Class 11 IP Chapter 1 Computer System Notes : CBSE Class 11 is crucial for students as it sets the groundwork for Class 12. Our Class 11 Revision Notes are here to ease the stress and help students excel. These notes are crafted by J.D Sir, align with the latest CBSE syllabus of Informatics Practices, covering all subjects concisely for effective learning.
Important Short Notes on Computer System : Code with J.D Sir
What is Computer System?
Combination of Software and Hardware together is called Computer System. A
computer is a device (hardware) that can perform operations in accordance
with a set of instructions called program (software).
Component of Computer System
Since a computer follows Input-Process-Output cycle, thus components of computer are categorized in three parts:
- Input Devices
- Central Processing Unit
- Output Devices
The basic component structure of computer is as shown below:
As shown in diagram various part of computer interact together to make the
computer work, you input data to computer by using input devices and the
CPU acts upon this data and provide output which is made available to user
by using output device.
Input devices
Input device is responsible for taking input from user and provide to computer. Some most commonly used input devices are :
- Keyboard
- Mouse
- Microphone
- Webcam
- Scanner
- Bar code reader
- Light pen
- Joystick
Output devices
Output device is responsible for providing and displaying output to user. Some most commonly used output devices are:
- Monitor- LED Monitor, LCD Monitor, CRT Monitor
-
Printer- Impact Printer (Inkjet, Dot-Matrix), Non-Impact Printer (Laser,
Inkjet)
- Plotter
- Speaker
CPU (Central Processing Unit)
CPU is control center of computer. It understands the instructions and carries out operations on the computer accordingly. It is the brain of computer and controls the activity performed by the computer.
The CPU has three components:
- ALU (Arithmetic and Logical Unit)
- MU (Memory Unit)
- CU (Control Unit)
ALU (Arithmetic and Logical Unit)
ALU is component which is responsible for all the arithmetic or logical
operation done on the data. Arithmetic operations are the basic
mathematical calculations. Logical operations are basically comparison
operation involves comparing data and determine different action to be
performed PROCESSOR.
CU (Control Unit)
The control unit is a component which controls the flow of data and
operations in a computer. It acts as a manager and instructs and
coordinates all the components of CPU to perform their respective task.
MU (Memory Unit)
Memory unit is a component which is responsible for storing all data and
information and instructions.
Memory
Memory of computer is more like a predefined working space where it
temporary keep information and data to facilitate its performance. When
the task is performed, it clears it’s memory and memory space is then
available for the next task to be performed. This memory is often called
main memory. There are two types of memory:
Primary Memory
Primary memory also known as Volatile memory that is temporary as it loses
its contents when the computer’s power is turned off. It is internal
memory that is accessed directly by the processor. Following are the
Primary memory:
- RAM: Random Access Memory is the memory that the computer
uses for storing the programs and their data while working on them. We can
either read data from the RAM or write onto it. Hence it is called
read/write memory.
-
ROM: Read Only Memory is used to store the data about the
hardware which does not required frequent updates, for example startup
programs that loads Operating System into RAM. ROM is non-volatile memory.
We can only read data from the ROM and hence called read only memory.
-
Cache Memory: Catch memory is very high speed
memory which is placed between processor and RAM to speed up the
operations of CPU. Generally it stores the copies of data frequently
accessed from RAM.
Secondary Memory
Secondary memory also known as non-volatile memory stores data and
instructions permanently for future use. It is slower than primary memory
but cannot be accessed by processor directly. Example of Secondary Memory
are :
- Hard Disk
- CD/DVD
- USB Flash Drive
- Memory Card
Memory Unit
‘Byte’ is unit of memory used to measure amount of space consumed by data
or instructions in memory.
Memory size conventions
1 Kilobyte = 1024 Bytes
1 Megabyte = 1024 KB
1 Gigabyte = 1024 MB
1 Terabyte = 1024GB
1 Petabyte = 1024TB
1 Exabyte = 1024 PB
Data Capturing
Data capturing refers to process of collecting or inputting data from
different sources. To input data different input devices can be used such
as keyboard, scanner, camera, bar code reader etc. data capturing might be
a complex process due to nonuniformity in data.
Data Storage
Data storage refers to process of storing captured data for future use.
There are many different types of storage device are available which can
be used to store data. Now a day due to rise in computers, Internet and
Technology large volume of data being produced and hence the storage
device should be of large capacity and updated regularly. to store large
amount of data, Server can be deployed or Cloud computing can also be
used.
Data Retrieval
Data Retrieval refers to accessing or fetching data from storage device as
per requirement. Due to large volume of data now a day, system must have
good quality and effective programs in order to access data at minimum
time.
Data Deletion and Recovery
Deleting data refers to erasing data from storage device. There can be
many reasons for deleting data such as system crash, accidental deletion,
and illegal deletion by hackers/mischief mongers. When data is deleted
from storage media, only the status (address entry) of data is changed and
that space is shown empty to user without deleting data actually.
Data recovery is process of accessing deleted, lost or corrupted data from
storage device. Deleted data can only be recovered when memory space of
deleted data have not been overwritten with new data.
Software
Software is set of programs that instruct hardware to what to and how to
do. It makes hardware functional to achieve a common objective. Some
example of software is Window10, Macintosh, MySQL, MS Word, Excel, Games
etc.
Types of software
There are two types of software:
- System software
- Application software
System Software
System software manages computer system. It is software that control and
coordinate all internal activities of a computer system.
System software can be categorized as
- Operating System
- Utility Software
- Device Driver
Operating System
Operating System acts as an interface between user and machine. It is set
of programs that –
- Manages hardware resources
- Manage memory
- Display result in monitor
- Control all hardware component attached to computer system
- Read data through input devices
Examples of Operating System are Window10, Window8, Macintosh, Ubuntu, DOS
etc.
Utility software
It is system software that helps you to configure and optimize and
maintain a computer. Examples of utility software are- Disk Cleaner, File
Backup Utility, Antivirus, Firewall, Disk Defragmenter etc.
Device Driver
Device driver is software which controls a particular type of hardware
attached with a computer. It acts as an interpreter between particular
hardware and computer system.
Realted Queries : Class 11 IP Computer System Short Notes, Information Practices Short Notes, CBSE Class 11 Information Practices Important Notes for Exam
