The Part of a Computer System
My Future Profession
Computer industry is developing so fast, that it comprises almost all spheres of professional life. No business now is possible without computers. This is especially true about automated manufacturing of products and robotics. Computer control of automated production opens new horizons for the cheap and quality production of goods. Information is now generated, transmitted, received, and stored electronically through computer networks on a scale unprecedented in history, and there is every indication that the explosive rate of growth in this field will continue.
I was always good at mathematics and physics. That's why I decided to become a specialist in computer technologies - a computer engineer. Computer engineering is a general field. It deals with both electric and electronic industries.
Electronic engineering deals with the research, design, integration, and application of circuits and devices used in the transmission and processing of information.
Engineers work on control systems which are used extensively in automated manufacturing and in robotics.
Computer engineering is now the most rapidly growing field. The electronics of computers is the design and manufacture of memory systems, of central processing units, and of peripheral devices. The field of computer science is closely related to computer engineering.
One current trend in computer engineering is to work to fit greater and greater numbers of circuit elements onto smaller and smaller chips.
Another trend is towards increasing the speed of computer operations.
So, there are a lot of employment opportunities in my field. I don't worry about finding a job. The most important thing for me now is to study well and to graduate from the University.
OPTICAL TECHNOLOGY
One of the most interesting developments in telecommunication is the rapid progress of optical communication where optical fibers are replacing conventional telephone wires and cables. Just as digital technologies greatly improved the telephone system, optical communication promises a considerable increase in capacity, quality, performance and reliability of the global telecommunication network. New technologies such as optical fibers will increase the speed of telecommunication and provide new, specialized information service. Voice, computer data, even video images, will be increasingly integrated into a single digital communication network capable of processing and transmitting virtually any kind of information.
It is a result of combining two technologies: the laser, first demonstrated in 1960, and the fabrication 10 years later of ultra-thin silicon fibres which can serve as lightwave conductors. With the further development of very efficient lasers plus continually improved techniques to produce thin silica fibres of incredible transparency, optical systems can transmit pulses of light as far as 135 kilometers without the need for amplification or regeneration.
At present high-capacity optical transmission systems are being installed between many major US cities at a rapid rate. The system most widely used now operates at 147 megabits per second and accommodates 6,000 circuits over a single pair of glass fibres (one for each direction of transmission).
This system will soon be improved to operate at 1.7 gigabits per second and handle 24,000 telephone channels simultaneously. A revolution in information storage is underway with optical disk technology.
The first digital optical disks were produced in 1982 as compact disks for music. They were further developed as a storage medium for computers. The disks are made of plastics coated with aluminium. The information is recorded by using a powerful laser to imprint bubbles on the surface of the disk. A less powerful laser reads back the pictures, sound or information. An optical disk is almost indestructible and can store about 1000 times more information than a plastic disk of the same size.
One CD-ROM disk (650 MB) can replace 300,000 pages of text (about 500 floppies), which represents a lot of savings in databases. The future of optical storage is called DVD (digital versatile disk). A DVD-ROM can hold up to 17 GB, about 25 times an ordinary CD-ROM.
For this reason, it can store a large amount of multimedia software and complete full-screen Hollywood movies in different languages. However, DVD-ROMs are “read-only” devices. To avoid this limitation, companies also produce DVD rewritable drives.
Besides, it is reported that an optical equivalent of a transistor has been produced and intensive research on optical electronic computers is underway at a number of US companies as well as in countries around the world. It is found that optical technology is cost-effective and versatile.
It finds new applications every day - from connecting communication equipment or computers within the same building or room to long-distance transcontinental, transoceanic and space communications.
The Part of a Computer System
In order to use computers effectively to solve problems in our environment, computer systems are devised. Computer systems may be discussed in two parts.
The first part is hardware — the physical, electronic, and electromechanical devices that are thought of and recognized as "computers". The hardware consists of Central Processing Unit (CPU), input devices and output devices. The CPU is made up of a processor and a main memory, or main store. The processor carries out, or executes, instructions in the program. The main memory stores input data and the program needed by the processor. The main memory also holds output data, or the results of processing.
Input devices are used to provide data for the CPU. The keyboard is a common data input device. By using a keyboard, a user can enter data directly into the computer system. Data is sometimes entered on cards. The cards are read by an input device called a card reader. Data is often input from a mass storage device, such as magnetic tape or magnetic disc. A mass storage device has a much larger capacity than main memory. That is, it can store more data. The tapes or discs are read by an input device called a tape drive or a disc drive.
Output devices receive data from the CPU. The Visual Display Unit (VDU) and printer are common output devices. The VDU is similar to a television screen. The printer produces printed output on paper. Both the VDU and printer present output data for immediate use. Sometimes, the output data is transmitted along a telephone line to another computer. Output data can also be stored for future use on a mass storage device, such as magnetic tape or magnetic disc.
