Computer
A computer system consists of mainly four basic units; namely input unit, storage unit, central processing unit and output unit. Central Processing unit further includes Arithmetic logic unit and control unit.
A computer performs five major operations or functions irrespective of its size and make. These are
- It accepts data or instructions as input,
- It stores data and instruction
- It processes data as per the instructions,
- It controls all operations inside a computer, and
- It gives results in the form of output.
Modern Computers Defined
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.
All general-purpose computers require the following hardware components:
- Memory: enables a computer to store, at least temporarily, data and programs.
- Mass storage device: allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.
- Input device: usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.
- Output device: a display screen, printer, or other device that lets you see what the computer has accomplished.
- Central processing unit (CPU): the heart of the computer, this is the component that actually executes instructions.
In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.
Computer Classification, By Size and Power
Computers can be generally classified by size and power as follows, though there is considerable overlap:
- Personal computer: a small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
- Workstation: a powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.
- Minicomputer: a multi-user computer capable of supporting from 10 to hundreds of users simultaneously.
- Mainframe: a powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.
- Supercomputer: an extremely fast computer that can perform hundreds of millions of instructions per second.
Types of Computers
Computers can be classified based on their principles of operation or on their configuration. By configuration, we mean the size, speed of doing computation and storage capacity of a computer.
Types of Computers based on Principles of Operation
1. Analog Computers
Analog Computer is a computing device that works on continuous range of values. The results given by the analog computers will only be approximate since they deal with quantities that vary continuously. It generally deals with physical variables such as voltage, pressure, temperature, speed, etc.
2. Digital Computers
On the other hand a digital computer operates on digital data such as numbers. It uses binary number system in which there are only two digits 0 and 1. Each one is called a bit. The digital computer is designed using digital circuits in which there are two levels for an input or output signal. These two levels are known as logic 0 and logic 1. Digital Computers can give more accurate and faster results. Digital computer is well suited for solving complex problems in engineering and technology. Hence digital computers have an increasing use in the field of design, research and data processing. Based on the purpose, Digital computers can be further classified as,
- General Purpose Computers
- Special Purpose Computers
Special purpose computer is one that is built for a specific application. General purpose computers are used for any type of applications. They can store different programs and do the jobs as per the instructions specified on those programs. Most of the computers that we see today are general purpose computers.
3. Hybrid Computers
A hybrid computer combines the desirable features of analog and digital computers. It is mostly used for automatic operations of complicated physical processes and machines. Now-a-days analog-to-digital and digital-to-analog converters are used for transforming the data into suitable form for either type of computation. For example, in hospital’s ICU, analog devices might measure the patients’ temperature, blood pressure and other vital signs. These measurements which are in analog might then be converted into numbers and supplied to digital components in the system. These components are used to monitor the patient’s vital sign and send signals if any abnormal readings are detected. Hybrid computers are mainly used for specialized tasks.
Functional Units of computer
- Input Unit: This unit is used for entering data and programs into the computer system by the user for processing. This is supposed to be a flash animation. You'll need the flash plug-in and a browser that supports it to view it.
- Storage Unit: The storage unit is used for storing data and instructions before and after processing.
- Output Unit: The output unit is used for storing the result as output produced by the computer after processing.
- Processing: The task of performing operations like arithmetic and logical operations is called processing. The Central Processing Unit (CPU) takes data and instructions from the storage unit and makes all sorts of calculations based on the instructions given and the type of data provided. It is then sent back to the storage unit. CPU includes Arithmetic logic unit (ALU) and control unit (CU)
- Arithmetic Logic Unit: All calculations and comparisons, based on the instructions provided, are carried out within the ALU. It performs arithmetic functions like addition, subtraction, multiplication, division and also logical operations like greater than, less than and equal to etc.
- Control Unit: Controlling of all operations like input, processing and output are performed by control unit. It takes care of step-by-step processing of all operations inside the computer.
Uses of Computer
- Education: Getting the right kind of information is a major challenge as is getting information to make sense. College students spend an average of 5-6 hours a week on the internet. Research shows that computers can significantly enhance performance in learning. Students exposed to the internet say they think the web has helped them improve the quality of their academic research and of their written work. One revolution in education is the advent of distance learning. This offers a variety of internet and video-based online courses.
