Computers are multi-purpose machines that can be used to solve
variety of problems in different fields. Computers have changed the way
we live, work and communicate. Computers are useful in industries,
government, education, research as well as entertainment sectors. From
routine business activities in a given area to a spectacular task,
computers are applicable everywhere. That is why a computer is called
multi-purpose machine.
Working of a Typical Computer
Just as a calculator calculates, a driver drives and a painter paints, computer computes. The computing here is not restricted to only mathematical computing but to a variety of logic based tasks. One only needs to systematically design step by step clear guidelines for the task to be solved. These guidelines generally written in simple English language are called algorithm. Computer once given proper set of instructions can perform operations like generating bills, reserving tickets, printing mark-sheets, printing business reports or communicating messages. Computer can also deal with audio, video, graphs and animations besides texts and numbers.
Once the computer is given data and step by step instructions, it then performs computations and generates result or performs an action as an output. The set of data and instructions provided by a user to the computer is called an input. Computer processes this input and presents results to the user. The result is called an output. Computer can remember these data, instructions and calculated results for future use by storing the details in memory. This simple flow of working of computer is shown in figure 1.1
Further, it is not compulsory to repeat the instruction and enter
large amount of data every time we use the computer. We can store the
data and instructions within the computer itself in such a way that it
can be understood by machine; that is, in machine readable language.
Storing such set of instructions is useful for repetitive performance of
the tasks. Once the set of instructions in machine readable format
called program is stored in the computer, it can be used many times with
different sets of data. This concept is known as stored program
concept.
Following sample list presents some sample application to highlight use of computers in different areas:
The simple model of a typical computer is based on the working of computer shown in the figure 1.1. As we discussed, instructions are needed to make computers perform some actions. To obey instructions provided by the user and perform computations, a computer needs to have a mechanism to input. This mechanism is called input unit. Devices used for the input purposes are known as input devices. Typically input devices such as mouse and keyboards are used for this purpose.
Input provide through the input mechanism is stored in memory of the computer and further processed by a mechanism called processing unit or processor. Results are presented to the user through output mechanism called output unit. Typical output devices are monitor and printer. In short the input, memory, processor and output are the basic components of a typical computer.
Input Unit
The input provides a facility to enter data and instruction into the computer. Input mechanism supports many devices such as keyboard, mouse, joystick, barcode reader, universal serial bus (USB) devices, hard disk and compact disks (CDs). Different input devices take data in different forms and send it to the computer memory. Fro example, use of keyboard to enter data and instructions is very much similar to the use of a typewriter. Another way to input data is reading through barcode reader. Barcode reader is normally seen at superstore. Remember when you purchase a pack of biscuits, the shopkeeper uses a small device and presses a button on the device. With sound of a beep, the barcode printed on a tag of the biscuit pack is read and copied to the computer in order to generate bill. Mouse is also used to input data into computer. Mouse is a device that controls movement of the pointer (also known as cursor) on the display screen. It is a small object with a few buttons (keys) which you can roll on a hard surface. As mouse is moving on the surface, the pointer on the display screen is also moved. A mouse must have at least one button. Most of the input devices convert the data into machine readable form.
Memory and Control Unit
Once input is collected via input devices, the input is needed to be stored into the computer memory. Computer memory retains data, instructions and processed output for a while (short duration) or for a long time. There are different types of computer memories. Some computer memories are capable of remembering the content for very short duration; say till the work is in progress and continuous supply of power is ensured. Such memory is called volatile memory. Such memory forms primary storage of a computer, hence it is known as primary memory. It is also called as temporary memory or main memory. The input from different devices goes first to the main memory and will be retained into the memory electronically. The content will remain in the main memory till the computer is switched on. When computer is switched off or reset, the content will be lost. To preserve the content for a long, we need secondary or auxiliary storage. The secondary storage memory is not volatile and content can be preserved for long time. Devices that use secondary memory are called secondary storage devices. Hard disk and compact disks are the most popular secondary devices. Unlike the primary memory, the secondary storage is non-volatile, slow (in comparison with primary memory), less expensive, and large in capacity.
