Information Technologies Dersi 1. Ünite Özet

Introduction To Information Technologies

Özet

Introduction

Concepts of data, information, knowledge, and wisdom (in short, DIKW) are the building blocks of information science. Data are symbols representing the features of objects and events. They are unprocessed collection of raw facts gathered from various sources explicitly or implicitly and do not have any values without making them useful, that is, without being converted into the information. Data can be divided into two different types: categorical and numerical. Categorical data can be sorted into the categories of values or observations and grouped as nominal or ordinal. The main difference between these two groups, in the ordinal data, the categories are in certain orders. Unlike numerical data, categorical data cannot be measured. Numerical data is divided into two types: discrete and continuous. For discrete data, values are countable and can only take particular values. Continuous data are not restricted to defined distinct values. Measured values or observations may take any value within a specified range for these data. Information is generated by processing data. During the processing, data is transformed into a meaningful form and its usefulness increases. Information is the data that represent the relational connection. Thus, the difference between data and information is functional, not structural. Knowledge is a collection of relevant information. It is a deterministic process that involves transformation of information into instructions. Wisdom corresponds to the ability to see the long-term consequences of any act and to evaluate them relative to the ideal of total control. It includes the exercise of judgment or decision.

Representation of Information

In order to enable the use of the resulting data (information) by the computer, accurate measurements should be converted into numerical values (numbers) by certain mechanisms. Those numerical values can be converted into various data formats and can be converted back into the original ones.

Number Systems: The most common number system used in our daily life is decimal number system (base 10) containing 10 digits: 0 through 9. In all number systems, numbers start from zero to the “base - 1”, which is the largest number that can be written. On the other hand, if the base exceeds 10, additional digits use letters of the alphabet beginning with A. An electrical circuit has only two states: ON and OFF. The binary number system has only two values corresponding to these states that represent high and low voltage levels, “1” (5 V) and “0” (0 V). These values are simply called as binary digits (bit, denoted by ‘b’) in computer systems. In computing, other than binary, octal and hexadecimal number systems are also used as more compact forms for representing binary numbers. In computer systems, a byte (denoted by ‘B’) is a unit of data that consists of 8 bits. It is used to represent a character. A nibble is half byte. A word is a standard memory bus width in computer architecture. It can have a length of 16 bits, 32 bits, 64 bits etc. In a number system, the positions to the left of the radix point have positive powers whereas the positions to the right of the radix point have negative powers. In any case, any number raised to its zeroth power is always 1, so the position to the left of the radix point (first digit - digit 0) is always 1. The second digit to the left of the radix point has a value of r ¹ , the third digit has a value of r ² . In the same way but in the reverse direction, the first digit to the right of the radix point has a value of, r ^-1 the second digit has a value of r ^-2 , and so on. In general, the principles that apply to decimal numbers also apply to the numbers in other systems as well. A number with radix r is represented by a set of digits like A _n-1 A _n-2 ...A ₁ A ₀ .A _-1 A _-2 ...A _-m+1 A _-m in which $0\leq A_{1}< r$ and “.” is the radix point. In order to convert a decimal number to another number system, the number is divided by the target base, then the remainders are saved as the digits of the results in reverse order; these two steps are repeated until the quotient is zero. During the conversion from binary to octal, the binary digits are divided into the groups of three bits. Similarly, during the conversion from binary to hexadecimal, the binary digits are divided into the groups of four bits. Then, for octal representation, each group of three bits is converted into octal digit. Similarly, for hexadecimal representation, each group of four bits is converted into hexadecimal digit. Real numbers are represented by floating point numbers that consist of mantissa (fractional part) and exponent (designates the position of the radix point). The floating point standard is defined by IEEE 754 (International Standard for Floating-Point Arithmetic). 4-byte version is called as single precision, and 8-byte version is called double precision. ASCII (American Standard Code for Information Interchange) code is used to represent information such as character-based data. It uses seven bits to code 2 ⁷ = 128 characters. Unicode is a 16-bit code words that extends ASCII to 2 ¹⁶ = 65536 universal characters codes. Since the base coding of Unicode is 16 bits, it has the capacity to encode the majority of characters used in every language in the world.

Information Processing

The extraction of useful information from data is an essential task for information systems. Data is stored, retrieved, processed, transformed and an output is produced finally. In order to convert raw data into useful information, the information processing steps that should be present in the information systems are classified as follows:

Collect: In this process, firstly it should be decided what kind of data are gathered.
Organize: This step is related to providing the appropriate format of data to be used for further processes. It is the formatting process of the data including copying, sorting, grouping, or arranging it in a more convenient way for input. Verification of the collected data is handled in this stage.
Analyze: Interpretation or summarization of data to make the data understandable and easily available is realized in this stage.
Store/Retrieve: In this step, the processes of storing the data and retrieving the previously recorded data or information for further processes/users are realized. Storage devices are used in computers to store the data. There are various types of storage devices. Some examples are random access memory (RAM), read only memory (ROM) and cache as primary storage, hard disk drive as secondary storage, magnetic tape and optical disk as tertiary storage, USB flash drive and memory card as offline storage.
Process: In this step, the processes of achieving a new value for obtaining useful information or changing the data to find the result are realized.
Transmit/Receive: This step is related to the transfer of data and information within the system or between the systems.
Display: It is the process of presenting the information to the user in an appropriate format.

