3 lessons you must know about computer

Computer is a very important part of our daily life now a days. So we all need to know some basic knowledge about computer. Computer is used to called calculator machine but now it can reduce a lot of human effort and work all alone and do multiple task without any help and in a very short time. As before we are going to start to post more computer lessons and basics fast of all you need to learn how a computer works. These are the basic three examples listed below how a computer works ?

1.Data representation
2.Data processing
3.Components affecting speed

How computer represent data ?

Number systems
- A manner of counting
- Several different number systems exist
Decimal number system
- Used by humans to count
- Contains ten distinct digits
Digits combine to make larger numbers.

Binary number system
- Used by computers to count
- Two distinct digits , 0 and 1
- 0 and 1 combine to make numbers

Bits and bytes
- Binary numbers are made of bits
- Bit represents a switch
- A byte is 8 bits
- Byte represents one character

Text Codes
- Converts letters into binary
- Standard codes necessary for data transfer
- ASCII
  - American English symbols
- Extended ASCII
  - Graphics and other symbols
- Unicode
  - All languages on the planet

How a computer Process data ?

The CPU
- Central Processing Unit
- Brain of computer
- Control unit
  - controls resources in computer
- Arithmetic logic unit
  - simple math operations
  - registers

Machine cycles
- Steps by CPU to process data
- Instruction cycle
  - CPU gets the instruction
- Execution cycle
  - CPU performs the instruction
- Multitasking allows multiple instructions

Memory
- Stores open programs and data
- Small chips on the motherborad
- More memory makes a computer faster

Nonvolatile memory
- Holds data when power is off
- Read only memory (ROM)
- Basic Input Output System (BIOS)
- Power On Self Test (POST)

Flash Memory
- Data is stored using physical switches
- Special form of nonvolatile memory
- Camera cards , USB key chains

Volatile memory
- Requires power to hold data
- Random Access Memory (RAM)
- Data in RAM has an address
- CPU reads data using the address
- CPU can read any address

Components Affecting Speed

Registers
- Numbers of bits processor can handle
- Larger indicates more powerful computer
- Increase by purchasing new CPU

Virtual RAM
- Computer is out of actual RAM
- File that emulates RAM
- Computer swaps data to virtual RAM
  - Least recently used data is moved

The computer internal clock
- Quartz crystal
- Every tick causes a cycle
- Speeds measured in Hertz (HZ)
  - Modern machines use Giga Hertz (GHz)

The bus
- Electronic pathway between components
- System bus connects CPU and RAM
- Bus width is measured in bits
- Speed is tied to the clock

Peripheral control interface (PCI)
- Connects modems and sound cards
- Found in most modern computers

External bus standards
- Industry Standard Architecture (ISA)
- Local bus
- Penpheral control interface (PCI)
- Accelerated graphics port (AGP)
- Universal serial bus (USB)
- IEEE 1394 (fireWire)
- PC Card

Accelerated Graphics Port (AGP)
- Connects video card to motherboard
- extremely fast bus
- Found in all modern computers

Universal Serial Bus (USB)
- Connects external devices
- Hot swappable [ device can be attached or detached without reboot]
- Allows up to 127 devices
- Cameras , printers and scanners , mouse , keyboard and others.

PC Card
- Used on laptops
- Hot swappable
- Devices are the size of a credit card

Cache Memory
- Very fast memory
- Holds common or recently used data
- Speeds up computer processing
- Most computers have several caches
- L1 holds recently used data
- L2 holds upcoming data
- L3 holds possible upcoming data