Introduction to Computers

Basic Computing

We find computers everywhere around us, at home, in schools, hospitals, railway stations, airports, banks, shopping malls and so on. Before we proceed with our study of computers, let us first of all define a computer. A computer is an electronic machine that takes an input, processes it to produce the desired output. Every computer is a combination of hardware and software. The physical components of a computer that can be seen and touched form the hardware. For example, CPU, monitor, keyboard, printer etc., are hardware or peripheral devices. The input to a computer is given in the form of instructions. These set of instructions that we give to the computer to perform a particular task constitutes a program. Many such programs together form a software for the computer. Operating system, Antivirus, MS Office, Computer games are all software applications. In this lesson, you will learn about, the basic components of a computer along with their functions.

What is Computer?

A computer is a programmable electronic device that stores, retrieves, and processes data. Used for tasks like typing documents, browsing the internet, and playing game. It is combination of hardware and software. The monitor, keyboard, mouse, Central Processing Unit (CPU),

Motherboard, printers, scanners come under hardware. Then we have the operating system, which is a system software and then MS-Office/OpenOffice, web browsers are the different types of application software’s or computer programs.

Difference between Hardware and Software

Hardware is the physical components of a computer system that can be seen and used to physically store and perform the operations on the data whiles Software is a computer programs that enables users to interact with computer hardware. It is where the information is processed into data.

Hardware have physical existence, you can touch them. But software’s have logical existence. You cannot touch them but they are essential.

Computer hardware can be categorized as input devices, output devices and storage devices. And Software can be categorized into two parts, System software and application software.

To function properly, the computer needs both hardware and software. Software works as intermediate between user and hardware.

The working of a computer can be well understood by the block diagram shown

Central Processing Unit

Input Unit Arithmetic Logic Unit Output Unit

Control Unit

Memory

Information Processing Cycle

The information processing cycle is the series of steps that a computer follows to process data into information. The four main steps of the information processing cycle are input, processing, storage and output,

Stages/Phases of information Processing Cycle.

The stages of the information processing cycle are as follows:

Input Stage: This is the first step of the cycle, where the computer receives information from the outside world. This information can come from a variety of sources, such as a keyboard, mouse, microphone, or camera. The computer uses special hardware and software to convert the information into a form that it can understand and use.

Processing Stage: In this step, the computer uses its central processing unit (CPU) to perform calculations and logical operations on the input data. The CPU is the “brain” of the computer, and it is responsible for executing the instructions of the programs that the computer is running. In this step, the computer may also access data and instructions from its memory, both primary storage and secondary storage, in order to complete the processing. After the processing is complete, the computer may also write the processed data back to its memory for future use. This step is where the computer “thinks” and makes decisions based on the input data.

Output Stage: After the computer has processed the data, it produces a result, which is called the output. This output can be in the form of a visual display, such as on a monitor or screen, or it can be in the form of a sound or other physical sensation. The output is the information that the computer provides to the user or to another system.

Storage Stage: In the final step of the cycle, the computer stores the processed data in its memory for future use. The computer has two types of memory: primary storage, which is located inside the computer and is used to store data and programs that are currently being used, and secondary storage, which is located outside the computer and is used to store data and programs that are not currently being used. By storing the processed data in its memory, the computer can access it again in the future, without having to process it again from scratch.

The information processing cycle is an important concept in computing, because it helps us understand, how computers work and how they are able to solve problems and produce results. By understanding the information processing cycle, we can design better computer systems and programs that are more efficient and effective.

Devices used in each stage of the information processing Cycle

Input Devices:

Processing Devices:

As mentioned earlier, the CPU is the ‘Brain of a computer’. This is because it processes or executes the instructions given to the computer. Any type of instructions given to the computer using any of the input devices has to be sent to the CPU for execution. In a microcomputer, the CPU is based on a single chip called the microprocessor. A typical CPU has the following components:

· Control Unit (CU)

· Arithmetic Logic Unit (ALU)

· Memory Registers

Control Unit (CU): The Control Unit manages the instructions given to the computer. It coordinates the activities of all the other units in the system by instructing rest of the components of the computer. It reads and interprets instructions from memory and transforms them into series of signals to be executed or stored. It also directs the movement of these electronic signals between memory and ALU or between CPU and input/output devices. Hence, it controls the transfer of data and information between various units. The user’s program provides the basic control instructions. Conceptually, the control unit fetches instructions from the memory, decodes them and directs the various units to perform the specified functions.

Arithmetic Logic Unit (ALU): Arithmetic Logic Unit or ALU performs two types of operations – arithmetic and logical. Arithmetic operations are the fundamental mathematical operations consisting of addition, subtraction, multiplication and shifting operations. Logical operations consist Boolean comparisons such as AND, OR and NOT.

Memory Registers: The CPU processes data and instruction with high speed. There is also movement of data between various units of the computer. It is necessary to transfer the processed data with high speed. So the computer uses a number of special memory units called registers. A memory register is a sort of special storage area that holds the data and instructions temporarily during processing. They often hold data for less than a millisecond. This high speed storage area makes processing more efficient. The contents of the memory is stored only as long as the microcomputer is turned on. When you turn the machine off, the contents are lost. The capacity of the memory to hold data and program instructions varies in different computers. The original IBM PC could hold approximately several thousand characters of data or instructions only. However, modern microcomputers can hold millions or even billions of characters in their memory.

Output Device:

Storage Devices: