Other Important Computers of First Generation

Some other computers of this time worth mentioning are the Whirlwind, developed at Massachussets Institute of Technology, and JOHNNIAC, by the Rand Corporation. The Whirlwind was the first computer to display real time video and use core memory. The JOHNNIAC was named in honor of Jon Von Neumann. Computers at this time were usually kept in special locations like government and university research labs or military compounds.

Limitations of First Generation Computer

Followings are the major drawbacks of First generation computers-

1. They used valves or vacuum tubes as their main electronic component.
2. They were large in size, slow in processing and had less storage capacity.
3. They consumed lots of electricity and produced lots of heat.
4. Their computing capabilities were limited.
5. They were not so accurate and reliable.
6. They used machine level language for programming.
7. They were very expensive.

Example: ENIAC, UNIVAC, IBM 650 etc

ENIAC – Electronic Numerical Integrator and Calculator/Computer: This was developed by John Mauchly and J.  Presper Eckert at the school of engineering of the university of Pennsylvania in 1946. It was the prototype from which most other modern computers evolved. ENIAC contained 17,648 vacuum tubes, 7,200 crystal diodes, 7,000 resistors, 1,500 relay, 10,000 capacitors and 60,000 manual switches and consumed 150watts of power. It has thirty separate unit power supply and forced air cooling. ENIAC also had a functioning unit that was equipped with local program control circuits and store a minimum of twenty 10digit decimal number. It uses card reader for input, card punch for output and the 1500 associated relays. ENIAC is used for arithmetic operations and to calculate the trajectory of artillery shells.

Eniac computer

UNIVAC – Universal Automatic Computer:  This was the world’s first commercially available computer developed by the same designers of ENIAC. It was used for general purpose computing with large amounts of input, output and storage capacity compared to earlier machines. UNIVAC was the first computer to come equipped with a magnetic tape unit and it is also the first computer to use buffer memory. It contains 5600 tubes, 18000 crystal diodes and 300 relays, internal storage capacity of 100 words or 1200 characters.

Univac Computer

(ii)  Second Generation (1955-1964): The second-generation computer used transistors for CPU components & ferrite cores for main memory & magnetic disks for secondary memory. They used high-level languages such as FORTRAN (1956), ALGOL (1960) & COBOL (1960 – 1961). I/O processor was included to control I/O operations.

Around 1955 a device called Transistor replaced the bulky Vacuum tubes in the first generation computer. Transistors are smaller than Vacuum tubes and have higher operating speed. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.

It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were

1. IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.
2. IBM 1401: Its size was small to medium and used for business applications.
3. CDC 3600: Its size was large and is used for scientific purposes.

Features:

1. Transistors were used instead of Vacuum Tube.
2. Processing speed is faster than First Generation Computers (Micro Second)
3. Smaller in Size (51 square feet)
4. The input and output devices were faster.

Example: IBM 1400 and 7000 Series, Control Data 3600 etc.