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IT is one of the youngest and most complex scientific disciplines. Developed as an independent scientific discipline sixties in the U.S. and the UK. It emerged as a unification of the achievements of a number of science as: formal logic, mathematics, information theory, electronics, and others, which makes it complex. Since it is a relatively young science informatics, increasingly present in the activity of man in very diverse systems, it is necessary to know its definition and scope of activities. Generally, the system defines the following three features:

Statement 'The Bridge is a creation of a movable bridge system' is best describes the relationship between these concepts. The bridge is a structure composed of the elements that make a whole without isolated components (subsets) and operates independently with a purpose. Movable bridge acts as a system even though the bridge formation. Movable bridge and management mechanism with it can be as individual elements are seen as creations because they work independently with a purpose. Movable bridge opens the passage as needed or at a specified time and works as a system.

Tank for water is not a system, but if you add a heater and a heat regulator that supervises ga then becomes the system. So when it comes to water, but these are some, for example in the delta of the river built irrigation canals. An irrigation ditch was observed independent entity, as well as other channels in its vicinity. If the channels are interconnected into a functional unit that soaking water surrounding agricultural lands represent (constitute) an irrigation system. Therefore, the system is a set of interconnected elements-creations, which act in order to achieve the role of the system. What is one stone work in the channel of the many stones that are incorporated into the channel? Replace the stone from the computer!

Informatics is the scientific discipline that studies the principles and operation of mixed system, primarily: human - computer. Engaged in the research, development and use of methods and devices for structuring, processing and transmission of data. Informatics and information are by no means the same terms and must be separated. In essence, can be seen as two different entities.

These forms of literacy are certainly not the same, but for the second one and they need certain skills, but the informatics literacy requirement for informational literacy. This electronic book is to contribute to informatics literacy and ECDL is the logical choice to him. Technical and engineering approach requires a thorough basis of ECDL and therefore covered by this tutorial. Informational literacy is a much more elaborate theme in a variety of different industries seeks knowledge, but the common denominator is the same: to collect and process information and make a decision (he! what?). Therefore, informatitians (IT specialists) 'fuss' by computers or network devices to be usable, while informatologies trying to use the computer in the domain of their work quality and process used available information.

Discipline, which is increasingly becoming part of the education program Computer Science - the science that deals with the study of computers and the procedures that apply to computers. Refers to the basic structure and principles of operation of electronic computers and their application; mathematical logic, theory of computation, algorithms, data structures, programming languages, software engineering, computer architecture, communications and more. Vocational oriented approach. This tutorial by its contents belong to this area.


There are many definitions of the science of informatics and still does not have a universally recognized definition that would encompass all areas of information technology which includes, but here are fundamental:

       French Academy of Sciences (1966) - Informatics is the science
              on rational information processing,
              primarily by automatic machines,
              as the holder of knowledge and communication in the fields of science,
              technology, economics, and other areas of human activity.

       General Encyclopedia (1966) - Informatics is the science
              discipline that studies the structure and properties
              (but not the content) information, and the legality
              information activity, its theory, history,
              methodology, organization and efficiency.

The term 'Informatics' is used in different countries with different interpretations and hence the variegated definitions. Comes from the French words INFORMATION and AUTOMATIQUE, as a synonym for Automatic Data Processing (ADP). Linked by two concepts: information and automatic machines (computers).

Therefore, INFORMATICS (IT) is the science that deals with the structuring, processing and transmission of data, with an emphasis on information, and the procedures and methods of data processing, with emphasis on computers, their structure, operation and use of what we are in some areas significantly overlap with the subject matter of at length with COMPUTER SCIENCE. Informatics and Computer Science are not the same, although they are closely related because they cover the same or similar subject matter, but her differing approach. In essence, the case dealing with the Informatics (IT) development of optimal methods and means to retrieve, transfer, receipt, storage, processing and use information.

Efficient operation of information technology is tightly coupled to the computer as a significant factor in the processing of information, and it is no wonder that the name 'Informatics' is often synonymous with the study of computers and their use, even though the computer as an effective tool used by IT just a few decades. Result of the development and application of advanced technologies and electronics makes the computer accessible and effective means of IT.

