Information Technology

Subject Name: Information Technology

Subject Code: BSBC 104 

Diploma in Computer Application

Objective:  This course will enable the student to gain an understanding of the core concepts and technologies which constitute Information Technology. The intention is for the student to be able to articulate and demonstrate a basic understanding of the fundamental concepts of Information Technology.

Unit –I Computer Fundamentals:

1. Block structure of a computer
2. Characteristics of computers
3. Problem solving with computers
4. Generations of computers Classification of computers on the basis of capacity, purpose, and generation. 
5. Number System: Bit, byte, binary, decimal, hexadecimal, and octal systems, conversion from one system to the other, representation of characters, integers and fractions
6. Binary Arithmetic: Addition, subtraction and multiplication

1. Block structure of a computer

Block diagram of a computer gives you the pictorial representation of a computer that how it works inside. Or you can say that, in computer's block diagram, we will see how computer works from feeding the data to getting the result.

Mainly computer system consists of three parts, that are central processing unit (CPU), Input Devices, and Output Devices. The Central Processing Unit (CPU) is divided into two parts again: arithmetic logic unit (ALU) and the control unit (CU). The set of instruction is in the form of raw data.

A large amount of data is stored in the computer memory with the help of primary and secondary storage devices. The CPU is like the heart/brain of the computer. The user does not get the desired output, without the necessary option taken by the CPU.  The Central processing unit (CPU) is responsible for the processing of all the instructions which are given by the user to the computer system.
Here is the block diagram of a computer system:

The data is entered through input devices such as the keyboard, mouse, etc. This set of instruction is processed by the CPU after getting the input by the user, and then the computer system produces the output. The computer can show the output with the help of output devices to the user, such as  monitor, printer, etc.

CPU (Central Processing Unit)
Storage Unit
ALU(Arithmetic Logic Unit)
Control Unit
Central Processing Unit (CPU)
The computer system is nothing without the Central processing Unit so, it is also known as the brain or heat of computer. The CPU is an electronic hardware device which can perform different types of operations such as arithmetic and logical operation.
The CPU contains two parts: the arithmetic logic unit and control unit. We have discussed briefly the arithmetic unit, logical unit, and control unit which are given below:

Control Unit

The control unit (CU) controls all the activities or operations which are performed inside the computer system. It receives instructions or information directly from the main memory of the computer.

When the control unit receives an instruction set or information, it converts the instruction set to control signals then; these signals are sent to the central processor for further processing. The control unit understands which operation to execute, accurately, and in which order.

Arithmetic and Logical Unit
The arithmetic and logical unit is the combinational digital electronic circuit that can perform arithmetic operations on integer binary numbers.It presents the arithmetic and logical operation. The outputs of ALU will change asynchronously in response to the input. The basic arithmetic and bitwise logic functions are supported by ALU.

Storage Unit

The information or set of guidelines are stored in the storage unit of the computer system. The storage unit provides the space to store the data or instruction of processed data. The information or data is saved or hold in computer memory or storage device. The data storage is the core function and fundamental of the computer components. 

1.1. Components of Computer System

The hardware and software exist on the computer.  The information which is stored through the device is known as computer software. The hardware components of the computer system are related to electronic and mechanical parts, and the software component is related to data and computer programs. Many elements are connected to the main circuit board of the computer system called a “motherboard.”

These are mainly five components of the computer system:

Processor.
Main Memory.
Secondary Memory.
Input Devices.
Output Devices.

Processor
The processor is an electric circuitry within the computer system. The Central processing unit is the central processor or main processor of the computer system. The processor carries out the instructions of the computer program with the help of basic arithmetic and logic, input/output operations.

Main Memory  
The Random Access Memory is the main memory of the computer system, which is known as RAM.  The main memory can store the operating system software, application software, and other information.  The Ram is one of the fastest memory, and it allows the data to be readable and writeable.

Secondary memory
We can store the data and programs on a long-term basis in the secondary memory. The hard disks and the optical disks are the common secondary devices. It is slow and cheap memory as compare to primary memory. This memory is not connected to the processor directly.

It has a large capacity to store the data. The hard disk has a capacity of 500 gigabytes. The data and programs on the hard disk are organized into files, and the file is the collection of data on the disk. The secondary storage is direct access by the CPU; that’s why it is different from the primary storage.

The hard disk is about 100 times the capacity of the main memory. The main difference between primary and secondary storage is speed and capacity. There are several large blocks of data which are copied from the hard disk into the main memory.

Input Devices
The user provides the set of instruction or information to the computer system with the help of input devices such as the keyboard, mouse, scanner, etc. The data representation to the computer system is in the form of binary language after that the processor processes the converted data. The input unit implements the data which is instructed by the user to the system.

We can enter the data from the outside world into the primary storage as the input through input devices. The input devices are the medium of communication between the outside world and the computer system. There are some important features of input devices which are given below:

• The input devices receive or accept the data or instruction from the user, who exist in the outside world.
• These devices convert the data or instruction into the machine-readable form for further processing.
• The input device performs like the connection between the outside world and our computer system.
• The keyboard and mouse are common examples of input devices.
• When the whole procedure is finished, we get the desired output from the output devices such as monitor, printer, etc.

