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Informatics Practices · Class 11 Optional

Ch 1Computer System — Class 11 Informatics Practices, concept-first.

Every computing device, from the phone in your pocket to a huge machine running a website, does the same three things: it takes in data, works on that data, and hands back a result. A computer is an electronic device that can be programmed to accept data (the input), process it, and generate a result (the output).

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Key concepts

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Chapter contents

The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.

1.1

Introduction to Computer System

Every computing device, from the phone in your pocket to a huge machine running a website, does the same three things: it takes in data, works on that data, and hands back a result.

1.1.1

Central Processing Unit (CPU)

If the computer system has a brain, it is the CPU. The Central Processing Unit is the electronic circuitry of a computer that carries out the actual processing, and for this reason it is usually refer…

1.1.2

Input Devices

A computer can process only what reaches it, and it understands only digital signals. Input devices are the devices through which control signals are sent to a computer.

1.1.3

Output Devices

Processing is invisible until the computer shows us the result. An output device is a device that receives data from a computer system for display, physical production, and similar purposes.

1.2

Evolution of Computer

The road from a simple calculating aid to the modern data processor was travelled in a remarkably short span of time.

1.3

Computer Memory

A computer can process nothing until the data to be worked on and the instructions describing what to do with it are held somewhere inside the machine.

1.3.1

Units of Memory

Everything a computer stores or processes — numbers, text, pictures, programs — is ultimately represented in binary.

1.3.2

Types of Memory

Human beings remember a great deal, and recall those memories to make decisions and take action. Yet no one relies on memory alone — we write notes and keep important information for the long term in…

1.3.3

Data Capturing, Storage, and Retrieval

2 Q

Processing data is never a single act — it is a cycle. Data must first be brought into the system in digital form, then kept safely in a file or database, and finally fetched back out whenever it is n…

1.3.4

Data Deletion and Recovery

2 Q

Digital data can vanish far more easily than it was created — a storage device can crash, a user can erase a file by mistake, or a hacker or a piece of malware can wipe it out deliberately.

1.4

Software

Everything studied so far — the CPU, memory, input and output devices — is hardware: the physical machinery of a computer system. But hardware on its own does nothing.

1.4.1

Need of Software

A computer's hardware, however sophisticated, cannot be spoken to directly. A human user has no way of instructing a processor or a printer in the raw electrical terms those devices understand.

1.4.2

System Software

Some software exists not to serve any one task of the user, but to keep the computer itself running. The software that provides the basic functionality to operate a computer, by interacting directly w…

1.4.3

Application Software

System software makes the computer operational — but an operational computer is not yet a useful one for any particular person.

1.4.4

Proprietary or Free and Open Source Software

Beyond what a piece of software does lies the question of the terms on which it reaches you: can you use it freely, can you see and change its source code, or must you buy it from a copyright holder?…

Summary

- A computing device, also referred to as a computer, processes the input data as per given instructions to generate the desired output.

Exercises

Think and Reflect