1. Computer Hardware The ProcessingUnit

2. The Computer System CommunicationDevices Processing Unit InputDevices OutputDevices StorageDevices

3. The Processing Unit • The main part of a microcomputer is called the System Unit • Most of the processing hardware is on the motherboard

4. The Processing Unit • The motherboard is the main circuit board in a computer A circuit board is a sheet of fiberglass on which electronic components are soldered These components are connected with traces of copper printed on the surface

5. The Motherboard FiveMain MotherboardComponents

6. The CPU The Central Processing Unit has 3 parts

7. The Control Unit The Control Unit • Regulates the flow of information • Monitors all operations performed by the system • Runs Programs: • Fetches program instructions from memory • Increments the Program Counter • Decodes the instruction • Executes the instruction • Writes results to memory

8. The ALU The Arithmetic and Logic Unit • Performs all calculations (+, - ,*, /) • Returns the result of simple logic decisions ( isx > y true or false?) • Calculations can be accelerated by a Floating Point Unit (FPU)

9. Registers • Registers • A small amount of high-speed memory on the CPU • Registers hold the current program instruction and data • Very fast but also expensive

10. The Chipset • A chipset is a group of ICs (Integrated Circuits or computer chips) that are designed to support the CPU. • On most PC motherboards the chipset has two microprocessors often called the Northbridge and the Southbridge.

11. The Chipset The Northbridge chip links the CPU to high-speed components like main memory and video controllers.

12. The Chipset The Southbridge chip then links to lower-speed peripheral devices through connections like PCI or PCI-Express. The Southbridge may also have built-in Ethernet (networking), USB or audio device support

13. In computers, a bus is a set of connections (wires) that is shared by multiple hardware components in order to communicate. The System Bus • A general term for the bus on a motherboard that connects the CPU to all the other components. Also called a local bus. Bus SystemBus

14. The main bus between the CPU and main memory typically through the Northbridge. The System Bus • A common type of local bus that is used to connect the Southbridge chip to peripheral devices such as network expansion cards. Frontside Bus PCIBus

15. Main Memory-1 • Inside the CPU is a small amount of high-speed, expensive computer memory called registers. • The registers are used for storing data currently being processed in the CPU

16. Main Memory-2 • Most data is stored in Main Memory. • There are two types of Main Memory: RAM & ROM

17. Main Memory-3 • Between Main Memory and the CPU is a buffer or temporary storage called cache (pronounced like cash) • Cache memory stores data so that future requests for that data from the CPU can be served faster.

18. Main Memory-4

19. The System Clock • On the motherboard is a component that generates a clock signal • This is a timing signal that synchronizes all data transfer in a computer system. • The CPU also executes instructions at a speed set by the clock signal

20. The System Clock • Clock rates are measured in hertz (cycles per second) • Household AC current alternates at 60 Hertz • 1 megahertz (MHz)= 1 million hertz • 1 gigahertz (GHz)= 1 billion hertz German physicist Heinrich Hertzmade important scientific contributions to the study of electromagnetism.

21. The Motherboard Ports ExpansionSlots Northbridge CPU Southbridge RAM ROM (BIOS)

22. A Motherboard