The development of electronics, especially in the manufacture of integrated circuits, made possible the development of low-cost computing machines (every day more numerous), which not only performed by counting a number of logical actions regarding facilitating the resolution of complex tasks. Besides, the increased reliability of multiple computer systems, and the dimensions are reduced to the extent affordable desk, computer makes it acceptable for personal use, the economy and society as a whole. The ability to manage processes, simulation and robotics are the new future of man pages enabled computer science and its achievements.

The basic element of computer technology in everyday practice, a MICROPROCESSOR, a collection of millions of transistors integrated in a small enclosure no bigger than a box of matches, the backbone of micro-computer system, which can be programmed to perform tasks according to user preference. Of course, more powerful computers (mini and mainframe systems, and similar) with the complex structure of a processor can execute more complex tasks of microcomputers, but are not the subject of widespread everyday use. But the principles of operation are consistent with them. The purpose of processor is essentially DATA processing, according to the PROGRAM, and is based on the findings in the current data acquired new knowledge as a product of their processing.

Data is basically a MESSAGE that may or may not use. If there is the slightest chance that the message uniquely and accurately used, and presents indisputable facts, then present INFORMATION. Thus, each message may or may not contain the information.

It is essential that the computer data processing result display or sends the information to the user receives treatment in an appropriate manner, and to create COMMUNICATION and make information sharing. State or process material system that transmits information (message) from the source to the destination in a format suitable for transmission is called the SIGNAL (acoustic, electric, lighting, etc.), and the medium through which the signal passes through is called the TRANSMISSION PATH.

Converting messages to perform signal transmitting device and convert the signal to the receiving device performs the message, and the overall message transfer system is a communication system. Shannon's communication system model is shown in Figure 1.1.1.

 Communication system by Shannon
Figure 1.1.1 Model of the communication system.

The message is the product of the source of information. An everyday example is the telephone when a man say things meaningful message contained in the acoustic signal, which turns the microphone into an electrical signal, which is then transmitted via a system of guides to other phone and headset again converted into acoustic signals that are recognized as the recipient of the message. Technically designed a portable system called the COMMUNICATION CHANNEL, which is of course part of the entire COMMUNICATION SYSTEM. The communication channel is a set of devices which provide a SIGNAL on the transmission path, and in the simplest mode to Figure 1.1.1 that the transmitter and receiver transmission path. Noise and interference (accidental or deliberate) can completely prevent the receiver from the received signal to 'pull out' message, or whether the communication channel can be connected by the third person to the data communication channel is transmitted to intercept and steal them, or fix interfere with or perform some other action regarding the achievement of some commonly used illicit. Therefore, the data of interest is always transmitted ENCRYPTED communication channel.

Transmission of data, news or notifications between humans and the mechanism or of both together, is required in the global - the broadest sense as communication is a very complex process. In relation to this problem is multi-disciplinary and researched it interfere with other scientific disciplines such as: psychology, biology, philosophy, telecommunications and more. Global: communication encompass ways, mechanisms and media involved in the transmission of information.

Information is a word of Latin origin and means notification, communication, data or messages. Word of communication also has its roots in Latin, meaning exposure or intercourse. Information, in the broadest sense, considered here, deals with the area of electronics called telecommunications. Telecommunications devices are part of our everyday life, such as TV and radio, devices for receiving image and audio messages that can contain some information.

The notion of information we mean data on the results of an event that is about to happen or has already happened, but the outcome was not known. Information removes the uncertainty. The fact is over the facts, and information is the meaning attributed to the data. For example, the result of football competition Real Madrid : AFC Ajax = 2 : 0 (data) means that Real Madrid won the match (information). Information is a measurable quantity, and is directly related to the probability of the occurrence of which informs us. So it is said that a notification had a much greater amount of information, if it is less likelihood of the occurrence of which informs us. The signal itself is also information. Information is transmitted signals. A letter or other communication medium composed of characters who understand both parties, can be termed as the carrier signal information.

Communications must answer three questions:

Different types of messages, and hence the possible information can be grouped as follows:

Electrical signal, as a direct carrier of information is of particular importance. But it's not the only one. Speak into the telephone handset devices (transmitting), speech organs produce an acoustic signal that the microphone is converted into an electrical signal which now contains voice information. At the reception the electrical signal through the speaker again transformed into an acoustic signal is almost identical to the source, which is now handled auditory organs (receiving).

