computer concepts 4th edition parsons/oja chapter 5 page 206 digital electronics section a computer...

Computer Concepts 4th EditionParsons/Oja

CHAPTER

5

Page 206

Digital ElectronicsSection A

Computer Architecture


Section D

Chapter

5Section A

07

Section A

Identify the components that are on the main circuit board - the motherboard -of a microcomputer

Section PREVIEW

You will be able to:

Digital Electronics


Chapter

5

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Section A

Computer architecture refers to the design and construction of a computer system.– based on power source– based on how computer physically represents,

processes, moves, and stores data Modern computers are powered by electricity and

use electric signals and circuits to represent, process, and move data.

Section A Digital Electronics


Inside the System Unit

What does the inside of a computer look like?

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5

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Section A

PowerSupply

CD-ROM drive

Floppydisk drive

Harddisk drive

Wires andribbon cables

Circuitboards


Integrated Circuits

Why isn’t the system unit filled with a lot of wires?

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Section A

Most electronic components inside a computer are integrated circuits - thin slices of silicon crystal packed with microscopic circuit elements– wires– transistors– capacitors– resistors


Integrated Circuits

Why isn’t the system unit filled with a lot of wires?

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Section A

Inside a computer, you are likely to find several kinds of chip packages, including DIP, DIMM, PGA, and SEC.

Example ofDIPs


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Chips are housed on a circuit board called a motherboard.– contains processor chip– computer memory chips– chips that handle basic input/output– contains expansion slots for peripheral

devices Some chips are soldered (permanent), some

are removable (can be upgraded)

The Motherboard

How do the chips fit together to make a computer?

Chapter

5

Section A


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The Motherboard

How do the chips fit together to make a computer?

Chapter

5

Section A

Supportchips

CircuitryMicroprocessorchip

Random accessmemorychips

ROMchips

Expansioncards


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Most of today’s computers are digital devices– work with distinct numbers or digits

An analog device operates on continuously varying data

Digital Data Representation

If a computer is just a bunch of electrical circuits, how can it manipulate data?

Chapter

5

Section A

The pulse ofelectricity downa circuit couldrepresent 1 bit


Data Representation Codes

Do all digital computers use the same code to represent data?

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Section A

Computers represent data using the binary number system and several other codes designed for computer data.

Binary number system (base 2)– has only two digits: 1 and 0– converted into “ons” and “offs”– number 2 cannot be used

Numeric data - numbers that represent quantities


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Chapter

5

Section A

Character data is composed of letters, symbols, and numerals that will not be used in arithmetic operations.– name, address, etc.

Digital computers represent character data using ASCII (American Standard Code for Information Interchange) and EBCDIC.

IBM-brand mainframe computers often use EBCDIC (Extended Binary-Coded Decimal Interchange Code).


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Chapter

5

Section A

An exampleof data codes


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Data travels from one location to another on an electronic circuit called a data bus.

Data bus - series of circuits that connect various electrical components on the motherboard– contains data lines and address lines

Data lines - carry the signals that represent data

Address lines - carry signals that specify where computer can find data to process

Data Transport

What happens to the data in a computer?

Chapter

5

Section A


CHAPTER

5

Page 215

MemorySection B



Section D

Chapter

5

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Section B

Explain how RAM, virtual memory, ROM, and CMOS differ

Section PREVIEW


MemorySection B


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5

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Section B

There are four major types of memory, each characterized by the data it contains and the technology it uses to hold the data.

MemorySection B


Random Access Memory

How does RAM work?

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Section B

RAM (random access memory) - an area of the computer that holds data before and after it is processed– as you type, characters are held in RAM

Capacitors are microscopic electronic parts that hold the electronic signals for the code that represents data.– charged capacitor = ON– discharged capacitor = OFF– each bank of capacitors holds eight bits



How does RAM work?

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Section B

Each RAM locationhas an addressand holds onebyte of databy using eightcapacitors to represent the eight bits in a byte.


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How does RAM work?

Chapter

5

A RAM address on each bank helps the computer locate the data in that bank.

RAM is a reusable computing source. RAM is volatile: requires power to hold data.


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Section B

RAM Functions

Why is RAM so important?

Chapter

5

Section B

RAM– holds data waiting to be processed– holds instructions that will process the data– holds processed data before it is stored

elsewhere– holds operating system instructions


6

Section B

RAM Capacity, Speed, and Configuration

How much RAM does my computer need?

Chapter

5

Section B

Storage is measured in RAM Today’s computers have between 64 and 256

megabytes of RAM Amount of RAM depends on software you use You can purchase additional RAM Today’s RAM has access speeds as fast as 8

nanoseconds, one billionth of a second RAM is configured as a series of DIPS soldered

onto a circuit board called a DIMM


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A computer can use disk storage to simulate RAM. This is called virtual memory.– not as fast as RAM

Section B

Virtual Memory

What if I run out of RAM?

Chapter

5

Section B


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Section B

Read-Only Memory

If a computer has RAM, why does it need ROM?

Chapter

5

ROM (read-only memory) is one or more chips containing instructions that help a computer prepare to process tasks.

Since RAM is empty when a computer is turned on, ROM BIOS is used.

ROM BIOS (basic input/output system) is a set of instructions that tells computer how to access the disk drives and peripheral devices.


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Section B

CMOS Memory

If the boot instructions are permanent, can I change any hardware on my system?

Chapter

5

A computer needs a semi-permanent way of keeping boot data, such as the number of hard disk sectors and cylinders.

