The word ‘computer’ comes from the word compute which means ‘to calculate’. Computers were developed from calculators as the need arose for more complex and scientific calculations. Charles Babbage is known as the father of computers because of his immense contribution to the world of programming. His idea was soon developed into a programmable computer that could calculate and print logarithmic tables with huge precision. But there were many practical problems and the progress was slow. MEANING AND DEFINITION:
An electronic device which is capable of receiving information (data) in particular form and of performing a sequence of operations in accordance with predetermined but variable set of procedural instructions (program) to produce a result in the form of information or signals. a person who makes calculations, especially with a calculating machine. The physical components from which a computer is constructed (electronic circuits and input/output devices) are known as “hardware”. Most computers have four types of hardware component: CPU, input, output and memory. The CPU (central processing unit) executes programs (“software”) which tell the computer what to do. Input and output (I/O) devices allow the computer to communicate with the user and the outside world. There are several kinds of memory – fast, expensive, short term memory (e.g. ram) to hold intermediate results, and slower, cheaper, long-term memory (e.g. magnetic disk and magnetic tape) to hold programs and data between jobs. GENERATION OF COMPUTERS:
Each generation of computers is characterized by major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices. Read about each generation and the developments that led to the current devices that we use today. First Generation – 1940-1956: Vacuum Tubes
The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. A magnetic drum, also known as drum, is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Magnetic drums were once used as a primary storage device but have since been implemented as auxiliary storage devices. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
First generation computers relied on machine language to perform operations, and they could only solve one problem at a time. Machine languages are the only languages understood by computers. While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers. Computer Programmers, therefore, use either high level programming languages or an assembly language programming. An assembly language contains the same instructions as a machine language, but the instructions and variables have names instead of being just numbers. The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. Second Generation – 1956-1963: Transistors
Transistors replaced vacuum tubes and ushered in the second generation computer. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today’s latest microprocessor contains tens of millions of microscopic transistors. The transistor was invented in 1947 but did not see widespread use in computers until the late 50s.
The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output. Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
Third Generation – 1964-1971: Integrated Circuits
The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers. Silicon is the basic material used to make computer chips, transistors, silicon diodes and other electronic circuits and switching devices because its atomic structure makes the element an ideal semiconductor. Silicon is commonly doped, or mixed, with other elements, such as boron, phosphorous and arsenic, to alter its conductive properties. A chip is a small piece of semi conducting material(usually silicon) on which an integrated circuit is embedded. A typical chip is less than ¼-square inches and can contain millions of electronic components(transistors). Computers consist of many chips placed on electronic boards called printed circuit boards.
Fourth Generation – 1971-Present: Microprocessors
The microprocessor brought the fourth generation of computers, as thousands of integrated circuits we rebuilt onto a single silicon chip. A silicon chip that contains a CPU. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles. Three basic characteristics differentiate microprocessors:
* Instruction Set: The set of instructions that the microprocessor can execute.
* Bandwidth: The number of bits processed in a single instruction.
* Clock Speed: Given in megahertz (MHz), the clock speed determines how many instructions per second the processor can execute.
Fifth Generation – Present and Beyond: Artificial Intelligence
Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.
Artificial Intelligence is the branch of computer science concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial intelligence includes:
* Games Playing: programming computers to play games such as chess and checkers
* Expert Systems: programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms)
* Natural Language: programming computers to understand natural human languages
* Neural Networks: Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains
* Robotics: programming computers to see and hear and react to other sensory stimuli. TYPES OF COMPUTERS:
The types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word “computers” reminds one of the desktop computers used in offices or homes. Different categories of computes have been devised in keeping with our varied needs. Analog Computers:
The analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. It is also unique in terms of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation. Hybrid computers:
These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of “0” and “1” can give very precise results. But the problem is that they are too slow and incapable of large scale mathematical operation. In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control. Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers: The Mainframe Computer –
These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously. The Microcomputer –
These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows: * Personal Digital Computer
* Tablet PC
* Work Stations
* Hand Held Computers.
The Mini computer –
Mini computers like the mainframe computers are used by business organization. The difference being that it can support the simultaneous working of up to 100 users and is usually maintained in business organizations for the maintenance of accounts and finances. The Super computers-
It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced. TYPES OF HARDWARE:
* RANDOM ACCESS MEMORY (RAM)
* CENTAL PROCESSING UNIT(CPU)
* POWER SUPPLY UNIT
* MISCELLANEOUS COMPUTER HARDWARE
This is the most important type of computer hardware. It is a circuit board, whereon different parts of the system are set up. All input devices work when they are connected to the motherboard. RAM, CPU, and other crucial peripherals are installed on the computer motherboard. It helps to run the whole computer system. RANDOM ACCESS MEMORY (RAM)
The RAM is a small chip that fits on the motherboard. It does the job of storing data on a temporary basis. RAM chips are generally available from 256 MB to 6 GB or more and are upgradeable. The more the RAM, the faster the computer system will function.
CENTRAL PROCESSING UNIT (CPU)
The CPU is a small chip installed on the motherboard that does the job of running computer programs. It is more commonly referred to as the computer processor. The speed of computer functioning also depends a lot on the processor’s capacity. Without the CPU, you will not be able to play games, browse the web, or run any other applications on the system. The hard drive is where all the program files are stored for retrieval or further operation. There are many storage capacities of hard drives which normally range from 80 GB to 1 TB or more. External hard drives are also available nowadays with a storage capacity of around 8 TB. POWER SUPPLY UNIT
As the name suggests, this device is responsible for providing the system with power to function. It is an electrical box fitted inside at the back of the cabinet, which connects to and powers the motherboard, disk drives, and other similar components. It also has a fan for cooling purpose in case of overheating.