Input devices, output devices and mass storage devices are collectively called Input-Output Devices (I/O Devices), or peripherals.
The second part is software — the programs that control and coordinate the activities of the computer hardware and that direct the processing of data.
For the computer system to operate, computer programs are required. A computer program is a set of instructions for the CPU. These instructions tell the CPU where to find the input data in the system. The CPU is also instructed how to process the data and where to put the results. Programs are not hardware, as they have no electrical or mechanical components. They can be easily changed according to the needs of the user.
Computer software can be divided into two very broad categories — systems software and application software.
WINDOWS
Microsoft Windows (or simply Windows) is a software programme that makes your IBM PC (or compatible) easy to use. It does this by simplifying the computer's user interface.
The word “interface” refers to the way you give your computer commands, the way you interact with it. Usually the interface between you and the computer consists of the screen and the keyboard, you interact with the computer by responding to what's on the screen, typing in commands at the DOS command line to do your work.
DOS often isn't very intelligent at interpreting your commands and most people consider it awkward or intimidating as a user interface. These commands can be confusing and difficult to remember. Who wants to learn lots of computer commands just to see what's on your disk, copy a file, or format a disk?
Windows changes much of this. What's been missing from the PC is a programme that makes the computer easy to use. Windows is just such a programme. With Windows, you can run programmes, enter and move data around, and perform DOS-related tasks simply by using the mouse to point at objects on the screen. Of course, you also use the keyboard to type in letters and numbers. Windows interprets your actions and tells DOS and your computer what to do.
In addition to making DOS housekeeping tasks such as creating directories, copying files, deleting files, formatting disks, and so forth, easier, Windows makes running your favourite applications easier, too. (An application is a software package that you use for a specific task, such as word processing).
Windows owes its name to the fact that it runs each programme or document in its own separate window. (A window is a box or frame on the screen.) You can have numerous windows on the screen at a time, each containing its own programme and/or document. You can then easily switch between programmes without having to close one down and open the next.
Another feature is that Windows has a facility - called the Clipboard - that lets you copy material between dissimilar document types, making it easy to cut and paste information from, say, a spreadsheet into a company report or put a scanned photograph of a house into a real estate brochure.
In essence, Windows provides the means for seamlessly joining the capabilities of very different application programmes. Not only can you paste portions of one document into another, but by utilizing more advanced document-linking features those pasted elements remain “live”. That is, if the source document (such as some spreadsheet data) changes, the results will also be reflected in the secondary document containing the pasted data.
As more and more application programmes are written to run with Windows, it'll be easier for anyone to learn how to use new programmes. This is because all application programmes that run in Windows use similar commands and procedures.
Windows comes supplied with a few of its own handy programmes. There's a word-processing programme called Write, a drawing programme called Paintbrush, a communications programme called Terminal for connecting to outside information services over phone lines, small utility programmes that are helpful for keeping track of appointments and notes, a couple of games to help you escape from your work, and a few others.
Years of research went into developing the prototype of today's popular graphical user interfaces. It was shown in the early 1980s that the graphical user interface, in conjunction with a hand-held pointing device (now called the mouse), was much easier to operate and understand than the older-style keyboard-command approach to controlling a computer. A little-known fact is that this research was conducted by the Xerox Corporation and first resulted in the Xerox Star computer before IBM PCs or Macintoshes existed. It wasn't until later that the technology was adapted by Apple Computer for its Macintosh prototype, the Lisa.
PROGRAMMING LANGUAGES
The only language computers can understand directly is called machine code. It is known to consist of the 1s and 0s (binary code) that are processed by the CPU. However, machine code as a means of communication is very difficult to write. That is why it is necessary to use symbolic languages that are easier to understand. Then, by using a special programme, these languages can be translated into machine code.
Basic languages, in which the program is similar to the machine code version, are known as low-level languages. In these languages, each instruction is equivalent to a single machine code instruction, and the programme is converted into machine code by a special programme called an assembler. These languages are considered to be still quite complex and restricted to particular computers.
To make the programme easier to write and to overcome the problem of intercommunication between different types of machines, higher-level languages were developed such as BASIC, COBOL, FORTRAN, Pascal, Ada, С and others. A higher-level language is a problem oriented programming language, whereas a low-level language is machine oriented.
This means that a high-level language is a convenient and simple means of describing the information structures and sequences of actions to be performed for a particular task.
A high-level language is independent of the architecture of the computer which supports it. This has two advantages. Firstly, the person writing the program does not have to know anything about the computer the programme will be run on. Secondly, programmes are portable, that is, the same programme can (in theory) be run on different types of computers. Programmes written in one of these languages should be converted by means of a compiler into a lower-level language or machine code so that the CPU could understand it.
