CHAPTER 4 INFORMATION

By Tyler Williams and Jake Eichorn

The System UnitThe system unit is a case that contains electronic components of the computer used to process data.System units come in various shapes and sizes and are located anywhere depending on the design of the computer

The Arithmetic Logic Unit

Also know as the ALU. A part of the processor that performs

arithmetic, comparison, and other operations.

Arithmetic operations include basic calculations such as addition, subtraction, multiplication, and division.

Comparison operations involve comparing one data item with another to determine weather the first item is greater than, equal to, or less than the other item.

The MotherboardAlso known as the system boardIt is the main circuit board of the system unit. Many things such as a adapter cards, processing chips and memory cards are attached to the motherboard.

Machine Cycle

The four basic operation that a processor repeats which comprise a machine cycle are (1) fetching (2) decoding (3) executing (4) storing.

Machine Cycle

Fetching is the process of obtaining a program instruction or data item from memory.

Decoding is the process of translating the instruction into signals the computer can execute.

Executing in the process of carrying out the commands.

Storing is the process of writing the results to memory (not to a storage medium).

ProcessorAlso known as the CPU (Central Processing Unit), interpreters and carries out the basic instructions that operate a computer.On large computers, the various functions performed by the processor extend over many separate chips and often multiple circuit boards.

The Control UnitThe control unit is the component of the processor that directs and coordinates most of the operations in the computer. It interprets each instruction issued by a program and then initiates the appropriate action to carry out the instructions.

Registers

Are small high-speed storage locations inside a processor that temporarily hold data and instructions.

Registers are part of the processor, not part of memory or a permanent storage device.

Buying a Personal Computer

If you believe it is time for a new computer, the processor you select should depend on how you plan to use your computer. If you plan to buy a computer for just entertainment and games you may want to consider using Intel’s Viiv Technology.

The System Clock

It is a small quartz crystal circuit that the processor relies on to control the timing of all computer operations.

The pace of the system clock, called the clock speed, is measured by the number of ticks per second. Most computer processors now have clock speeds in the gigahertz range. Giga means billion and a hertz is one cycle per second so a computer with a clock speed of 3.8 GHz has 3.8 billion clock cycles in one second.

Heat Sinks, Heat Pipes and Liquid CoolingComputers can generate lots of heat inside of it. Even though the computer’s main fan operates airflow, today’s processors require more additional cooling. A heat sink is a small ceramic component with fans on it surface that absorbs and dispenses heat produced by electrical components such as a processor. A heat pipe cools the processors in notebook computers. Liquid Cooling Technology uses a continuous flow of fluids, such as water and glycol, in a process that transfers the heat fluid away from the processor to a radiator-type grill, which cools the liquid, and then returns the cooled fluid to the processor.

Comparison of Personal Computer Processors

Today the leading processor chip manufacturers for personal computers are Intel, AMD, Transmeta, IBM, and Motorola.

You can compare processor chips by the clock speed and number of transistors. The more transistors the more complex and powerful the chip.

Parallel Processing

Parallel processing is a method that uses multiple processors simultaneously to execute a single program or task. Parallel processing divides a single problem into portions so that multiple processors work on their assigned portion of the problem at the same time.

Expansion Slots

An expansion slot is a socket on the motherboard that can hold an adapter card.

Expansion Cards

Also known as an Adapter cardIt is a circuit board that enhances functions of a component of the system unit and/or provides connections to peripherals.

PC Card

A PC card is a thin, credit card-sized device that adds memory, storage, sound, fax/modem, network, and other capabilities to mobile computers. Because of their small size and versatility, some consumer electronics such as digital cameras use PC cards.

Ports

A port is the point at which a peripheral attaches to or receive information from the computer.

Special Purpose Ports

The four special purpose ports are MIDI, SCSI, IrDA, and Bluetooth. These ports are not included in typical computers. For a computer to have these ports, you must customize the computer purchase order.

Buses

A bus allows the various devices both inside and attached to the system unit to communicate with each other.

Bays

A Bay is an opening inside the system unit in which you can install additional equipment. A bay is different from a slot, which is used for the installation of adapter cards.

Types of Expansion Buses

The PCI bus (Peripheral Component interconnect bus) is a high speed expansion bus that connects higher speed devices.Accelerated Graphics (AGP)- is a bus designed by Intel to improve the speed with which 3-D graphics and video transmit.The USB (universal serial bus)- is a bus that eliminates the need to install cards in expansion slots.

Power Supply

The power supply is the component of the system unit that converts the wall outlet AC power into DC power. Different motherboards and computers require different wattages on the power supply.