MISCELLANEOUS COMPUTER HARDWARE
The above mentioned hardware was only the basic ones. There are many other parts which can be considered as computer hardware. The floppy drive is one hardware component that accepts the floppy for data processing. These are just a few of the different types of hardware devices used in information technology. There are many others such as audio and video graphic cards, router, modem, PCI cards, cabinet, etc.
TYPES OF COMPUTER SOFTWARE
Computer software is a general term used to describe a collection of computer programs, procedures and documentation that perform some task on a computer system. The term includes application software such as word processors which perform productive tasks for users, system software such as operating systems, which interface with hardware to provide the necessary services for application software, and middleware which controls and co-ordinates distributed systems. Practical computer systems divide software systems into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred. * System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, windowing systems, utilities and more. The purpose of systems software is to insulate the applications programmer as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such accessory devices as communications, printers, readers, displays, keyboards, etc.
* Programming software usually provides tools to assist a programmer in writing computer programs and software using different programming languages in a more convenient way. The tools include text editors, compilers, interpreters, linkers, debuggers, and so on. An Integrated development environment (IDE) merges those tools into a software bundle, and a programmer may not need to type multiple commands for compiling, interpreter, debugging, tracing, and etc., because the IDE usually has an advanced graphical user interface, or GUI. * Application software allows end users to accomplish one or more specific (non-computer related) tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. Businesses are probably the biggest users of application software, but almost every field of human activity now uses some form of application software. It is used to automate all sorts of functions. INPUT DEVICES
Input devices are what is used to put data into the computer. Without them you could not tell the computer what to do. Keyboard: The most commonly used input device. Some keyboards are specially designed to help people with disabilities.Mouse: Used to control a pointer and to select items. A very user-friendly device.| |
This is like an upside down mouse where the user rolls the wheel in the direction they want the pointer to go. This is useful when there is no flat surface to use a mouse on. They are often used with video games and information kiosks.
Used instead of a mouse on most laptop computers. It is a touch sensitive pad that the user moves their finger along in the direction they wish the pointer moves.
Often used for playing games and for simulators. They can move in 8 directions and often have buttons attached for extra functionality.
Used for Computer Aided Design (CAD) and other graphics work. It is a flat, pressure senstive board that you press on with a special pen. It makes it easier to draw, just like using a pen or pencil.
Touch Sensitive Screen: There are two types:
1. Often used on information kiosks and gaming machines where your finger touches the screen, breaking an invisible infra red grid. The computer can tell where your finger is by which beams are broken and sends this informaton to the computer.
2. Used on palmtop and tablet computers where a flat screen is pressure sensitive and sends a signal ack to the computer when it touched by a plastic stick called a stylus. This is often used with handwriting recognition software to allow the user to enter data. The software is “taught” the shapes of letter that the user uses and then as the user writes on the touch screen the shapes are interpretted into text. Scanners: Used to input what is on paper (hardcopy) into the computer. This includes pictures, photographs and text. Text can be recognised by Optical Character Recognition (OCR) software that examines a scanned image for letters and other characters that it recognises and then converts it into a document that you can edit.| Microphone: Used to input sound. It can be used along with voice recognition software to enter text. The software is “trained” to recognise the way a user speaks and then converts the sounds into text. When using a microphone the computer needs to fitted with a sound card. This contains a processor and RAM used specifically for converting analogue sound to digital and for improving the quality of audio output. Digital Cameras
Digital cameras are used in just the same way as ordinary film cameras with the exception that the user can look at pictures that have been taken and delete the pictures they not like. Digital Video Camera are commonly used to record video clips.
It is very basic digital video cameras used to capture images to be sent down networks for video conferencing. Webcams do not allow you to save the images like digital video cameras do. Video conferencing is where people can “meet” across a network using microphones, webcams and monitors. This lets people meet who are different countries meet.
Printers: Printers are used to produce a hardcopy or printout of computer output. There are two kinds of printer you need to know about; inkjet printers and laser printers. | Inkjet printers have several advantages: * They produce high quality printouts of text and graphics. * They can print photographs. * They are usually cheaper to buy than laser printers. Laser printers also have several advantages: * They print several copies of something in less time than an inkjet printer. * The running costs of a laser printer are usually lower than for that of an inkjet printer. Plotters: A plotter produces hardcopy output like a printer but in a different way. It has one or more pens that draw onto the paper. Plotters are usually used for producing very accurate plans and drawings that have been created using Computer Aided Design.Monitors: These are sometimes called VDUs (Visual Display Units) and are the most commonly used output device. When you buy a computer you will usually get an LCD monitor.
LCD stands for Liquid Crystal Display. This is a flat screen that several advantages over the older CRT monitors. These advantages include: * They are much lighter and smaller than CRT monitors so they can be carried around easily and do not take up as much room on a desk. * They use much less electricity than a CRT monitor.For these reasons LCD screens are built into laptop and palmtop computers. One type of LCD monitor that is of a better quality is a TFT (Thin Film Transister) monitor. Loudspeakers: Used to output audio. Most computers come with speakers,either built in or as separate components.| | For computers to be able to output video and sound they need to have a sound card and a graphics card built into them. Sound cards convert digital data into analogue sounds that are outputted through the computers speakers. Complicated video files and graphics from computer games require a large amount of RAM and processing power. A graphics card comes with its own processor and RAM that are dedicated to the task of displaying these types of data, leaving the computers processor and RAM free for other tasks.