IT tools and Network basics✍🏻

 What is computer?

Computer is a very versatile electronic machine man has ever created , computers have made a great impact on our everyday life.

Their presence is felt in almost everywhere of life be it home, school, college,office, industry, hospital,bank,retail stores, railways, reasearch and design organization etc.

What do computers do?

Input,process, output & store data. 

Data and Information:-

• All computer processing requires data,which is a collection of row.Facts,figures and symbols,such as numbers,words,images,video,and sound,given to the computer during the input phase.
• Computer manipulate data to create information.
• Information is data that is organised, meaningful,and useful.

Note:-Data is noting,data is only called as information.

Types of computers:-

1.Analog computer:-

Analog computers handle or process information which is of a physical nature,as for example of temperature, speedometer ,pressure,etc.

2.Digital computer:-

Digital computers process information which is an essentially in a binary or two-state form,namely zero and one.

• Digital computers is designed to process digital data and perform logical operators at a very high speed.example of laptop and smartphone.
• When talking about computers,we mostly refer to the digital type of electronic machines.These are based on the measuring of analog or equivalent physical values.

Note:-processor chip understood by binary language.

Types of digital computers:-

1.Micro-computer

2.Mini-computer

3.Mainframe

4.Super-computer

1.Micro-computer:-

• Can be classified into:-
• Desktop pcs
• Sits on desks,rarely moved,large and bulky.
• Memory capacity,graphics capacity and software availability very from one computer to another used both for business and home applications .

Micro-computer model-

• Desktop 
• Laptop 
• Notebook 
• Subnotebook 
• Palmtop

Advantages:-

• Small size
• Low cost
• Portability 
• Low computing power
• Commonly used for personal applications.

Disadvantages:-

• Low processing speed 

Micro-computer:-

Portable pcs -

• Can be moved easily from place to place.
• Weight may varies.
• Small pcs are popular known as laptop.
• Widely used by students, scientist,reporters,etc.

2.Mini-computer:-

Mini computers are smaller, less expensive and less powerful than mainframe computer and super computer,but are more costly & more than micro-computer.

• Medium sized computers 
• Also called the minis
• E.g:-IBM36,HP9000,etc.
• Computing power lies between micro-computer and mainframe computer.

Characteristics:-

• Bigger size than pcs
• Expensive than pcs
• Multi-user
• Difficult to use
• More computing power than pcs
• Used by medium sized business organizations colleges, libraries and banks, institute,etc.

Advantages:-

• Cater to multiple users.
• Lower costs than mainframes.

Disadvantages:-

• Bulky
• Large

3.Mainframe:-

• Known as enterprise servers.
• Occupies entire rooms or floors.
• Used for centralized computing.
• Serve distributed users and small servers in a computing network.
• Large ,fast and expensive computer.
• Cost millions of dollars.
• Eg:- IBM3091, ICL39,etc

Characteristics:-

• Bigger in size than mini-computers
• Very expensive 
• Support a few hundred users simultaneously (multi-users).
• Different to use
• More computing power than mini-computer.
• Have to be kept in a special air-conditioned room.
• Used in big business organization and government departments.

Advantages:-

• Supports many users and instructions.
• Large memory 

Disadvantages:-

• Huge size
• Expensive 

4.Super-computer:-These are the largest, fastest,most powerful and most expensive computers, often used for scientific research, wheather,and quantum mechanics.

• Fastest and expensive 
• Used by application for molecular chemistry, nuclear research, wheather reports,and advanced physics.
• Consists of several computers that work in parallel as a single system.

Memory:-

Found on the motherboard 

# Short-team

Random Access Memory (RAM)

# Long-team

Read Only Memory (ROM)

#Random Access Memory (RAM):-

Ram is a read/write memory. Information can be written into and read from a RAM. It is a volatile memory. It retains the stored information as long as it is supplied with power supply.When power supply is switched off or interrupted,the stored information in the RAM is lost. RAMs of various capacities are available.

For example:-256MB,512MB,and so on.

Types of RAM:-

1.Static RAM

2.Dynamic RAM

  

Read Only Memory (ROM):-

Rom is permanent type memory. It's contents are not lost when power supply is switched off. The user cannot write into a ROM.
It's contents are written into at manufacturing time.Roms store permanent programs and other types of data which are needed by the computer to execute user program.

Types of ROM:-

1.PROM (programmable ROM)

2.EPROM (Erasable PROM)

3.EEPROM(electronically erasable PROM).