Precisely: In the brain of one man (source) invents the content (message) and the human brain system 'forcing' the oscillation of the vocal folds throat from the conception of the brain, which means the mouth causing the desired vibration of air molecules to vibrate in accordance with the oscillation of the vocal folds (acoustic signal). This means that the membrane microphone operates variable sound pressure that causes its mechanical vibrations (mechanical signal) in accordance (analog) with the vibrations of air molecules. As the membrane microphone attached coil placed in a magnetic field, according to the law of induction, moving coil in a magnetic field induces a current in it and creates an electrical signal by changing the shape of analogous acoustic signal. This signal is amplified (transmitter) and sends e.g. via wires (transmission path) device that reads it, if necessary, amplifies and sends the speaker (receiver). The speaker has a membrane that is attached to a coil placed in a magnetic field, and the current passing through it causes a changing magnetic field, by adding and subtracting the magnetic field magnet speakers, causing mechanical vibration speaker membrane, and the mechanical oscillation of the membrane causes the vibration of air molecules (acoustic signal) that registers the human ear of another man, and through the mechanism of the human auditory brain sent another man (destination) change of oscillation of air that is read by the ear (message) and translate the brain in the best way possible. Therefore, the signal at transmission path can experience a variety of physical transformations.

As the form of the acoustic signal of speech agrees with the shape of the signal that is transmitted communication system and an almost identical form of the acoustic signal at the destination, and by the shape of the transfer is not experiencing changes and accurately monitor changes in the source, such a signal is called an ANALOG SIGNAL.

 Undistorted analog signal
Figure* 1.1.2 Time view size of the analog signal. ( +/- )

During the passage of conductor (transmission path) signal is subjected to interference and distortions which may result in some incomprehensible messages in the destination. For instance, distortion looks beep than 1% but noticeable human ear. Distorted shape of the signal, as shown in Figure 1.1.2b, means and disorder to an extent that it may become unusable. Pointed sudden changes of amplitude in the communication channel can arise, for example, when transferring a signal as a result of atmospheric discharges or other electromagnetic interference. When former 'vinyl' musical plate resulting scratches the surface of the plate containing the etched spiral groove which changes shape changes shape analog electrical signal which can be controlled with a grooving in vinyl. Damage to the spiral shape grooves human ear recognized as a 'crunch' when playing on the turntable.

Understandable message, after which follows right action represents - contains the information.

Information source can deliver the message in a different way. The message is as AGREED by the source and destination turns into a signal composed of a combination of pulse light, acoustic, written, etc., each of which represents particular combination of a character, as in Morse's alphabet. Anyone who sends a message as combinations of pulses by appointment, expected to be the recipient who respect the agreement to understand his message. The human brain is the one that performs the conversion of spoken or written, or any other messages in the message in the form of a sequence of pulses. The computer will do the conversion message electronic logic circuits and devices. Such a transfer pulses of unequal length and unsuitable for rapid communication, and computer technology is adopted more consistent mode of transmission of impulses. For example, pressing the computer KEYBOARD (or TTY) creates the appropriate sequence IMPULSE identical in shape and length of the sequence (number of seats for the pulses), but differs in the number of pulses in the sequence and their distribution within the sequence for each character keyboard. Such a sequence is sent to your computer with a keyboard and contains a message about the pressed key and accompanying her character (Figure 1.1.3).

 Undistorted digital signal
Figure* 1.1.3 Sequence of pulses of 8 places for two different characters. ( +/- )

In the same way the messages exchanged between the computer by an agreed signal table for each character. As the number of sites, the number of pulses in the sequence and their mutual arrangement of the elements within the sequence of a number system, and the computer recognizes the received sequence as the appropriate NUMBER, the signal shown in the Figure above is called a DIGITAL SIGNAL (digit = number).

The shape of the pulse is not essential for the transmission of messages in the form of a digital signal and is allowed and a certain distortion of the pulse shape, even more than 50%, as shown in Figure 1.1.3b. It is important to identify the destination of its existence and not the form, which suggests that the transfer of digital information signal significantly more interference than analog signals, and thus more reliable. Very often the situation 'without pulse' reported as negative impulse (character ' IIb '), which further improves the resolution between the two possible states of the observed time span, thereby contributing to security in recognition. Since the messages contained in the existence (presence) of rectangular pulses, and not in his form as at the analogue signal, during the 'passage' through the transmission path form of digital signals can be REGENERATED, i.e. 'fix' shape of pulses if the pulses are significantly distorted. Basically all devices that 'processed' digital signal on the transmission path are designed to carry out regeneration. Because this is the future of all communication systems based precisely on the use of digital signals for transmission of messages. Computers work is based on the use of digital signal belong to the group of DIGITAL COMPUTERS and such are almost all computers today.