С, a high-level programming language, seems to be very popular today because it is small, so it is not too hard to learn, it is very efficient and portable so one can use it with all kinds of computers. A lot of software engineers use С to write commercial applications programmes for mini, micro and personal computers. There are also various versions of С — C++ and Objective C, which represent a new style of programming.
At present there is a tendency towards an even higher level of programming languages, which might be called specification languages, and an increasing use of software development tools.
People communicate instructions to the computer in symbolic languages and the easier this communication can be made, the wider the application of computers will be. Scientists are reported to be already working on Artificial Intelligence and the next generation of computers may be able to understand human languages.
COMPUTER GRAPHICS
Computer graphics are pictures and drawings produced by computers. A graphics programme interprets the input provided by the user and transports it into images that can be displayed on the screen, printed on paper or transferred to microfilm. In the process the computer uses hundreds of mathematical formulas to convert the bits of data into precise shapes and colours. Graphics can be developed for a variety of uses including illustrations, architectural designs and detailed engineering drawings.
Mechanical engineering uses sophisticated programs for applications in computer-aided design (CAD) and computer-aided manufacturing (CAM). In the car industry CAD software is used to develop, model and test car designs before the actual parts are made. This can save a lot of time and money.
Basically, computer helps users to understand complex information quickly by presenting it in more understandable and clearer visual forms. Electric engineers use computer graphics for designing circuits and in business it is possible to present information as graphics and diagrams.
These are certain to be much more effective ways of communicating than lists of figures or long explanations. Today, three-dimensional graphics along with colour and computer animation are supposed to be essential for graphic design, computer-aided engineering (CAE) and academic research. Computer animation is the process of creating objects and pictures which move across the screen; it is used by scientists and engineers to analyze problems. With appropriate software they can study the structure of objects and how it is affected by particular changes.
A graphic package is the software that enables the user to draw and manipulate objects on a computer. Each graphic package has its own facilities, as well as a wide range of basic drawing and painting tools.
The collection of tools in a package is known as a palette. The basic geometric shapes, such as lines between two points, arcs, circles, polygons, ellipses and even text, making graphical objects are called “primitives”. You can choose both the primitive you want and where it should go on the screen. Moreover, you can specify the “attributes” of each primitive, e.g., its colour, line type and so on. The various tools in a palette usually appear together as pop-up icons in a menu. To use one you can activate it by clicking on it.
After specifying the primitives and their attributes you must transform them. Transformation means moving or manipulating the object by translating, rotating and scaling the object.
Translation is moving an object along an axis to somewhere else in the viewing area. Rotation is turning the object larger or smaller in any of the horizontal, vertical or depth direction (corresponding to the x, у and z axis). The term “rendering” describes the techniques used to make your object look real. Rendering includes hidden surface removal, light sources and reflections.
THE INTERNET
The Internet is a magnificent global network with millions and millions of computers and people connected to one another where each day people worldwide exchange an immeasurable amount of information, electronic mail, news, resources and, more important, ideas.
It has grown at a surprising rate. Almost everyone has heard about it and an increasing number of people use it regularly. The current estimate is that over 70 million people are connected, in some way, to the Internet -whether they know it or not.
With a few touches at a keyboard a person can get access to materials in almost everywhere. One can have access to full-text newspapers, magazines, journals, reference works, and even books. The Web is one of the best resources for up-to-date information. It is a hypertext-based system by which you can navigate through the Internet. Hypertext is the text that contains links to other documents. A special program known as “browser” can help you find news, pictures, virtual museums, electronic magazines, etc. and print Web pages. You can also click on keywords or buttons that take you to other pages or other Web sites. This is possible because browsers understand hypertext markup language or code, a set of commands to indicate how a Web page is formatted and displayed.
Internet Video conferencing programmes enable users to talk to and see each other, exchange textual and graphical information, and collaborate. Internet TV sets allow you to surf the Web and have e-mail while you are watching TV, or vice versa. Imagine watching a film on TV and simultaneously accessing a Web site where you get information on the actors of the film. The next generation of Internet-enabled televisions will incorporate a smart-card for home shopping, banking and other interactive services. Internet-enabled TV means a TV set used as an Internet device.
The Internet is a good example of a wide area network (WAN). For long-distance or worldwide communications computers are usually connected into a wide area network to form a single integrated network.
Networks can be linked together by telephone lines or fibre-optic cables. Modern telecommunication systems use fibre-optic cables because they offer considerable advantages. The cables require little physical space, they are safe as they don't carry electricity, and they avoid electromagnetic interference.
Networks on different continents can also be connected via satellites. Computers are connected by means of a modem to ordinary telephone lines or fibre-optic cables, which are linked to a dish aerial. Communication satellites receive and send signals on a transcontinental scale.