Information Technology in Business

Information Technology (IT) can be described as the study, design, development, implementation, management and support of computer based information systems, especially software applications and computer hardware. IT is based on information exchange, and it is all kinds of visual, audial and written tools that provide generation of information and access to information by following the stages of information processing. Using information technology in business makes it easier for many businesses to stay strong in competition, to set new targets and to reach those targets. Information systems can also help to provide the coordination between business, manufacturing, and global value-adding chain needs. Modern business looks for the IT platform that provides integrated enterprise applications designed for high availability, reliability, and scalability, redundant hardware and networking capabilities, fault tolerant technologies, data replication capabilities, disaster resilient technologies, remote system administration, remote diagnostics, more secure environment with respect to user authentication, intrusion detection, secure transactions.

Electronic business (E-business) can be simply defined as conducting the business via electronic medium, e.g. over the internet. It involves not only buying and selling, but also operating automated, efficient introduction of new organizational structures and work practices supported by available information technology solutions. The main benefits of e-business:

Reducing operating costs of business and its processes and avoiding consumption,
Increasing market opportunity (Faster access to the market and customer trends),
Fast access to customers: enabling them to access the information about products or services they need at any time (7/24),
Elimination of processing errors,
Strengthening internal management,
Supply chain management: Provide uninterrupted (continuous) supply chain,
Reduction of sales cycles,
Increasing visibility,
Communication improvements,
Predicting the fall in the probable life curve of product

The main challenges in e-business are:

Determining customer’s changing needs,
Organizational structure,
The high speed of the development of IT,
Integration of the front and back-end systems of the organization,
A lack of qualified human resources,
The complexity of ensuring security,
Growing competition,
Effective and efficient customer service (high availability, ease of use, personalized systems),
High quality access,
Expensive infrastructure of information system.

Computers

Computer can be simply defined as a digital system that can be instructed to automatically execute an arbitrary set of arithmetic and/or logical operations. The ability of computers to execute user-defined sequences of operations, which are called as programs, enable them to realize a wide range of processes. In general, computers can perform three basic operations. Firstly, they accept data (input) from users via various input devices. Secondly, they process the data. Finally, they store the processed data in a memory or transfer it to various output devices in the desired format. Computers can perform these operations by utilizing specific hardware and software to meet the needs of the users. With the help of computers, it is possible to achieve the correct result by eliminating human factor-induced mistakes and to reduce processing time of operations that people can do in a much longer time with possible processing errors.

Types of Computers: Computers can be categorized into three groups depending on their shapes and sizes:

Desktop computer: A desktop computer is suitable for use at an ordinary desk.
Notebook (or, laptop)computer: A notebook computer is a battery-powered compact computer with integrated keyboard.
Tablet computer: A tablet computer (in short, tablet) is a mobile computer with a touchscreen display and a rechargeable battery in a thin and flat case.

Considering the factors such as operating resources, performance and purpose of use, computers can be also categorized as microcomputer, workstation, minicomputer, mainframe, server and supercomputer.

Microcomputer: It is also called as personal computer (PC). PC is usually used by single person at home, office and business environments. Nowadays, it is the most common type of computer.
Workstation: A workstation is like a PC, but it has more resources in terms of processing power and memory.
Minicomputer: A multi-user computer that support hundreds of users simultaneously.
Mainframe: A very powerful multi-user computer that can support thousands of users at the same time.
Server: A server is similar to a mainframe that serve many uses with the main difference that the users (called clients) do their own processing usually.
Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions (or more) per second using parallel processing.