Working of a Typical Computer
Just as a calculator calculates, a driver drives and a painter paints, computer computes. The computing here is not restricted to only mathematical computing but to a variety of logic based tasks. One only needs to systematically design step by step clear guidelines for the task to be solved. These guidelines generally written in simple English language are called algorithm. Computer once given proper set of instructions can perform operations like generating bills, reserving tickets, printing mark-sheets, printing business reports or communicating messages. Computer can also deal with audio, video, graphs and animations besides texts and numbers.
Once the computer is given data and step by step instructions, it then performs computations and generates result or performs an action as an output. The set of data and instructions provided by a user to the computer is called an input. Computer processes this input and presents results to the user. The result is called an output. Computer can remember these data, instructions and calculated results for future use by storing the details in memory. This simple flow of working of computer is shown in figure 1.1
Following sample list presents some sample application to highlight use of computers in different areas:
- Ticket reservations
- Bank operations
- Inventory management and manufacturing support
- Entertainment such as playing games, composing music and editing movies.
- Teaching
- Financial Accounting
- Correspondence and publishing (composing newspapers, writing letters, books etc.)
- Space application
- Robotics
- Email and Chatting
- Website development etc.
The simple model of a typical computer is based on the working of computer shown in the figure 1.1. As we discussed, instructions are needed to make computers perform some actions. To obey instructions provided by the user and perform computations, a computer needs to have a mechanism to input. This mechanism is called input unit. Devices used for the input purposes are known as input devices. Typically input devices such as mouse and keyboards are used for this purpose.
Input provide through the input mechanism is stored in memory of the computer and further processed by a mechanism called processing unit or processor. Results are presented to the user through output mechanism called output unit. Typical output devices are monitor and printer. In short the input, memory, processor and output are the basic components of a typical computer.
Input Unit
The input provides a facility to enter data and instruction into the computer. Input mechanism supports many devices such as keyboard, mouse, joystick, barcode reader, universal serial bus (USB) devices, hard disk and compact disks (CDs). Different input devices take data in different forms and send it to the computer memory. Fro example, use of keyboard to enter data and instructions is very much similar to the use of a typewriter. Another way to input data is reading through barcode reader. Barcode reader is normally seen at superstore. Remember when you purchase a pack of biscuits, the shopkeeper uses a small device and presses a button on the device. With sound of a beep, the barcode printed on a tag of the biscuit pack is read and copied to the computer in order to generate bill. Mouse is also used to input data into computer. Mouse is a device that controls movement of the pointer (also known as cursor) on the display screen. It is a small object with a few buttons (keys) which you can roll on a hard surface. As mouse is moving on the surface, the pointer on the display screen is also moved. A mouse must have at least one button. Most of the input devices convert the data into machine readable form.
Memory and Control Unit
Once input is collected via input devices, the input is needed to be stored into the computer memory. Computer memory retains data, instructions and processed output for a while (short duration) or for a long time. There are different types of computer memories. Some computer memories are capable of remembering the content for very short duration; say till the work is in progress and continuous supply of power is ensured. Such memory is called volatile memory. Such memory forms primary storage of a computer, hence it is known as primary memory. It is also called as temporary memory or main memory. The input from different devices goes first to the main memory and will be retained into the memory electronically. The content will remain in the main memory till the computer is switched on. When computer is switched off or reset, the content will be lost. To preserve the content for a long, we need secondary or auxiliary storage. The secondary storage memory is not volatile and content can be preserved for long time. Devices that use secondary memory are called secondary storage devices. Hard disk and compact disks are the most popular secondary devices. Unlike the primary memory, the secondary storage is non-volatile, slow (in comparison with primary memory), less expensive, and large in capacity.
