Computer Hardware & Processing Inside the Box

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September 16, 2010

Why does computer technology change so quicklyMoore’s lawTechnology changes every 18 months

The Motherboard

• CPU• RAM• Expansion

cards and slots

• Built-in components

The CPU - Central Processing Unit

• Referred to as the “brains” of the computer

• Controls all functions of the computer

• Processes all commands and instructions

• Can perform billions of tasks per second

How fast is a CPU?

• Speed– Megahertz (MHz)– Gigahertz (GHz)– System clock

• Cores– Single– Dual– Quad

Parts of the CPU

The Machine Cycle

Computer Memory

• RAM – Random Access Memory• ROM – Read Only Memory• Cache Memory – very fast memory used by

the CPU

ROM

• Hard wired at the factory

• Cannot be changed

• Contains the instructions the computer needs to start

RAM

• Volatile – No power, no data• All programs and files must be loaded into

RAM to be used• RAM connected to the CPU• Primary storage

How much RAM do you need?

Application Minimum RAM Required

Windows 7 1000 MB

Microsoft Office Professional 2007 256 MB

Internet Explorer 8 128 MB

iTunes 256 MB

Adobe Photoshop Elements 512 MB

Total RAM required to run all programs simultaneously 2,152 MB or 2.15 GB

It depends on what programs you run

Operating system is always in RAM

Virtual Memory

• Space reserved on the hard drive • Computer act like it has more memory than it

really has• Programs swapped between real memory and

virtual memory as needed• Thrashing – computer spends too much time

swapping between real and virtual memory

Cache Memory & Registers

• Very fast memory• On the CPU chip or

in very close proximity

• Holds processors immediate results

• Holds frequently used instructions

Device/Memory/Storage HierarchyThe higher in the hierarchy, the faster and more expensive memory is

Expansion Slots

• Adds versatility and expandability to the system

Video Cards

• Process binary data into images• Contain memory known as video memory• Control the number of colors a monitor can

display (bit depth)– Standard VGA– True color

Graphics Processing Unit

• Performs the same work as a CPU• Specialized to handle

– 3D graphics– Image and video processing

• CPUs perform better with a GPU handling graphics computation.

Audio Processing

• Sound cards– Attach to

motherboard– Process digital data

into sounds– 3D sound cards– Surround sound– Allow you to connect

audio devices

Bus

• Move bits between different areas on the motherboard

• 32 bit• 64 bit

Ports

• Allow peripheral devices to be plugged in

• On both front and back of desktop computers– USB– Ethernet– Firewire