What is the necessity of Network: Network is use to
· File sharing
· Print sharing
· Fax sharing
· Remote Access
· Shared databases
· Fault tolerance
· Internet access and security
· Communication and collaboration
LAN (Local Area Network) : Physically link two or more computers within a small area is known as LAN. A high speed data transfer network that supports 1 MBPS to 30 Mbps or more.
Wireless LAN (WLAN): Wireless Network don no require and physical media or cables for data transmission. (Use Radio Freq. Tech.)
MAN (Metropolitan Area Network): Collection of LAN based on Fiber Optic transmission technology that supports 10 Mbps transferring of data between sites. They are between LAN & WAN.
WAN (Wide Area Network): Digital communication system that cover Large geographical Area, which is controlled by public authority (Govt.), use telephone services and satellite for transmission and may also enable LAN's to communicate with each other. It operates at lower link speeds of about 1 Mbps
Hardware V/S Software
Refers to components that
Constitutes computer system.
Refers to means of controlling the computer equipment.
It refers to physical, visible
Components of a computer.
If refers to invisible components of a computer.
It is made up of input devices,
output devices, C.P.U., storage
devices, communication devices etc.
Software is made up of data and instructions.
Hardware is produced by
Hardware manufacturers. Eg.
IBM, INTEL, HCL, WIPRO, HP,
Software like WINDOWS are
Manufactured by big software companies like MICROSOFT. Some readymade application Software like "TALLY, Ex etc. are manufactured by Software companies like TCS, Infosys etc. Other application Software may be prepared by individual programmers and end users.
ROM V/S RAM
Read Only Memory.
Random Access Memory
Contents of ROM can be read and used but can't be corrected or erased.
Contents of RAM can be read, used, corrected or erased.
ROM is not volatile i.e. the contents are not lost when power is switched off.
It is volatile i.e. its contents are lost when the power is switched off.
Very small in size.
Very large in size.
Contains important instructions which are needed to activate the system at the time of starting or booting.
It contains data and instructions of the applications which are under process.
It is a permanent storage which
contains same instructions at all
It is a temporary storage which gets different sets of data and programmes at different times, depending on the application being processed.
ROM instructions are loaded by
RAM instructions are loaded by the user.
Programmers and machine use RAM.
Only machines use ROM
Added to the system as a part and parcel of the Circuitry.
Added to the system as a supplementary to primary storage.
It is electronic in nature and is usually
supplied in the form of chips.
Magnetic or optical in nature and supplied in the form of tapes and disks.
Provides Random access to data.
Provides Sequential / direct access to data.
Volatile i.e. its contents are lost when power is lost.
Non volatile i.e. it does not lose its contents even when the power is lost.
Fast access to data.
Slow access to data.
Generally a computer consists of few MB's of memory.
Generally a computer consists of few GB's of
1) Meaning: It is an important type of SW which is essential for computer system to be used by the user. Used to improve the performance and maximum utilization of system resources.
2) Examples: Operating system, Computer languages, Compilation SW, Utility
programmes, Library functions,
Diagnostic SW etc.
3) Who produce? May be prepared by large SW companies like MICROSOFT. Some may also be written by system programmers.
4) Updating: Once prepared doesn't change frequently except for new additions or versions.
5) Knowledge of Hardware: Detailed knowledge of hardware is required.
6) HW Independence: System software varies from computer to computer.
It is an important type of software which are created to achieve the end users or applications of the computer system. Used to improve the speed and quality of business activity.
Software for stores accounting, Financial accounting, Invoicing SW, Payroll programmes etc.
Application SW in the form of readymade application packages may be produced by SW companies. Tailor made application SW may also be written by programmers or end-users.
Goes through more frequent changes whenever policies and procedures relating to the applications are changed or when application programmes need to be improved for better performance.
This requires detailed knowledge of
Application software varies from
Organization to organization.
Local Area Network (LAN)
1. Spread/ Coverage: A LAN is restricted to a limited geographical coverage of few kilometres.
2. Data transmission errors: Fewer data transmission errors occur in case of LAN because the distance covered in less.
3. Data transmission speed: Data transmission speed is much higher in LAN than in WAN. Typical transmission speeds in
LAN'S are 0.1 to 10 MBPS.
4. Communication Mode: Communication may take place just by a way of direct cabling.
5. Security: Security is not that much important because the network runs within the organisation
Wide Area Network (WAN)
WAN spreads over greater distance and may operate nationwide or even worldwide
When compared to LAN, error rate is more because the distance covered is more.
In a WAN the data transmission speed ranges from 180 to 9600 Bits per second.
Communication takes place by way of telecommunication cables, satellites or microwaves.
Security is very important because the network has to run outside organisation also.