Handing message digital computer user is usually in the form of the imagery we have already known characters (letters, digits, dot, etc.) on the monitor screen. Keyboard and monitor, two main devices to communicate with your computer, call the CONSOLE or TERMINAL, depending on how you communicate with the computer.

Under the default console to the monitor and keyboard connected directly to the computer, and that term is now considered to be a direct approach and work at a central or common computer (server) via its own monitor and keyboard. Terminal default means access to a remote computer through some computer networks, where the keyboard and a monitor connected to another computer (client) you are via a communication channel access remote computer (server) in a way that the image on the monitor client sends the server. Sometimes the terminals were physically independent electronic devices without software support, they had a part to establish communication and display images on the screen that he was sending a remote computer. Today, the term used when a terminal from a remote PC emulates - 'acts' as the work of a former physical terminal adequate software support.

Today's average computer users have their own monitor and keyboard, and supporting software and hardware support, and self-employment in respect of data processing. As a rule, are in some way part of a computer network, modem, network card, or something else, and is commonly referred to as 'Workstation' or 'PC' (Personal Computer - host).

There is an ANALOG computers that are used for processing the analog signal. But they are very expensive and technologically complex, and as the technology has enabled a reliable and affordable conversion of analog to digital (A/D) and vice versa (D/A), with especially designed for this purpose converters, digital computers are highly successful (and even better) handle analog signals. The combination of analog and digital computer called HYBRID COMPUTER.

Communication itself between the receiver and the transmitter is shown in Figure 1.1.1 is a one way and happens to be one communication channel (SIMPLEX). An example of such communication is the acceptance and processing of TV signals. If one communication channel used for communication in both directions, but alternately (HALF-DUPLEX), both participants must have a receiver and transmitter circuits and for their connection to the AC transmission path. Simultaneous two-way communication through one channel (DUPLEX) is only possible in some form of communication and application specific hardware solutions, such as telephone communications. With two separate communication channels can be evaluated receipt and delivery of messages in both directions simultaneously (FULL-DUPLEX) communication resources are fully tandem and each of them a one-way function independently as a SIMPLEX.


 Analog clock  Digital clock The difference between the concept of analog and digital shows most vividly as possible version of hand or wall clock. Time on an analog clock is identified by a clockwise position which is, simplified constantly moving in a circle and its position in the circle and numbers at perimeter of the circle indicate the time, and the position of the clockwise, without numbers, suggest to a human currently time. Digital clock, unlike analog, shows time as decadal numbers and visible changes are taking place at same regular intervals. Does this mean that the scout using a digital clock can not determine the geographic south during the day? No! Value of time reading on the digital clock is easy to draft in the form of an analog clock on the paper and orientation is possible by using the drawn clock.

The literature often describes an analog signal as a CONTINUOUS and digital signal as a DISCRETE. Discreteness describe defined conditions or levels of signals observed in the set of jumps for one of the parameters, such as time. The signal from Figure 1.1.3 that relates to a ' IIb ' can be argued that it is continuous. When such a signal passes through telecommunication channels for the effects of noise, interference and propagation of several different conditions 'resembles' analog signal, but are formulated preserved and easily recognizable. The term is associated with the discreteness of the signals and their analysis and can be used in both types of signals. For example, the A/D, D/A conversion term discretion is entirely something else. Concerns the quality of conversion to an analog signal to digital and vice versa, and has nothing to do with the very nature of digital signal propagation along the communication channel, and its conversion into another form in the process of delivery and receipt of messages.

The pulse sequence is contained in one or more characters, but according to its duration. The entire sequence, which is the deliberate arrangement of characters, contains a message-information. As is true for any kind of content (volume), so for information, means that it is measurable, either as the number of pulses or characters per second, or some other measure.

It is usually said that there is little or a lot of information, and that is good or bad, true or false, they are subjective terms unacceptable in computer technology. Therefore, the information necessary to define the applicable criteria to determine the AMOUNT of her within a message or some of its other parameters. These are all elements of information theory.


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