- Health and Medicine: Computer technology is radically changing the tools of medicine. All medical information can now be digitized. Software is now able to computer the risk of a disease. Mental health researchers are using computers to screen troubled teenagers in need of psychotherapy. A patient paralyzed by a stroke has received an implant that allows communication between his brain and a computer; as a result, he can move a cursor across a screen by brainpower and convey simple messages.
- Science: Scientists have long been users of it. A new adventure among scientists is the idea of a “Collaboratory”, an internet based collaborative laboratory, in which researchers all over the world can work easily together even at a distance. An example is space physics where space physicists are allowed to band together to measure the earth’s ionosphere from instruments on four parts of the world.
- Business: Business clearly sees the interest as a way to enhance productivity and competitiveness. Some areas of business that are undergoing rapid changes are sales and marketing, retailing, banking, stock trading, etc. Sales representatives not only need to be better educated and more knowledgeable about their customer’s businesses, but also must be comfortable with computer technology. The internet has become a popular marketing tool. The world of cyber cash has come to banking – not only smart cards but internet banking, electronic deposit, bill paying, online stock and bond trading, etc.
- Recreation and Entertainment: Our entertainment and pleasure-time have also been affected by computerization. For example:
- In movies, computer generated graphics give freedom to designers so that special effects and even imaginary characters can play a part in making movies, videos, and commercials.
- In sports, computers compile statistics, sell tickets, create training programs and diets for athletes, and suggest game plan strategies based on the competitor’s past performance.
- In restaurants, almost everyone has eaten food where the clerk enters an order by indicating choices on a rather unusual looking cash register; the device directly enters the actual data into a computer, and calculates the cost and then prints a receipt.
- Government: Various departments of the Government use computer for their planning, control and law enforcement activities. To name a few – Traffic, Tourism, Information & Broadcasting, Education, Aviation and many others.
- Defense: There are many uses computers in Defense such as:
- Controlling UAV or unmanned air-crafts an example is Predator. If you have cable, I would recommend watching the shows “Future Weapons" and “Modern Marvels". The show future weapon gives an entire hour to the predator.
- They are also used on Intercontinental Ballistic Missiles (ICBMs) that uses GPS and Computers to help the missile get to the target.
- Computers are used to track incoming missiles and help slew weapons systems onto the incoming target to destroy them.
- Computers are used in helping the military find out where all their assets are (Situational Awareness) and in Communications/Battle Management Systems.
- Computers are used in the logistic and ordering functions of getting equipments to and around the battlefield.
- Computers are used in tanks and planes and ships to target enemy forces, help run the platform and more recently to help diagnose any problems with the platforms.
- Computers help design and test new systems.
- Sports: In today's technologically growing society, computers are being used in nearly every activity.
- Recording Information - Official statistics keepers and some scouts use computers to record statistics, take notes and chat online while attending and working at a sports event.
- Analyzing Movements - The best athletes pay close attention to detail. Computers can slow recorded video and allow people to study their specific movements to try to improve their tendencies and repair poor habits.
- Writers - Many sportswriters attend several sporting events a week, and they take their computers with them to write during the game or shortly after while their thoughts are fresh in their mind.
- Scoreboard - While some scoreboards are manually updated, most professional sports venues have very modern scoreboards that are programmed to update statistics and information immediately after the information is entered into the computer.
- Safety - Computers have aided in the design of safety equipment in sports such as football helmets to shoes to mouth guards.
What Are the Advantages of Computers in Business?
Computers have tremendously improved the way businesses operate in their respective industries. Technology has advanced so remarkably that those who are not using computers in their business are at a major disadvantage against their competitors. In particular, there are several important advantages that computers can provide to small businesses.
- Organization - Computers allow the application of different types of software that can help businesses keep track of their files, documents, schedules and deadlines. Computers also allow businesses to organize all of their information in a very accessible manner. The ability to store large amounts of data on a computer is convenient and inexpensive, and saves space. A computer's ability to allow a company to organize its files efficiently leads to better time management and productivity.
