Chapter 4 The Components of The System Unit Matt Vanacore, Ryan Bratton, Thomas Bender

Chapter 4Chapter 4

The Components of The System The Components of The System UnitUnit

Matt Vanacore, Ryan Bratton, Thomas Matt Vanacore, Ryan Bratton, Thomas BenderBender

Copyright 2004Copyright 2004

The System UnitThe System Unit

• Is a case that contains electronic Is a case that contains electronic components of the computer used to components of the computer used to process dataprocess data– The motherboard is the main circuit The motherboard is the main circuit

board of the system unitboard of the system unit

• A chip is a small piece of semi A chip is a small piece of semi conducting material on which conducting material on which integrated circuits are etchedintegrated circuits are etched


ProcessorProcessor

• Interprets and carries out the basic instructions that Interprets and carries out the basic instructions that operate a computeroperate a computer

• Contains a control unit and a arithmetic logic unit Contains a control unit and a arithmetic logic unit (ALU)(ALU)– Performs arithmetic operations, which is basic arithmetic Performs arithmetic operations, which is basic arithmetic

(addition, subtraction etc) and Comparison, which involves (addition, subtraction etc) and Comparison, which involves comparing data with other data.comparing data with other data.

– Logical operations uses “and,” “or,” and “not.” It must Logical operations uses “and,” “or,” and “not.” It must verify conditions.verify conditions.

• The control unit directs and coordinates most of the The control unit directs and coordinates most of the operations in the computer.operations in the computer.

• Both of these units work together to perform Both of these units work together to perform processing operationsprocessing operations


Processor Cont.Processor Cont.

• Registers are small high speed storage Registers are small high speed storage locations that temporarily hold data.locations that temporarily hold data.

• The computer relies on the System The computer relies on the System Clock to control timing of all computer Clock to control timing of all computer operations.operations.– Each tick is a clock cycle, clock speed is Each tick is a clock cycle, clock speed is

measured by the number of ticks per measured by the number of ticks per second.second.

– A hertz is one cycle per secondA hertz is one cycle per second


Processor Cont.Processor Cont.

• The four major manufacturers of The four major manufacturers of Processors are Intel, IBM, AMD, and Processors are Intel, IBM, AMD, and Motorola.Motorola.

• Most high performance computers use the Most high performance computers use the Pentium Processor, which is manufactured Pentium Processor, which is manufactured by Intel.by Intel.

• AMD manufactures processors similar and AMD manufactures processors similar and compatible to Intel, but not always as compatible to Intel, but not always as powerfulpowerful


Data RepresentationData Representation

• Two types of data representationTwo types of data representation– AnalogAnalog is a continuous signal that varies in strength and is a continuous signal that varies in strength and

qualityquality• HumansHumans

– DigitalDigital recognize only two discrete states, on and off recognize only two discrete states, on and off• ComputersComputers

• Binary system (bit) is a number system that has two Binary system (bit) is a number system that has two unique digits, 0 and 1. This is the smallest unit of unique digits, 0 and 1. This is the smallest unit of datadata

• 8 bites together form a byte, and this has enough 8 bites together form a byte, and this has enough combinations to represent 256 individual characterscombinations to represent 256 individual characters


MemoryMemory

• Consists of electronic components that store Consists of electronic components that store instructions waiting to be executed by the processor, instructions waiting to be executed by the processor, data needed by those instructions, and the results of data needed by those instructions, and the results of processed data.processed data.

• Three basic categories:Three basic categories:– Operating system and other system software that control or Operating system and other system software that control or

maintain the computer and its devicesmaintain the computer and its devices– Application programs that carry out specific tasksApplication programs that carry out specific tasks

• WordWord– Data being processed by the application programs and Data being processed by the application programs and

resulting information.resulting information.