History of Computers: The history of computers is briefly reviewed below:

The first generation: Vacuum Tubes (1940-1956)
The second generation: Transistors (1956-1963)
The third generation: Integrated Circuits (1964- 1971)
The fourth generation: Microprocessors (1971- Present)
The fifth generation: Artificial Intelligence (Present and Future)

Computer Hardware

Computer hardware basically corresponds to the physical parts of the computer that one can physically touch. Hardware components of a typical computer are briefly introduced below:

Case: Computer case contains several components such as mainboard, central processing unit (CPU, or simply processor), system memory, hard disk drive and power supply unit.
Mainboard: It is located inside the computer case. Mainboard has communication channels and several interfaces to enable communication among internal and external components such as CPU, memory and input/output (I/O) units.
Central Processing Unit: It is located on the mainboard. CPU executes and controls all the processes within the computer.
System Memory: It is the component where data is temporarily stored while processed by CPU.
Hard Disk Drive: It is the component where data is permanently stored after processed by CPU, until changed or deleted.
Optical Disk Drive: It is used to read/write from/to optical discs such as CD, DVD, BlueRay, etc.
Power Supply: It is located inside the case. It simply provides power to the components of the computer at desired levels.
Monitor: The data/information processed by computer is directed to the monitor so that we can see it.
Mouse: It is one of the fundamental input units to achieve certain tasks such as controlling the cursor, etc.
Printer: It is another output unit. Data/ information can be physically printed on papers via printer.
Keyboard: Just like mouse, it is one of the fundamental input units to achieve certain tasks such entering commands, writing text, etc.

Modern computers are generally based on the architecture developed by Von Neumann in 1945. In this architecture, there are three major items, namely CPU (or, simply processor), memory unit, and I/O unit. These items are interconnected through 3 communication channels known as data, address, and control buses. CPU can be simply defined as the unit where data/information processing is carried out. Its purpose is to decode instructions received from memory and perform arithmetic, logic, and control operations with the data availablein memory and/or I/O interface units. Memory is the unit where the data/information is stored. Memory units are mainly divided into two categories: volatile and nonvolatile. A volatile memory keeps the data inside as long as power is on. When power is off, the data inside the volatile memory is lost. On the other hand, a nonvolatile memory keeps the data inside even if the power is turned off. I/O unit essentially involves all input/output the computer could possibly do. The input and output subsystem of a computer provides an efficient mode of communication between CPU and internal/external environment. The data bus is used to transfer data from CPU to memory or I/O unit, or vice versa. The address bus is used to transfer the address of the data to read/write from/to memory or I/O. The control bus is responsible to transfer necessary control signals for particular operations.

Computer Software

Software can be simply defined as the set of instructions for a computer to realize specific operations. Both hardware and software are required for a computer to operate. While hardware cannot be easily updated/upgraded, software can be flexibly and easily changed/updated. Software is developed using various software development models and programming languages based on user requirements. The steps to follow when developing software are determined in the software development life cycle (SDLC). Briefly, SDLC indicates all the stages that the software spends throughout the production and use process. These stages are in the form of a loop because the requirements at these stages are constantly changing. When there is any change at any stage, backward or forward processing can be performed. SDLC for software development can be listed as follows:

Planning: In this stage, preliminary investigations and feasibility studies for identifying problems, opportunities and objectives are carried out and the project plan is established.
Analysis: In this stage, the user requirements are determined and system needs are analyzed.
Design: In this stage, the solution system is defined based on the requirements and analysis decision.
Development (Coding): It is the stage where coding and program development are realized.
Implementation/Testing: It is the transition stage. Testing and implementation is carried out at this stage.
Evaluation/Maintenance: In this stage, the main goal is to keep the system healthy. This stage includes error handling after delivery and new additions to the user requests.

Computer software can be divided into two main categories: system software and application software.

System Software: System software maintains the relationship between hardware and application software. It controls the operations of computer hardware. Utility software, device driver, firmware and operating system are fundamental examples to system software. Operating system is a system software that enables the user to use computer hardware. It acts as an interface between the user and the resources that the computer has. The characteristics of the operating system determine the general behavior of the hardware. The operating system bridges between the hardware and the application software that execute with the user’s request. It is directly responsible for the operation of the computer system. Objectives of the operating system are to execute user programs and make solving user problems easier, to make the computer system convenient to use, to use the computer hardware in an efficient manner. The main tasks of an operating system can be summarized as follows:

Process management: Operating system is responsible for CPU scheduling for processes and threads, process synchronization and communication, creating and deleting user and system processes.
Memory management: Operating system is responsible for allocation and deallocation of memory, following which part of the memory are used and who uses the memory.
Storage management: Operating system is responsible file management, creating, deleting, and manipulating files and directories, mapping files onto secondary storage, disk scheduling and storage allocation, controlling the I/O devices through the device drivers.
Protection and security: Operating system is responsible for controlling the access of processes or users to the resources defined by a computer system, providing system protection by preventing external and internal attacks (it is optional for operating systems).

Application Software: Application software is a program developed specifically for end users. They are dependent on the operating system, that is, an operating system installed on the computer must be available for an application program to execute. There are application software that can run on different operating systems while there are some others that can run only on a specific operating system. Application software can be classified into two categories, general and special purpose software. General-purpose software are developed to allow people to do their jobs effectively, quickly and efficiently. Special purpose software are mainly used for analysis, decision making, planning, programming, coordination, and organization purposes.