What is Classification of Computers
Computers are available in different sizes, shapes, and weights. Due to these different sizes and shapes, they perform different sort of jobs from one another. They can be classified in different ways. All the computers are designed by qualified computer architects who design these machines as per different requirements. A computer that is used in a home differs in size and shape from the computer being used in a hospital. Following sections are going to describe different classifications of computers. The term
"capacity" refers to the volume of work or the data processing capacity a computer can handle. Their performance is judged by the:
1. Amount of data that can be stored in memory
2. Speed of internal operation of the computer
3. Number and type of peripheral devices
4. Amount and type of software available for use with the computer
The capacity of early generation computers were determined by their physical size- the large the size, the greater the volume. In computer terms, size and speed of operation are at present proportionate to each other. Generally, though, recent, technology is tending to create smaller machines, making it possible to package equivalent speed and capacity in a smaller format.
Microcomputers: The mass production of silicon chips since 1971 has made it possible to put a "brain" into all sorts of machines. One such machine is the microcomputer. This machine has taken fullest advantage of the use of large-scale integration on silicon chips. The microprocessors literally contain a computer on a chip that can pass through the eye of needle. Microcomputers memories are generally made of semiconductors fabricated on silicon‟s chips. It is a digital computer system under the control of a stored program that uses a microprocessor, a programmable read-only memory (ROM), and a random-access memory (RAM). The ROM defines the instructions to be executed by the computer while RAM is the functional equivalent of computer memory. Today microcomputers are called as Personal Computers more commonly as PCs. These are small, relatively inexpensive computers designed for personal use in home or offices.
Minicomputers: Technological advances in the 1960's enabled manufactures to respond to the growing demand for a similar stand-alone machine, the minicomputer, to handle task that large computers could not perform economically. Minicomputer systems (or small mainframe computers) provide faster operating speeds and larger storage capacities than microcomputers systems. These Computers can support a large number of high-speed input/output devices. Several desk drives can be used to provide online access to large data files as required for direct - access processing. Operating system developed for minicomputer systems generally support both multiprogramming and virtual storage. This means that many programs can be run concurrently. This type of computer system is very flexible and can be improvised to meet the needs of users. Although the minicomputer is not as powerful as the medium or large-size computer, it is quite close.
Medium-size Computers : It provides faster operating speeds and larger storage capabilities than small computer systems. These Computers can support a large number of high-speed input-output devices, and several disk drives can be used to provide online access processing. The possibility of increasing the data processing capability of a computer by adding devices, such additional memory, and other peripheral devices, is called expandability.
Large Computers : These Computers are the ultimate in flexibility and speed. These usually contain full control systems with minimal operator intervention. Large computer systems range from single-processing configurations to nationwide computer based networks involving general large computers. Large computers have internal operating speeds measured in terms of nanoseconds, as a compared to smaller computers where speed in terms of microseconds.
Mainframe Computers : Mainframes are huge, multi-user systems designed to process millions of instructions per second and capable of accessing billions of data. They can handle gigantic processing jobs in large corporations or government agencies. This computer is commonly used in big hospitals, air line reservations companies and many other huge companies prefer mainframe because of its capability of retrieving data on huge basis. Mainframe allows its user to maintain large information storage at a centralized location and be able to access and process this data from different computers located at different locations.
Mainframe computers are normally too expensive and out of reach from a salaried person who wants this computer for his home. Mainframe is the second largest in capability and size of computer family.
Supercomputers : The most expensive in price, biggest and fastest machines today are the supercomputers that are used when billions or even trillions of calculations are needed. Supercomputers are ultra fast computers designed to process huge amounts of scientific data then display the underlying patterns that have been discovered. These machines are essential for applications ranging from nuclear weapon to accurate weather forecasting. Super Computers are used for highly calculation-intensive tasks such as molecular modeling, climate research, weather forecasting, quantum physics, physical simulations etc.
Supercomputers are machines that have speed in the 100-million-instructions-per-second range. Governments specially use this type of computer for their different calculations and heavy duty. Different industries also use this huge computer for designing their products. It is also used for animation purpose. The PARAM supercomputer is one of the supercomputer developed by India‟s Center for Development of Advanced Computing(C-DAC) and promises processing speeds of up to 1 trillions instructions per second. Since October 2010, the Tianhe-1A supercomputer is considered as the fastest supercomputer in the world which is located in China. Some of the examples of Supercomputer are: IBM Blue Gene/L, IBM Roadrunner, Cray Jaguar etc.
Classification by Technology
There are essentially two different types of computer processing. Each is made possible by a different kind of circuitry, and each is suitable for different purposes.
Analog Computers: The name analog comes from the word "analogous", meaning similar. Analog signal is a continuous signal whose amplitude can take any value in a continuous range. It can have infinite number of values. Analog computers deal with quantities that are continuously variable. They give only approximate results. These types of computer provide an analog or simulation of the object or system it represents. It is especially useful for solving problems that involve relationships between variable quantities in systems that change with time. The analog compute may express changing relationships in output in the form of graphs. It is able to create such pictures because it responds to changes in electrical voltages that match changes in variable quantities.