• RAMRAM consists of memory chips that can be read from consists of memory chips that can be read from and written to by the processor and other devicesand written to by the processor and other devices


Memory ContinuedMemory Continued

• RAM RAM has three different typeshas three different types– Dynamic RAMDynamic RAM are chips that must be re- are chips that must be re-

energized constantly or they lose their energized constantly or they lose their contentscontents

– Static Static RAMRAM chips are faster and more chips are faster and more reliable then any variation of reliable then any variation of DRAMDRAM chips chips

– Magnetoresistive Ram stores data using Magnetoresistive Ram stores data using magnetic charges instead of electrical magnetic charges instead of electrical chargescharges


Memory Cont.Memory Cont.

• Memory Cache Memory Cache helps speed the helps speed the process of the computer because it process of the computer because it stores frequently used instructions and stores frequently used instructions and data.data.– L1 cache is built directly into the processor.L1 cache is built directly into the processor.– L2 cache is slightly slower than L1, but has L2 cache is slightly slower than L1, but has

much larger capacity.much larger capacity.– L3 cache is a cache separate from the L3 cache is a cache separate from the

processor chip on the motherboard.processor chip on the motherboard.



• ROMROM refers to every chip storing permanent data refers to every chip storing permanent data and instructions.and instructions.

• Firewall Firewall contains permanently written data, contains permanently written data, instructions, or information.instructions, or information.

• A A PROMPROM chip is a blank ROM chip onto which a chip is a blank ROM chip onto which a programmer can write permanently.programmer can write permanently.

• EEPromEEProm chip allows a programmer to erase the chip allows a programmer to erase the microcode with an electrical signal.microcode with an electrical signal.

• FLASH MEMORY FLASH MEMORY is a type of none volatile is a type of none volatile memory that can be erased electronically and re-memory that can be erased electronically and re-written.written.



• CMOS CMOS complimentary metal-oxide complimentary metal-oxide semiconductor technology because it semiconductor technology because it provides high speeds and consumes little provides high speeds and consumes little power.power.

• Memory Access TimeMemory Access Time is the amount of is the amount of time it takes the processor to read data, time it takes the processor to read data, instructions, and information from instructions, and information from memory.memory.– NanosecondNanosecond is one billionth of a second is one billionth of a second


Expansion Slots and Adapter CardsExpansion Slots and Adapter Cards

• Expansion slide is a socket on the motherboard Expansion slide is a socket on the motherboard that can hold an adapter card.that can hold an adapter card.

• An adapter card is a circuit board that enhances An adapter card is a circuit board that enhances functions of a component.functions of a component.

• A peripheral is a device that connects to the A peripheral is a device that connects to the system unit and is controlled by the processor in system unit and is controlled by the processor in the computer. the computer.

• A sound card enhances the sound generating A sound card enhances the sound generating capabilities of a personal computer by allowing capabilities of a personal computer by allowing sound to be input through microphone and output sound to be input through microphone and output through external speakers. through external speakers.

• A video card converts computer output into a A video card converts computer output into a signal that travels through a cable to the monitor signal that travels through a cable to the monitor which displays an image on the screen.which displays an image on the screen.


ADAPTER CARDS ADAPTER CARDS CONTINUEDCONTINUED• A modem card is a communication device that A modem card is a communication device that

enables computers to communicate via telephone enables computers to communicate via telephone lines, television or other media. lines, television or other media.

• A network card is a communications device that A network card is a communications device that allows a computer to access a network.allows a computer to access a network.

• Plug and play is the computer automatically Plug and play is the computer automatically configuring adaptor cards.configuring adaptor cards.

• The pc card slot hold the pc card and the pc card The pc card slot hold the pc card and the pc card is a small device that adds memory, storage, is a small device that adds memory, storage, sound, and other communications.sound, and other communications.

• Flash memory card is used to transfer data from Flash memory card is used to transfer data from mobile devices to desk top computers.mobile devices to desk top computers.


