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WHAT IS A Computer - Mr. Anon Kit
Science, Technology and Society (GEC103)
Cagayan State University
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WHAT IS A COMPUTER?
A computer is an electronic device that manipulates information, or data. It has the ability to store, retrieve, and process data. You may already know that you can use a computer to type documents, send email, play games, and browse the Web.
Classification of Computers by Generation
- First-generation computers were based on vacuum tubes. These machines were large in size, expensive to operate and instructions were written in machine language. Their computation time was in milliseconds.
- Second-generation computers were based on transistors. They were smaller in size, less expensive and required less maintenance than the first-generation computers. They used the stored program concept. Programs were written in assembly language. The computation time was in microseconds.
- Third-generation computers were characterized by the use of Integrated Circuits. They consumed less power and required low maintenance compared to their predecessors. High-level languages were used for programming. The computation time was in nanoseconds. These computers marked the beginning of commercial production.
- Fourth-generation computers used microprocessors which were designed using the LSI (Large Scale Integration) and VLSI (Very Large-Scale Integration) technology. The computers became small, portable, reliable and cheap. The computation time is in picoseconds. They became available both to the home user and for commercial use.
- Fifth-generation computers are expected to be capable of learning and self- organization. The computers use SLSI (Super Large-Scale Integration) chips and have large memory requirements. They use parallel processing and are based on (AI) Artificial Intelligence. The fifth-generation computers are still being developed.
Classification of computers by Types
Analog Computers:
An analog computer is a kind of computer that represents data as a variable across a continuous range of values. The earliest computers were analog computers. Analog computers are used for measuring parameters that vary continuously in real-time, such as temperature, pressure, and voltage. Analog computers may be more flexible but generally less precise than digital computers. The slide rule is an example of an analog computer. In general, analog computers are extraordinarily fast, since they can solve most complex equations at the rate at which a signal traverses the circuit, which is generally an appreciable fraction of the speed of light. On the other hand, the precision of analog computers is not good; they are limited to three, or at most, four digits of precision.
Digital Computer:
A digital computer uses distinct values to represent the data internally. All information is represented using the digits 0s and 1s. The computers that we use in our homes and offices are digital computers. Digital computers can be built to take the solution of equations to almost unlimited precision, but quite slowly compared to analog computers. Generally, complex equations are approximated using iterative numerical methods which take huge numbers of iterations, depending on how good the initial “guess” at the final value is and how much precision is desired.
Hybrid Computer:
Hybrid computers are computers that exhibit features of analog computers and digital computers. The digital component normally serves as the controller and provides logical operations, while the analog component normally serves as a solver of differential equations. Hybrid computers can be used to obtain a very good but relatively imprecise ‘seed’ value, using an analog computer front-end, which is then fed into a digital computer iterative process to achieve the final desired degree of precision. With a three or four-digit, highly accurate numerical seed, the total digital computation time necessary to reach the desired precision is dramatically reduced, since many fewer iterations are required.
Classification of computers by Size
Microcomputers:
Microcomputers are relatively small and low-cost. They consist of a CPU, an input unit, an output unit, a storage unit, and the software. Although microcomputers are stand- alone machines, they can be connected together to create a network of computers that can serve more than one user. Microcomputers include desktop computers, notebook computers or laptops, tablet computers, handheld computers, smartphones, and netbooks, as shown in the figure below.
The Desktop Computer usually called Personal Computer (PC) is the most common type of microcomputer. It is a standalone machine that can be placed on the desk. Notebook Computers or Laptops look like a notebook. They are portable and have all the features of a desktop computer. The advantage of the laptop is that it is small in size, can be carried anywhere, has a battery backup, and has all the functionality of the desktop. Laptops can be placed on the lap while working (hence the name). However, some laptops are costlier than desktop machines, depending on system configurations.
require frequent access to the same data. Some examples of mainframes are CDC 6600 and IBM ES000 series. The figures below are examples of mainframe computers.
Supercomputers:
Supercomputers are the fastest and most expensive machines. They have high processing speed compared to other computers. The speed of a supercomputer is generally measured in FLOPS (Floating Point Operations Per Second). Some of the faster supercomputers can perform trillions of calculations per second. Supercomputers are built by interconnecting thousands of processors that can work in parallel.
Supercomputers are used for highly calculation-intensive tasks, such as weather forecasting, climate research (global warming), molecular research, biological research, nuclear research, and aircraft design. They are also used in major universities, military agencies, and scientific research laboratories. Some examples of supercomputers are IBM Roadrunner, IBM Blue Gene, and Intel ASCI red. PARAM is a series of supercomputers assembled in India by C-DAC (Center for Development of Advanced Computing), in Pune. PARAM Padma is the latest machine in this series. The peak computing power of PARAM Padma is 1 TeraFLOP (TFLOP). The diagrams below are examples of supercomputers.
Classification of Computers by Degree of Versatility
General-Purpose Computers:
General-purpose computers are designed to solve a large variety of problems. That is they can be given different programs to solve different types of problems. General- purpose computers can process business data as readily as they process complex mathematical formulas. General-purpose computers can store a large amount of data and the programs necessary to process them. Because general-purpose computers are so versatile, most businesses today use them. Most digital computers are general computers and it is mainly such computers that are used in business and commercial data processing. A PC or a Mac and other types of computers can do a huge amount of things. They can be used by different people for completely different kinds of jobs. They are general-purpose computers.