- Self-Sufficiency - Computers have made staff and companies more self-sufficient by allowing them to do tasks that previously had to be outsourced. For example, a company can now use office software to create their own training material. Desktop publishing software can be used to create marketing materials. Online tax and accounting programs allow companies to prepare their own taxes. This allows the dominant operations of a company to remain in-house and empowers the company to become more independent and less susceptible to errors committed by outside parties.
- Cost-Effective - Emerging technology makes new tools and services more affordable and allows companies to save on their staff payroll and office equipment. Because computers allow work to be done faster and more efficiently, it is possible for a company to hire fewer staff. In addition, with networked and relatively inexpensive computers, companies can store data more easily, saving on the cost of outside file storage, and can avoid having to purchase as many copiers, fax machines, typewriters, and other such items that were used before computers became popular. Correspondingly, potentially profitable businesses can be started with a smaller overhead cost. Email capabilities decrease postage costs; software applications reduce the need for large accounting departments, while videoconferencing reduces the need for travel. All resources saved will trickle down to the consumers, who are then provided with much more affordable products and service.
- Speed - Computers help speed up other business operations. The collecting of consumer feedback, ordering of raw materials, and inspection of products is made quicker through the use of computers, allowing companies to operate much faster and to produce better quality results.
- Cheaper Research and Development - R&D, or research and development, costs will also decrease with the help of computers. Scientific research can now be done using the Internet and computer software applications designed to develop and produce new products and services. For example, instead of a company having to do in-person focus groups on a potential new product or to determine their target market, the company can conduct a widespread online survey for a far lower cost. In addition, new models of a product can be created online using virtual pictures and drawings instead of having to be hand-drawn. These interactive models created using software programs can help bring the product and its features to life for a far lower cost than creating an actual physical model of the given product.
- Sales - Computers can help generate higher sales and profits for businesses via a company website. Many businesses now operate online and around the clock to allow customers from around the world to shop for their products and services.
Types of Computers based on Configuration
There are four different types of computers when we classify them based on their performance and capacity. The four types are
- Super Computers - When we talk about types of computers, the first type that comes to our mind would be Super computers. They are the best in terms of processing capacity and also the most expensive ones. These computers can process billions of instructions per second. Normally, they will be used for applications which require intensive numerical computations such as stock analysis, weather forecasting etc. Other uses of supercomputers are scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting). Perhaps the best known super computer manufacturer is Cray Research. Some of the "traditional" companies which produce super computers are Cray, IBM and Hewlett-Packard.
- Mainframe Computers - Mainframe computers can also process data at very high speeds vie. Hundreds of million instructions per second and they are also quite expensive. Normally, they are used in banking, airlines and railways etc for their applications.
- Mini Computers - Mini computers are lower to mainframe computers in terms of speed and storage capacity. They are also less expensive than mainframe computers. Some of the features of mainframes will not be available in mini computers. Hence, their performance also will be less than that of mainframes.
- Micro Computers - The invention of microprocessor (single chip CPU) gave birth to the much cheaper microcomputers. They are further classified into
- Desktop Computers - Today the Desktop computers are the most popular computer systems. These desktop computers are also known as personal computers or simply PCs. They are usually easier to use and more affordable. They are normally intended for individual users for their word processing and other small application requirements.
- Laptop Computers - Laptop computers are portable computers. They are lightweight computers with a thin screen. They are also called as notebook computers because of their small size. They can operate on batteries and hence are very popular with travellers. The screen folds down onto the keyboard when not in use.
- Handheld Computers (PDAs) - Handheld computers or Personal Digital Assistants (PDAs) are pen-based and also battery-powered. They are small and can be carried anywhere. They use a pen like stylus and accept handwritten input directly on the screen. They are not as powerful as desktops or laptops but they are used for scheduling appointments, storing addresses and playing games. They have touch screens which we use with a finger or a stylus.
FAQ’s
What is a computer?
A computer is a programmable machine. The two principal characteristics of a computer are: it responds to a specific set of instructions in a well-defined manner and it can execute a prerecorded list of instructions (a program).
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