Ports and ConnectorsPorts and Connectors

• A port is a point at which a peripheral attaches to a A port is a point at which a peripheral attaches to a system unit to send or receive datasystem unit to send or receive data

• A connector joins a cable to a peripheralA connector joins a cable to a peripheral– Male connectors have one or more exposed pinsMale connectors have one or more exposed pins– Female connectors have matching holes to accept the pins Female connectors have matching holes to accept the pins

on a male connectoron a male connector– A gender changer is a device that connects both male and A gender changer is a device that connects both male and

male or female and femalemale or female and female

• Serial port is a type of interface that connects a Serial port is a type of interface that connects a device to a system unit by transmitting data one bit device to a system unit by transmitting data one bit at a timeat a time

• A parallel port is a interface that connects devices A parallel port is a interface that connects devices by transferring more then one bit at a time.by transferring more then one bit at a time.


Ports and Connectors ContinuedPorts and Connectors Continued• USB ports can connect up to 127 different USB ports can connect up to 127 different

peripherals together with a single connector typeperipherals together with a single connector type• A USB hub is a device that plugs into a USB port on A USB hub is a device that plugs into a USB port on

the system unit and contains multiple USB portsthe system unit and contains multiple USB ports• Firewire port is similar to a USB, but it transfers data Firewire port is similar to a USB, but it transfers data

fasterfaster• MIDI port is the electronic music industries that MIDI port is the electronic music industries that

defines how devices such as sound cards represent defines how devices such as sound cards represent sound electronicallysound electronically

• SCSI port is a high speed parallel port that allows you SCSI port is a high speed parallel port that allows you to attach SCSI peripherals such as disc drives and to attach SCSI peripherals such as disc drives and printersprinters

• IrDA transmits signals to a computer via infrared IrDA transmits signals to a computer via infrared light waveslight waves

• Bluetooth ports uses radio waves to transmit dataBluetooth ports uses radio waves to transmit data


BusesBuses

• A bus allows the various devices both inside and A bus allows the various devices both inside and attached to the system unit to communicateattached to the system unit to communicate

• Word size is the number of bits the processor can Word size is the number of bits the processor can interpret and execute at a given timeinterpret and execute at a given time

• Data transmitted to memory travels from Data transmitted to memory travels from expansion bus via the expansion bus and the expansion bus via the expansion bus and the system bus.system bus.


BaysBays

• A bay is an opening inside the system A bay is an opening inside the system unitunit

• In which you can install additional In which you can install additional equipment.equipment.

• Rectangular openings called Rectangular openings called Drive Drive baysbays typically hold disk drives. typically hold disk drives.

• An external drive bay allows the user An external drive bay allows the user to access the drive from outside the to access the drive from outside the system unit.system unit.


Power SupplyPower Supply

• Power SupplyPower Supply is the component of the system is the component of the system unit that converts the wall outlet AC power into unit that converts the wall outlet AC power into DC power.DC power.

• An An AC AdapterAC Adapter is an external power supply, is an external power supply, which modems, speakers, and tape drives get which modems, speakers, and tape drives get their power from.their power from.


Mobile Computers and DevicesMobile Computers and Devices

• Two types of computing mobile devices are the Two types of computing mobile devices are the tablet PC (Laptop) and a PDA (Palm Pilot).tablet PC (Laptop) and a PDA (Palm Pilot).

• The laptop is similar to the desktop in almost The laptop is similar to the desktop in almost every way except that many of the devices are every way except that many of the devices are part of the system unit.part of the system unit.

• PDA’s have external keyboards and they often PDA’s have external keyboards and they often have Bluetooth ports so they can communicate have Bluetooth ports so they can communicate wirelessly.wirelessly.


Putting It All TogetherPutting It All Together

• People buying computers should how the People buying computers should how the components of the system work because they components of the system work because they influence many aspects of the computer.influence many aspects of the computer.

Documents

Chapter 4 The Components of The System Unit Matt Vanacore, Ryan Bratton, Thomas Bender