How Computers Work

A general purpose computer has four main sections: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by busses, often made of groups of wires.
The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor.

• CPU design and Control unit-The control unit (often called a control system or central controller) directs the various components of a computer. It reads and interprets (decodes) instructions in the program one by one. The control system decodes each instruction and turns it into a series of control signals that operate the other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance.A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from.
  
  Diagram showing how a particular MIPS architecture instruction would be decoded by the control system.
  The control system's function is as follows—note that this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:

History of Computing

• It is difficult to identify any one device as the earliest computer, partly because the term "computer" has been subject to varying interpretations over time. Originally, the term "computer" referred to a person who performed numerical calculations (a human computer), often with the aid of a mechanical calculating device.


• The history of the modern computer begins with two separate technologies - that of automated calculation and that of programmability.


• Examples of early mechanical calculating devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC). The end of the Middle Ages saw a re-invigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers. However, none of those devices fit the modern definition of a computer because they could not be programmed.
• Hero of Alexandria (c. 10 – 70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions - and when.This is the essence of programmability. In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.
  It was the fusion of automatic calculation with programmability that produced the first recognisable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".Due to limited finances, and an inability to resist tinkering with the design, Babbage never actually built his Analytical Engine.

Computer

A computer is a machine that manipulates data according to a list of instructions.

Computers take numerous physical forms. The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers. Modern computers are based on comparatively tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space.Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers in various forms are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.
The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.

Basic Information Technology Concepts

• Data-refers to a collection of organized information, usually the results of experience, observation or experiment, or a set of premises. This may consist of numbers, words, or images, particularly as measurements or observations of a set of variables.
• Database- computer database is a structured collection of records or data that is stored in a computer system. A database usually contains software so that a person or program can use it to answer queries or extract desired information.[1] The term "database" refers to the collection of related records, and the software should be referred to as the database management system (DBMS). Other terms for DBMS are database manager or database system. When the context is ambiguous, however, many database administrators and programmers use the term "database" to refer to both the data collection and the software that enables it to be accessed.
• Information-as a concept bears a diversity of meanings, from everyday usage to technical settings. Generally speaking, the concept of information is closely related to notions of constraint, communication, control, data, form, instruction, knowledge, meaning, mental stimulus, pattern, perception, and representation.
• Information science-is an interdisciplinary science primarily concerned with the collection, classification, manipulation, storage, retrieval and dissemination of information.Information science studies the application and usage of knowledge in organizations, and the interaction between people, organizations and information systems. It is often (mistakenly) considered a branch of computer science. It is actually a broad, interdisciplinary field, incorporating not only aspects of computer science, but also mathematics, library science, cognitive science, and the social sciences.
• Information technology-as defined by the Information Technology Association of America (ITAA), is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware." IT deals with the use of electronic computers and computer software to convert, store, protect, process, transmit and retrieve information, securely.

List of Basic Information Technology Topics

The following list of topics is provided as an overview of and introduction to information technology:

• Branches of information technology
• History of information technology
• Basic information technology concepts
• Information technology scholars
• Leaders in information technology
• Information technology lists

The Information Technology (IT) Portal

Information technology (IT) or information and communication technology (ICT) is a broad subject which deals with technology and other aspects of managing and processing information, especially in large organizations. Particularly, IT deals with the use of electronic computers and computer software to convert, store, protect, process, transmit, and retrieve information. Over the past 20 years, its prevalence has dramatically increased so that it is now a part of nearly every aspect of daily life.

Information technology (IT), as defined by the Information Technology Association of America (ITAA), is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware." IT deals with the use of electronic computers and computer software to convert, store, protect, process, transmit and retrieve information, securely.

Today, the term information technology has ballooned to encompass many aspects of computing and technology, and the term is more recognizable than ever before. The information technology umbrella can be quite large, covering many fields. IT professionals perform a variety of duties that range from installing applications to designing complex computer networks and information databases. A few of the duties that IT professionals perform may include data management, networking, engineering computer hardware, database and software design, as well as the management and administration of entire systems. when computer and communications technologies are combined, the result is information technology, or "infotech". information technology (IT) is a general term that describes any technology that helps to produce, manipulate, store, communicate, and/or dissemenate information.