Figure: Analog Signal
Digital Computers : It is a machine that specializes in counting. It operates by counting values that are discrete, or separate and distinct, unlike the continuous quantities that can be measured by the analog computer. Digital signal is a discrete time signal that has a discrete number of levels. It can only assume one of the two values 0 or 1. While analog technology uses continuous signals, digital technology encodes the information into discrete signal states. Digital Computers are used for both business data processing and accuracy. The basic operation performed by a digital computer is addition. It can store the sums of addition problems as they accumulate, and can complete a single calculation in a fraction of a nanosecond. The digital computer is capable of storing data as long as needed, performing logical operations, editing input data, and printing out the results of its processing at high speed. Advantages of digital systems include flexible processing, easy to design, accuracy and precision, simple operation, easy data storage, less prone to noises etc.
Figure: Digital Signal
Hybrid Computers: Although both analog and digital computers are extremely used and widely accepted in various industries, manufacturers have to attempt to design a computer that combines the best features of both types. This special-purpose machine called a hybrid computer which combines the measuring capabilities of the analog computer and the logical and control capabilities of the digital computer. It offers an efficient and economical method of working out special types of problems in science and various areas of engineering. Some Hybrid machines contain special equipment to convert analog voltages into digital voltages, and vice-versa.
Check Your Progress 2
1) Distinguish between Microcomputer and Mainframe computer.
Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Its CPU is a microprocessor. The first microcomputers were built of 8-bit microprocessor chips. The most common application of personal computers (PC) is in this category. The PC supports a number of input and output devices. An improvement of 8-bit chip is 16-bit and 32-bit chips. Examples of microcomputer are IBM PC, PC-AT.
Mainframes computers are generally 32-bit microprocessors. They operate at very high speed, have very large storage capacity and can handle the work load of many users. They are generally used in centralized databases. They are also used as controlling nodes in Wide Area Networks (WAN). Example of mainframes are DEC, ICL and IBM 3000 series.
2) What are the five basic operations performed by the computer?
The five basic operations that a computer performs are accepting data as input, storage of these data, processing of data, outputting the information and process control.
3) How can you classify computers according to technology?
As per technology variations computers can be classified into analog, digital and hybrid computers.
WHAT IS INTEGRATED CIRCUIT
Our world is full of integrated circuits (semiconductor devices with several transistors built into one physical component). It is an electronic circuit which involves thousands or millions of interconnected components like transistors, diodes and resistors. They are usually called ICs. We can find several of them in computers. For example, most people have probably heard about the microprocessor. The microprocessor is an integrated circuit that processes all information in the computer.
Figure: Chip
It keeps track of what keys are pressed and if the mouse has been moved. It counts numbers and runs programs, games and the operating system. The first integrated circuits (ICs) were based on small scale integration (SSI) circuits, which had around 10 devices per circuit (or „chip‟), and evolved to the use of medium-scale integrated (MSI) circuits, which had up to 100 devices per chip. Integrated circuits are also found in almost every modern electrical device such as cars, television sets, CD players, cellular phones, etc. The main benefits of ICs are lower costs, high reliability and smaller space requirements. But what is an integrated circuit and what is the history behind it?
Electronic Circuits
The integrated circuit is nothing more than a very advanced electric circuit. An electric circuit is made from different electrical components such as transistors, resistors, capacitors and diodes, which are connected to each other in different ways. It is an unbroken loop of conductive material that allows electrons to flow continuously. If a circuit is "broken", its conductive elements will no longer form a complete path and continuous electron flow cannot occur. The transistor acts like a switch. It can turn electricity on or off, or it can amplify current. It is used for example in computers to store information.
The resistor limits the flow of electricity and gives us the possibility to control the amount of current that is allowed to pass. For example resistors are used, among other things, to control the volume in television sets or radios.
The capacitor collects electricity and releases it all in one quick burst. The diode stops electricity under some conditions and allows it to pass only when these conditions change. This is used in, for example, photocells where a light beam that is broken triggers the diode to stop electricity from flowing through it.
The flashlight is an example of electric circuits. It contains electrical energy (dry cells) as a source, a load (the bulb) which changes the electrical energy into light and a switch to control the energy delivered to the load.
The Transistor vs. the Vacuum Tube
The transistor is the most important one for the development of modern computers. Before the transistor, engineers had to use vacuum tubes. Just as the transistor, the vacuum tube can switch electricity on or off, or amplify a current. So why was the vacuum tube replaced by the transistor? There are several reasons.The vacuum tube looks and behaves very much like a light bulb; it generates a lot of heat and has a tendency to burn out. Also, compared to the transistor it is slow, big and bulky. When engineers tried to build complex circuits using the vacuum tube, they quickly became aware of its limitations. The first digital computer ENIAC, for example, was a huge monster that weighed over thirty tons, and consumed 200 kilowatts of electrical power. It had around 18,000 vacuum tubes that constantly burned out, making it very unreliable. When the transistor was invented in 1947 it was considered a revolution. Small, fast, reliable and effective, it quickly replaced the vacuum tube.