Output Devices
The output devices produce or generate the desired result according to our input, such as a printer, monitor, etc. These devices convert the data into a human-readable form from binary code.

The computer system is linked or connected to the outside world with the help of output devices. The primary examples of output devices are a printer, projector, etc. These devices have various features which are given below:

• These devices receive or accept the data in the binary form.
• The output devices convert the binary code into the human-readable form.
• These devices produce the converted result and show to the user.

Characteristics of Computers

The characteristics which make the computer make indispensable are

1. Speed

The computer is able to process the data and gives the output in fractions of seconds, such that required information is given to the user on time enabling the user to take right decisions on right time. A powerful computer is capable of executing about 3 million calculations per second.

2. Accuracy

The accuracy of computers is consistently high enough which avoids any errors. If it all there are errors, they are due to errors in instructions given by the programmer.

3. Reliable

The output generated by the computer is very reliable, but it is reliable only when the data, which is passing as input to the computer and the program, which gives instructions are correct and reliable.

4. Storage Capacity

The computer has a provision to store large volumes of data in the small storage devices, which have the capacity to store huge amounts of data and help the retrieval of data an easy task.

5. Versatile

Computers are very versatile machines. Computers are capable of performing almost any task, provided the task can be reduced to a series of logical steps.

6. Automation

Once the instructions fed into the computer it works automatically without any human intervention until the completion of execution of a program or meets logical instructions to terminate the job.

7. Diligent

A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability, it overpowers human being in the routine type of work

3. Problem solving with computers

Problem Solving
Solving problems is the core of computer science. Programmers must first understand how a human solves a problem, then understand how to translate this "algorithm" into something a computer can do, and finally how to "write" the specific syntax (required by a computer) to get the job done. It is sometimes the case that a machine will solve a problem in a completely different way than a human.

Problem Solving
Computer Programmers are problem solvers. In order to solve a problem on a computer you must:

• Know how to represent the information (data) describing the problem.
• Determine the steps to transform the information from one representation into another.

Algorithm
An algorithm (see Algorithm) is a set of specific steps to solve a problem. Think of it this way: if you were to tell your 3 year old neice to play your favorite song on the piano (assuming the neice has never played a piano), you would have to tell her where the piano was, and how to sit on the bench, and how to open the cover, and which keys to press, and which order to press them in, etc, etc, etc.

The core of what good programmers do is being able to define the steps necessary to accomplish a goal. Unfortunately, a computer, only knows a very restricted and limited set of possible steps. For example a computer can add two numbers. But if you want to find the average of two numbers, this is beyond the basic capabilities of a computer. To find the average, you must:

First: Add the two numbers and save this result in a variable
Then: Divide this new number the number two, and save this result in a variable.
Finally: provide this number to the rest of the program (or print it for the user).

Flowcharts

Flowchart is a graphical representation of an algorithm. Programmers often use it as a program-planning tool to solve a problem. It makes use of symbols which are connected among them to indicate the flow of information and processing.
The process of drawing a flowchart for an algorithm is known as “flowcharting”.

Basic Symbols used in Flowchart Designs

Terminal: The oval symbol indicates Start, Stop and Halt in a program’s logic flow. A pause/halt is generally used in a program logic under some error conditions. Terminal is the first and last symbols in the flowchart.

Input/Output: A parallelogram denotes any function of input/output type. Program instructions that take input from input devices and display output on output devices are indicated with parallelogram in a flowchart.

Processing: A box represents arithmetic instructions. All arithmetic processes such as adding, subtracting, multiplication and division are indicated by action or process symbol.

Decision Diamond symbol represents a decision point. Decision based operations such as yes/no question or true/false are indicated by diamond in flowchart.

Connectors: Whenever flowchart becomes complex or it spreads over more than one page, it is useful to use connectors to avoid any confusions. It is represented by a circle.

Flow lines: Flow lines indicate the exact sequence in which instructions are executed. Arrows represent the direction of flow of control and relationship among different symbols of flowchart.

Example : Draw a flowchart to input two numbers from user and display the largest of two numbers

4. Generations of computers

Generations of computers Classification of computers on the basis of capacity, purpose, and generation.

Classification of Computers
The Computer is a device that accepts information and manipulates it for some results based on a program or sequence of instructions on how the data is to be processed. There are different types of computers available in the markets that are used to perform different tasks. The computers can be classified into different categories on the basis of :
 Generations
 Sizes/Capacity
 Data processing techniques

Classification of Computers on the basis of Sizes or Capacity:

The computers vary in their sizes, speed and data storage capacities. On the basis of sizes and storage capacities the computer can be classified as:

 Super computers
 Mainframe computers
 Mini-Computers
 Micro-computers

Classification of Computers on the basis of Data Processing Techniques

On the basis of purpose/ data processing techniques the computers can be classified as:
Analog Computers
Digital computers
Hybrid Computers

5. Number System:

Bit, byte, binary, decimal, hexadecimal, and octal systems, conversion from one system to the other, representation of characters, integers and fractions.