Introduction to Information Technology

Information technology (IT) is the use of computers, storage, networks and software to create, process, store, secure and exchange information. The computer is at its heart: an electronic device that accepts data (input), processes it under the control of stored instructions (program), stores it and produces results (output). This note covers what a computer is, how it evolved, how it is organised and classified, and what it can and cannot do.

Key concepts

Definition – computer comes from "compute" (to calculate). Data = raw facts; information = processed, meaningful data. The IPO cycle: Input → Process → Output, with Storage.

Characteristics of a computer

• Speed – operations in microseconds (10⁻⁶ s), nanoseconds (10⁻⁹ s) and picoseconds (10⁻¹² s).
• Accuracy – errors are almost always human or program errors (GIGO: Garbage In, Garbage Out).
• Diligence – no fatigue or loss of concentration.
• Versatility – many different tasks.
• Storage/memory – large capacity, fast retrieval.
• Automation – runs stored programs without intervention.
• No IQ / no feelings – cannot think or make judgements on its own.

Evolution of computers

Year	Device	Person
Ancient	Abacus	Mesopotamia/China (exact origin uncertain)
1617	Napier's bones	John Napier
1642	Pascaline (adding machine)	Blaise Pascal
1671/1694	Stepped reckoner (multiplication)	Gottfried Leibniz
1801	Punched-card loom	Joseph Jacquard
1822/1834	Difference Engine / Analytical Engine	Charles Babbage ("father of computers")
1840s	First algorithm for the Analytical Engine	Ada Lovelace (first programmer)
1890	Tabulating machine (US census)	Herman Hollerith
1944	Mark I (electromechanical)	Howard Aiken
1946	ENIAC (first general-purpose electronic)	Eckert & Mauchly
1949	EDSAC (early stored program)	Maurice Wilkes
1951	UNIVAC I (first commercial computer in the USA)	Eckert & Mauchly
John von Neumann proposed the stored-program concept (EDVAC report, 1945). In Nepal, an IBM 1401 was brought for processing the census of 2028 BS (1971 AD).

Block diagram – Input unit → CPU (ALU + Control Unit + registers) ↔ Memory unit (primary and secondary) → Output unit. ALU does arithmetic/logic; CU directs and coordinates all units; memory stores data and instructions (von Neumann architecture).

Generations of computers

Generation	Period (approx.)	Technology	Language	Examples
1st	1940–1956	Vacuum tubes	Machine language	ENIAC, UNIVAC
2nd	1956–1963	Transistors	Assembly, early FORTRAN/COBOL	IBM 1401, IBM 7090
3rd	1964–1971	Integrated circuits (SSI/MSI)	High-level languages, OS	IBM 360, PDP-8
4th	1971–present	Microprocessors (LSI/VLSI)	GUI, 4GL	Intel 4004, PCs
5th	Present & future	ULSI, AI, parallel processing	Natural language, AI	Expert systems, robots
The transistor was invented in 1947 at Bell Labs; the first microprocessor was Intel 4004 (1971).

Classification of computers

• By working principle: analog (continuous quantities – speedometer, thermometer), digital (discrete binary data), hybrid (both – e.g. ICU patient monitors).
• By size/capacity: supercomputer (fastest; weather forecasting, research; measured in FLOPS), mainframe (large organisations, many users – banks), minicomputer (mid-range), microcomputer (personal: desktop, laptop, tablet, smartphone).
• By purpose: general-purpose and special-purpose (embedded).

Applications – education (e-learning), banking (ATM, online banking), business, health (diagnosis, records), engineering (CAD/CAM, simulation), science/weather, government (e-governance, national ID), communication, entertainment, transport (ticketing, GPS), agriculture.

Capabilities and limitations – capabilities: speed, accuracy, storage, repetition, communication. Limitations: no intelligence or common sense, cannot decide on its own, depends on instructions and correct input, no emotions, needs power and maintenance, vulnerable to viruses and hardware failure.

High-yield points

• Babbage = father of the computer; Ada Lovelace = first programmer.
• Von Neumann: stored-program concept (EDVAC report, 1945).
• ENIAC (1946) = first general-purpose electronic computer; UNIVAC I (1951) = first commercial in the USA.
• Generations: vacuum tubes → transistors → ICs → microprocessors (VLSI) → AI/ULSI.
• First microprocessor: Intel 4004 (1971); transistor invented 1947 at Bell Labs.
• CPU = ALU + Control Unit + registers.

Exam tips

• Charles Babbage = father of the computer; Ada Lovelace = first programmer; von Neumann = stored-program concept.
• Generation technology chain: vacuum tube → transistor → IC → microprocessor → AI/ULSI.
• Hybrid computers combine analog and digital features.
• ALU + CU (+ registers) = CPU; memory is a separate unit in the block diagram.
• GIGO means output quality depends on input quality.

Exam-style questions

From Calmon's question bank, which has 25 questions on this topic.

1. The use of VLSI technology and the microprocessor is the characteristic feature of which generation of computers?

• A. First generation
• B. Third generation
• C. Fourth generation
• D. Second generation

Answer: C. Fourth-generation computers use VLSI chips, with the entire CPU on a single microprocessor; transistors marked the second and ICs the third generation.

2. A computer that combines the features of both analog and digital computers, such as one used in an intensive care unit, is called a:

• A. Hybrid computer
• B. Microcomputer
• C. Mainframe computer
• D. Supercomputer

Answer: A. Hybrid computers process continuous (analog) measurements and convert them to digital form for processing, combining the advantages of both types.

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