Special-Purpose Computers:
Special purpose computers are designed to solve specific problems; the computer program for solving the problem is built right into the computer. Special purpose computers have many features of general-purpose computers but are designed to
handle specific problems and are not applied to other computerized activities. For example, special purpose computers may be designed to process only numeric data or to completely control automated manufacturing processes. Moat analog computers are special-purpose computers. Special purpose computers are designed to do specific kinds of jobs. A TV, a washing machine, an iPod etc, are forms of computers, but they have only a small range of things that they can do, and are designed specifically to do them.
Special purpose computers are often used as training simulators. A simulator is a computer-controlled device for training people under simulated, or artificially created, conditions. The computer creates test conditions the trainee must respond to, it then records and evaluates the responses, providing these results to both trainee and supervisor.
Components of Computer System
There are three major components of a computer system, namely: hardware, software, and peopleware.
Hardware components
These include the physical components that make up a computer system. The hardware components include all components that a user can see and touch while using the computer. A computer system consists of four basic units; namely the input unit, a storage unit, a central processing unit, and an output unit. The central processing unit is further divided into Arithmetic logic unit and control unit. These four units enable the computer to perform the following five basic functions:
Accepts data or instructions as input
Stores data and instructions
Processes data based on per-user instructions
Controls all operations inside a computer
Gives results in the form of output to the user.
Input devices: Input devices are used to enter data into the computer system. The hardware components that make up the input unit include a mouse, keyboard, scanner, touchscreen monitor, camera/camcorder, joystick, and microphone.
Software components
Software components of a computer system have no physical presence but are a set of instructions and data stored in digital form within the computer memory. They have basically divided into two: system software and application software.
The system software is used to manage and control the hardware components of the computer. It allows for user interaction between the hardware and application software. There are two major categories of system software: the operating system and device drivers.
An application software otherwise called ‘apps’ are designed to allow users of a computer system to complete specific tasks. The application software is the major purpose for which we buy and learn how to use the computer system.
Application software can either be generic or bespoke. Generic application software is usually mass-produced with the intention that it will be used by a wide variety of different users in a wide range of different situations. This makes their cost cheaper and availability rampart. The bespoke or custom-built software is created for a specific purpose which will be used in a known environment. This makes them more expensive and very rare to see.
Another type of software is utility software. It helps a user to maintain and protect the computer system but does not directly interface with the computer hardware. Examples are anti-virus software, firewalls, disk defragmenters, disk cleanup, etc.
People-ware components
The computer is designed to be used by people. The people who use the computer are referred to as peopleware component of the computer system. Peopleware refers to the role of people in the development and use of computer software and hardware.
Anyone who designs, develops or uses computer systems plays an important role in the computing process. They include computer professionals and users such as computer engineers, programmers, individual computer users, software engineers, IT specialists, network engineers, graphic designers, computer technicians, database administrators, desktop publishers, etc.
The relationship between hardware, software, and people-ware
The hardware, software, and peopleware are indispensable. All of them complement one another and none can function without the other. For example, people created both the software and the hardware, and the hardware cannot function without the software, neither will the software function without the hardware. Also, both the hardware and software need people to operate them for them to function.
One hardware can be used to load different software depending on who is using it. This means that people (users) determine the kind of software that can be loaded (installed) in a computer hardware.
The kind of job people does determine the kind of hardware and software that they can use. For example, the kind of computer hardware and software a film editor uses is different from the kind desktop publisher uses.
Hardware is mostly purchased once while software used in computer hardware changes over time. Similarly, one or more persons can use computer hardware and software over time.
Hardware, software, and peopleware can be upgraded over time. This means that obsolete and less functional hardware can be changed or upgraded for more efficiency, while over time, the software is updated to accommodate recent development in information and communication trends. Also, computer professionals and users upgrade their knowledge of innovative developments in hardware and software industry to maximize productivity and usability.
Definition of Software
A computer software can be visualized as the intangible component of the computer system. It is the collection of programs, instructions, and data that directs the computer to perform specific tasks.
System Software
The system software is the backbone of the computer system. It has various functions including, controlling, integrating and managing the computer hardware components. It also interfaces between the user, application software and hardware such that users of the system see it as a functional unit. System software can be classified as the operating system, drivers, and utilities.
Operating system:
Examples of the operating system include Unix, Linux, Mac Os, OS/2, Xenix, Windows NT, Windows XP, Windows 7, Windows 8, HP-UX, Android (for mobile devices), etc.
Drivers:
Device drivers are operating system specific. A driver that works in Windows 7 may not necessarily work in windows 8. Examples of device drivers: printer drivers, video adapter drivers, network drivers, sound card drivers, etc.
Utility software:
- Linux – usually available as commercial and Open Source software. There are different Linux OS depending on the distribution: Red Hat, Ubuntu, OpenSuse, Fedora, LinuxMint, Debian, etc.
- Macintosh – usually called Mac, was introduced by Apple computer.
- Windows – which is the most popular OS used today, especially in Nigeria. Windows OS is developed by Microsoft Inc. it has various versions including Windows 95, 98, Me, NT, XP, Vista, 7, 8, 8, etc.
Functions of Operating System
The basic functions of an operating system are:
- It helps in booting the computer system
- It monitors the system performance and activities
- It helps in managing various peripheral devices such as mouse, keyboard, printer, etc
- It provides a user interface for effective operating of the computer, e. command line and graphical user interface (GUI)
- It helps in resource allocation such as computer’s memory and sharing of the central processing unit time by various applications or peripheral devices
- It provides a system of file management which includes the way the operating system manipulates, stores, retrieves and saves data.
- It assists in computer utility functions such as backup and restores operations, defragmentation, disk cleaning, etc.
WHAT IS A Computer - Mr. Anon Kit
Course: Science, Technology and Society (GEC103)
University: Cagayan State University
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