Machine Cycle

1. Machine Cycle • The 4 basic operations a processor repeats, for every instruction. • The 4 basic operations: • Fetching • Decoding • Executing • Storing (depends on instruction) • In some computers, the processor completes 1 machine cycle before beginning the next instruction. • In modern computers the processor can have multiple machine cycles at one time.

2. Registers • High speed storage locations that temporarily hold data and instructions. • They are not part of the memory. • Processors have many different types of registers. • Each register has a different function. • Functions include: • Location where instruction was fetched • Storing while it is decoded • Storing while instructions are computed • Storing results of a calculation

3. The System Clock • Controls the timing of all computer operations. • Generates regular electronic pulses, or ticks, that set the operating pace of components of the system unit cycle. • Each tic equates to a clock cycle. • Pace of system clock (clock speed) is measured by the number of ticks per second. • Faster the clock speed the more instructions a processor can execute.

4. The System Clock (cont.) Older computer Processor Current PC Processor Uses one or more clock cycles to execute each instruction. Execute more than one instruction per clock cycle. Have clock speeds in the gigahertz range. One gigahertz equals one billion ticks per second.

5. Comparison of Personal Computer Processors • Leading processor chip manufactures are Intel, AMD, Transmeta, IBM, and Motorola • The greater number of transistors, the more complex and powerful the chip. • AMD and Transmeta both make Intel–compatible processors. • Intel-compatible processors are similar in design, function and power, but are cheaper • Each company has a model name or number to idenitfy their processor. • Some common model names are Pentium, Xeon, and Itanium.

6. Heat sinks, Heat Pipes, and Liquid Cooling • Heat sink-a small ceramic, or metal component with fins that absorb and disperses heat produced by electrical components. • Heat pipe- same as a heat sink only smaller, generally used in notebooks. • Liquid cooling technology- uses a continuous flow of fluids such as water and glycol, that transfers the heated fluid away from the processor to a radiator-type grill, where it is cool, and then returns to the processor.

7. Parallel Processing • Method that uses multiple processor simultaneously to execute a single program or task. • They divide a single problem into portions so different parts of the problem can be worked on simultaneously. • Parallel Processing requires special software that can separate the problem then fix it. • Some PCs use dual-core processors or multi-core processor chips • Supercomputers use parallel processing for weather forecasting.

8. Expansion Slots and Cards • Expansion Slots-A Socket found on the motherboard that can hold the adapter card. • An Expansion Card- is a circuit board that enhances functions of a component of the system unit and/or provides connections to peripherals. • Other names for an Expansion Card is adapter card, expansion board, adapter, interface card, add-in, and add-on.

9. PC Cards • Thin device that adds memory, storage, sound, fax/modem, network, and other capabilities to mobile computers. • Also used in other electronics such as a digital camera. • Many are like a flash memory card.

10. Ports • The point at which a peripheral attaches to or communicates with a system unit. • Ports are found on the back of the system unit or the front of newer personal computers. • Serial Ports transfers one bit at a time and have slower transmission rates.

11. Ports • Parallel Ports transfers more than one bit at a time. • USB Ports used for mouse, printer, camera, scanner, speaker, etc. • FireWire Ports similar to USB but connects multiple types of data that require a faster speed.