OPERATING SYSTEM
All computers need some sort of hardware platform to run the software; these platforms are called Operating System (OS). Operating system is a program that acts as an interface between user of computer and the computer hardware. The purpose of an operating system is to provide an environment in which user can execute program in a convenient and efficient manner. Operating system is an important part of almost every computer system. It manages all resources of computer system. Operating system is installed in secondary memory, while it‟s some part are stored permanently in read only memory.
Some part of the operating system resides in random access memory and the computer begins to execute this part of the system.
The majority of modern home computers use some form of Microsoft's operating systems. The original Microsoft operating system was called DOS (Disk Operating System) though most computers use Windows. Windows comes in various versions beginning with version 3.x then 95, 98, XP and currently Windows 7. A few computers use IBM's O/S2. Apple's Mac use their own operating system beginning with OS 1 though most modern Macs use version 8.x or 9.x. Apple's latest version is OS 10.1.x. Some computer professionals, Internet Service Providers (ISP) and mainframe computer users use an operating system such as UNIX, Windows NT or 2000 or server based operating systems. The operating system controls the input and output or directs the flow of information to and from the CPU. Much of this is done automatically by the system. In short, we can say that an Operating System is one of the most important components of the computer software which is essential to operate a computer. When computer is turned on, it first needs to load the operating system sometimes referred to a booting up. It checks all its components and will usually display a message if there is a problem. It is also known as Power on Self Test (POST). Loading the system is usually automatic. Once the system is loaded, the user can start the application or program that he/she going to use.
What is CURRENT APPLICATIONS OF COMPUTER
Some major applications of Computers are given below :
Banking : When there was no computer, every where manual system was followed which was a very complicated and hard work but now with the arrival of computer, every thing has become much more systematic and easy to use. Every bank is now using a computerized system because it is very fast and user friendly. Personal Computer banking lets us view our bank balance, request transfers between accounts and pay bills electronically. Now-a-days, online banking is getting very popular which offers more convenience and ease to the customers.
Traffic Light Control : In traffic light control, the computer is being employed to orchestrate the traffic light. There are some programmed codes like turn off/on the red light which control the traffic light and also to carry out other instructions.
Sports : Computers have revolutionized the sports industry. Computer is used to maintain player records, track scores, create virtual playing field etc. The sports equipment industry also relies heavily on computer-aided design (CAD).In sports, computers are used in conjunction with video cameras. These are used to record the motion of all the sports men. 3D programs are used to help the trainers see their movements and could improve their styles of playing. Online games allow us to play with other people regardless of their physical locations.
Schools and Colleges : There are many uses of computer in schools and colleges e.g. every students details need to be stored so a computer program comes to help in. Multimedia, animations, graphics and charts could be used to teach the students and many boring topics can be made interesting using multimedia. Students could access internet for online help and courses for more information. Computers are used in a variety of ways in the educational field. Computers can be used in school management such as budget, inventory, student records, communications, library circulation, and library public access catalog.
Learning and Instruction : Computer applications can be used in education for learning and for instruction. Instruction and learning can be divided into two major areas, teacher-centered instruction and student-centered learning. Teacher-centered instruction examined the computer as the object of instruction as well as a tool of instruction and the management of instruction. With the advancement in the Technology and Internet, Online Education, e-learning, m-learning are getting very popular which offers more flexibility and convenience to the learners.
Student-centered learning views the computer as a tool for the student to use and create access, retrieve, manipulate, and transmit information in order to solve a problem. Understanding the concept of the computer as an information tool relies on accepting the fact that the computer is a productivity tool for the student and the teacher alike.
Educational Research : Computers are used widely in all educational research. Educational research includes functions relating to information gathering and processing. The teacher/researcher may examine student performance data in new and revealing ways. Bibliographic citations of studies performed by educators around the world can be acquired and perused by the desktop computer.
Entertainment : Computers and Internet are a major source of entertainment. It is one of the latest forms of entertainment for the modern society. It allows us to play computer games, listen to music, watch videos and movies etc.
Health Care Management and Hospital : Today almost every hospital is computerized and utilizing the benefits of computer. Many computer applications, such as patient information system, monitoring and control system and diagnostic systems have been used to enhance health care. Hospital Information System (HIS) allows to manage the administrative, financial and clinical aspects of a Hospital more easily. It also allows easy access to patient data from a centralized database which helps the doctor in retrieving the history of all the patients. Computers are also being used in medical diagnosis and surgery.
Some of the other applications include Transport Management, Weather forecasting, Industries etc.
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