Chapter 4

Chapter 4 : System Unit Components 

System unit is a case that contains electronic components of the computer used to process data .

Inside system unit have :

1. Drive bay
2. Power supply 
3. Sound card 
4. Video card 
5. Processor 
6. Memory 

Motherboard - Main circuit board of the system unit

Processor 

Processor also known as Central Processing Unit (CPU), interprets and carries out the basic instructions that operate a computer and contain a control unit and an arithmetic logic unit(ALU)

Have 3 different processor : Multicore processor , Dual-core processor ,  Quad-core Processor 

Control units - is a components of the processor that directs and coordinates most of the operations in the computer

Arithmetic logic unit (ALU) - Performs arithmetic , comparison , and  other  operations

Systems clock - Controls the timing of all computer operations . The pace of the systems clock is called the clock speed , and is measured in gigahertz

A processor chips generates heat that could cause the chips burn up so require a cooling systems to cool it down like Heat sinks and Liquid cooling technology .

Data representation 

Analog - signals are continuous and vary in strength and quality

Digital -  signals are in one of two states : on or off

The Binary system uses two unique digits (0 and 1)

ASCII(American standard Code For Information Interchange) is the most widely used coding scheme to represent data

How a letter is converted to binary  form and back 

• Step 1 : Press 'T' (Shift + T keys ) on the keyboard which in turn creates a special code , called scan code .
• Step 2 : The scan code for the capital letter T is sent to the system units
• Step 3 : The system unit converts the scan code for the capital letter T to its ASCII Binary code  and stores its in its memory for processing.
• Step 4 : After processing , the binary code for the capital letter T is converted to an image and display on the output 

Memory

Memory consists of electronic components that stores instructions waiting to be executed by processor ,data needed by those instructions . 

Memory size is measured in kilobytes(K) , megabytes (MB) , gigabytes (GB) , terabytes (TB)

The system unit contains two types of memory 

Volatile memory - contains will lose when power off 

Non-volatile memory - contains will not lose when power off

Three basics type of RAM

1. Dynamic RAM(DRAM)
2. Static RAM (SRAM)
3. Magnetoresistive RAM(MRAM)

RAM chips is locate on a memory module and inserted into memory slots .The amount of RAM is important and its depends on types of software you using 

Memory cache - speeds the processes of the computer because it stores frequently used instructions and data 

Flash memory - can be erased and rewritten 

Expansion slots and Adapter cards

Expansion slots is a sockets on the mother board that can hold an adapter card 

Adapter card enhances functions of a component or provides connections to peripherals like sounds card and Video card

Removable flash memory - Memory cards , USB Flash drives , and PC Cards 

Port and Connectors 

Port - peripheral attaches to or communicates with a system unit