COMPU. CHAPTER 1

DISCLAIMER : The Informtion I'm Giving in this chapter is Correct to the Best of My Knowledge...Any Mistakes That May Have Crept-in Are to Be Tolerated or to be informed to the author i mean the administrator.

: NOTE :

THIS SOCIAL SERVICE WILL BE CONTINUED SUBJECT TO CONDITION I GET ATLEAST 5 RESPONSES FROM 5 DIFFERENT PEOPLE...

HI,

From today we will start a virtual classroom for the subject computers.....ok?

Me, Revappa, will go on giving/presenting u the details of the material i've, for Computer Subject...

Let's Directly Jump to The Syllabus....

CHAPTER 1 - COMPUTER CONCEPTS

A Computer is A An Electronic Device That Is Used for information processing. It Accepts The Data And Instructions, Stores it in its memory, processes & Gives the results to the user.

Find More @ : http://en.wikipedia.org/wiki/Computer

Parts of A Computer :

Before Jumping on the Parts PART :
Let's Know The Functional Units Of A Computer :

1.Input Unit -

• It's An External Device Connected to The CPU.
• It's Used To Feed Data & instructions
• Commonly used iNPUT UNITs are

• 
  

keyBoard

Mouse

Joystick

LightPen

trackball

Optical scanner

Digitize

Voice input ( Microphone)

Disks (CDs/DVDs)

• 
  

2.system Unit -

• Once d Data & Instructions r Recieved They r Stored & Processed In This Unit
• It has 2 Parts : CPU & Memory Unit

1.CPU

• Central Processing Unit
• Heart & Brain of Computer
• It has 2 Parts :
  

1. Control Unit
   
2. Arithmetic & Logic Unit

Control Unit Acts As A Supervisor. It Sends CONTROL & TIMING SIGNALS to various units to coordinate for the specific operation. It's Duties Are

• fetching Data & Instruction from The Main Memory
• Interpretting These Instructions
• Controlling the TRANSFER of data & information TO & FROM the main memory.
• Controlling Input & OutPut Devices.
• The Overall supervision of Computer System.

ALU - Arithmetic & Logic Unit consists of An electronic Circuitrywhich performs A basic Operation Such As Addition, Subtraction, Multiplication & division. And the logical circuitry performs the logical operations which result in the TRU or FALSE Results.

To Put The Functioning of These Two Units in Terms of Analogy :

ALU acts as an ACCOUNTANT while the CU acts as A PERSONAL SECRETARY.

2. Memory Unit :

• This is A Storage Device
• The Memory of A Computer is Measured in terms of BITS, BYTES & WORDS.

1. a BIT is a binary digit & is either a 0(zero) or 1(one).
2. a BYTE is a basic unit of memory & is defined as a sequence of 8 BITS.
3. a WORD can be defined as a sequence of 16 BITS or 2 BYTES.

and

• Computer Memory is classified into :

1. Main Memory
2. Secondary Memory
3. Cache Memory

Main memory is A Temporary Memory Because the data & instructions stored here are erased when the power goes off. This is also referred to as primary memory ( because any DATA or Instruction Given, will be store din this memory ). It's a Semiconductor Memory. It consists of RAM & ROM main memories.

• RAM ( Random Access Memory )
  
• ROM ( Read Only Memory )
  
• PROM ( Programmable ROM )
  
• EPROM ( Erasable PROM )
  
• EEPROM ( Electrcally EPROM )
  

Secondary Memory is a Permanent Memory. It is also called BACKUP MEMORY or an AUXILLORY MEMORY. It's made up of magnetic material/ flash material.

• Magnetic Tape
• Magnetic Disk
• Magnetic Drum
• Optical Disk
• Flash memory

Cache memory is The High Speed memory & Placed between The CPU & the Main memory. The Data & instructions Stored in In It Are Accessed At A Higher speed As Compared to The MAin memory. It stores Data & Instructions That R Currently To Be Executed. Access Time Allotted is 15-25 nano seconds compared to the main memory time of 80 ns.

Find More @ : http://en.wikipedia.org/wiki/Computer_data_storage

3.Output Unit -

• This is Used to Display the Results obtained after the execution of a program.
• Whenever the user wants output from the computer, the control unit sends signal to this unit to BE READY to accept the data from memory & to Display it.
• Commonly used Display Unit is MONITOR. & Some others Are :

Printer

Plotter

Plasma Diplay Panel

LCD / TFT / LED Displays

Voice Output ( speaker)

Disks ( CDs/DVDs)

ok...Back To The Syllabus.

: Parts of A Computer, Peripherals & Their Function :

STORAGE : STORAGE : STORAGE : STORAGE : STORAGE

1. RAM / ROM

2. HARD DISK

[ NEW IN THE MARKET is SOLID STATE DRIVE replacing the HDD]

3. EXTERNAL STORAGE

[ FLOPPYs /
CDs /
DVDs /
BLURAYs /
PENDRIVEs /
Portable HARD DISKs /
MEMORYCARDS... ]

PROCESSOR :PROCESSOR :PROCESSOR :PROCESSOR :

Find More @ :

http://en.wikipedia.org/wiki/Central_processing_unit

DISPLAY :DISPLAY :DISPLAY :DISPLAY :DISPLAY :

CRT

TFT / LCD

LED

MONITOR TV

TOUCHSCREEN

MOUSE :MOUSE :MOUSE :MOUSE :MOUSE :MOUSE :MOUSE

SCROLLBALL

OPTICAL

PORTS :PORTS :PORTS :PORTS :PORTS :PORTS :PORTS

PORT

CD DRIVE :CD DRIVE :CD DRIVE :CD DRIVE :CD DRIVE

CD DRIVE

PRINTER :PRINTER :PRINTER :PRINTER :PRINTER :

PRINTER

SCANNER :SCANNER :SCANNER :SCANNER :SCANNER :

SCANNER

.....To Be Continued.