1. Introduction Computer Hardware Jess Role @UEAB 2006
The CPU
Introduction Computer Hardware Jess 2006

2. Central Processing Unit
What is a CPU?
What is the central processing unit (CPU)?
Interprets and carries out the basic instructions that operate a computer
Most devices communicate with the CPU in order to carry out a task
Also called the processor
Introduction Computer Hardware Jess 2006

3. Introduction Computer Hardware Jess Role @UEAB 2006
Basic CPU Overview
Introduction Computer Hardware Jess 2006

4. Introduction Computer Hardware Jess Role @UEAB 2006
Example of Triple
Bus Architecture
Introduction Computer Hardware Jess 2006

5. Introduction Computer Hardware Jess Role @UEAB 2006

6. Introduction Computer Hardware Jess Role @UEAB 2006

7. Central Processing Unit
What is a personal computer processor?
The single processor chip found in personal computers
Sometimes called a microprocessor
Processors identified by
Manufacturer
Model name or model number
Athlon™
Pentium® 4
Celeron™
Duron™
Introduction Computer Hardware Jess 2006

8. Introduction Computer Hardware Jess Role @UEAB 2006

9. Introduction Computer Hardware Jess Role @UEAB 2006

10. Motherboards / Chipsets / Sockets
In charge of:
Memory Controller
EIDE Controller
PCI Bridge
Real Time Clock
DMA Controller
IRDA Controller
Keyboard
Mouse
Secondary Cache
Low-Power CMOS SRAM
Introduction Computer Hardware Jess 2006

11. Central Processing Unit
What are the components of the central processing unit (CPU )?
CPU
Control Unit
Arithmetic/ Logic Unit (ALU)
Introduction Computer Hardware Jess 2006

12. Central Processing Unit
What is the control unit?
A component of the CPU that directs and coordinates most of the operations in the computer
CPU
Arithmetic/ Logic Unit (ALU)
The control unit repeats a set of four basic operations:
Control Unit
Control Unit
Fetch – obtain a program instruction or data item from memory
Decode - translate the instruction into commands
Execute - carry out the command
Store - write the result to memory
Introduction Computer Hardware Jess 2006

13. Central Processing Unit
What is a machine cycle?
Together the four operations of the CPU comprise a machine cycle
Also called an instruction cycle
Instruction time (i-time) - time it takes to fetch and decode
i-time
Execution time (e-time) – time it takes to execute and store
e-time
Introduction Computer Hardware Jess 2006

14. Central Processing Unit
What is a machine cycle?
Together the four operations of the CPU comprise a machine cycle
A student enters a math problem into the memory of the computer
Step 1: The control unit fetches the math problem from memory
Step 2: The control unit decodes the math problem and sends it to the ALU
Step 4: The results of the math problem are stored in memory
The result in memory displays on the screen of the monitor
Step 3: The ALU executes the math problem
Introduction Computer Hardware Jess 2006

15. Central Processing Unit
What is the arithmetic/logic unit (ALU)?
Component of the CPU
Performs arithmetic, comparison, and logical operations
Performs the execution part of the machine cycle
CPU
Control Unit
.and.
.not.
.or.
Arithmetic/ Logic Unit (ALU)
Introduction Computer Hardware Jess 2006

16. Central Processing Unit
What is the system clock?
Synchronizes all computer operations
Each tick is a clock cycle
Faster clock speed means the CPU can execute more instructions each second
MHz - one million ticks of the system clock
GHz – one billion ticks of the system clock
Clock speed (clock rate) measured in megahertz (MHz) and gigahertz (GHz)
Introduction Computer Hardware Jess 2006

17. Introduction Computer Hardware Jess Role @UEAB 2006
Single Bus
Slow Performance
Introduction Computer Hardware Jess 2006

18. Introduction Computer Hardware Jess Role @UEAB 2006
CPU Sockets and slots
Socket 4 & 5
Socket 7
Socket 8
Slot 1
Slot A
Introduction Computer Hardware Jess 2006

19. Introduction Computer Hardware Jess Role @UEAB 2006
Review Questions
Introduction Computer Hardware Jess 2006