CMOS memory - holds data but requires very little power to retain its contents.– can run by a battery on the motherboard– housed within the same chip carrier as ROM

BIOS Some computers have plug and play feature for

updating CMOS.


CHAPTER

5

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Central Processing UnitSection C



Section D

Chapter

5

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Section C

Explain how the CPU performs instructions contained in a computer program

List the factors that affect CPU performance

Section PREVIEW




Chapter

5

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Section C

The central processing unit is the circuitry in a computer that executes instructions to process data.



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In 1945, the size of a CPU was measured in feet; today, they are measured in mils (0.001 inch)

Central Processing Unit Architecture

What does the CPU look like?

Chapter

5

Section C

The ENIACbuilt in 1944was two feetwide and eightfeet high.


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Section C

In a microcomputer, the CPU is a single integrated circuit called a microprocessor.




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Section C

The CPU has two parts ALU (arithmetic logic unit)

– performs arithmetic operations– performs logical operations– uses registers to hold data being processed

The result of an operation is place in the accumulator.

From accumulator data, it can be sent to RAM or used for further processing.




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Chapter

5

Section C



The CPU’s control unit directs and coordinates processing.

The control unit’s instruction pointer tracks sequence of instructions.– places in instruction register


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Chapter

5

Section C



play animation f0518


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An instruction (a series of simple steps) tells the computer to perform arithmetic, logical or control operations.

Op code - part of the instruction which stands for operation code is a command word such as:– add– compare– jump

Operand - specify data or address of data for operation

Instructions

What specifies the steps that the CPU must perform to accomplish a task?

Chapter

5

Section C


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Section C

JMP M1

In this example JMP means jump and M1 is the RAM address of the instruction the computer is supposed to go to.

An instruction set is the list of instructions a CPU is able to execute.

Instructions

What specifies the steps that the CPU must perform to accomplish a task?

op code operand


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Instruction Cycle

How does a computer process instructions?

Chapter

5

Section C

The process in which a computer executes a single instruction is called the instruction cycle.


CPU Performance Factors

How does the architecture of a computer contribute to its performance?

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5

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Section C

CPU speed is influenced by several factors:– clock rate– word size– cache– instruction set size

A computer with a high-performance processor may have:– slow hard disk– small amount of RAM– no disk cache


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A computer’s system clock is not the same as a “real-time” clock.

System clock - emits pulses to establish the timing for all system operations– sets speed for data transport and

instruction execution The time it takes to complete an instruction

cycle is measured in megahertz.

Clock Rate

What does the date and time have to do with CPU performance?

Chapter

5

Section C


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Section C

Word Size

Which is faster, an 8-bit processor or a 64-bit processor?

Chapter

5

Section C

Word size - the number of bits that the CPU can manipulate at once.– based on size of registers in CPU– based on number of data lines in the bus


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Cache - special high-speed memory that gives CPU more rapid access to data

The cache ensures that data is immediately available whenever the CPU requests it.

Cache

Is there a process that speeds access to data from RAM?

Chapter

5

Section C


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Computers based on a CPU with a complex instruction set known as CISC (complex instruction set computer) machine.

A RISC (reduced instruction set computer) has limited set of instructions that it can perform quickly.

Instruction Set Complexity

What’s the difference between CISC and RISC?

Chapter

5

Section C


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Computers with a single processor execute instructions serially (one at a time).

Pipelining - technology in which processor can begin executing next instruction before it completes previous instruction.

Pipelining and Parallel Processing

Can a CPU increase its performance by executing more than one instruction at a time?

Chapter

5

Section C


Page 228

A computer with more than one processor can execute multiple instructions simultaneously, referred to as parallel processing.

Computers that use parallel processing are called parallel computers.

Pipelining and Parallel Processing

Can a CPU increase its performance by executing more than one instruction at a time?

Chapter

5

Section C


CHAPTER

5

Page 229

Input/OutputSection D



Section D

Chapter

5

Page 229

Section D

Describe how the data bus and the expansion bus work

List the components necessary to connect a peripheral device to a computer and describe each component’s role

Section PREVIEW




Chapter

5

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Section D

You will most likely want to add equipment to your computer to expand its capabilities

I/O (computer jargon for input/output) refers to collecting data and transporting results.

Expansion bus - the segment of the data bus that transports data between RAM and peripheral devices



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Chapter

5

Section D


1. Data originatesin RAM

2. Expansionbus transports dataalong circuits on the motherboard.

3. Expansion slotextends the expansionbus to an expansioncard 4. Expansion card

contains a port

5. Data cable plugs into the port, then leads to a peripheraldevice.


Expansion Slots and Cards

How do I use expansion slots?

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5

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Section D

Expansion slot - long, narrow socket on the motherboard into which you can plug an expansion card

Expansion card - small circuit board that provides computer with ability to control storage, input or output device

Most microcomputers have 4 - 8 expansion slots.


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Chapter

5

Section D

Today’s microcomputers come with – graphics card (for connecting monitor)– modem (for transmitting data over phone or

cable lines)– sound card (for connecting speakers)




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The microcomputer motherboard typically has:– ISA - older technology, modems and slow

devices– PCI - for graphics, sound, video, modem or

network cards– AGP - for graphics cards

Expansion cards are built for only one type of slot.

Chapter

5

Section D




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Expansion Ports and Cables

How do I connect a peripheral device to an expansion card?

Chapter

5

Section D

To connect a peripheral device to an expansion card, you plug a cable from the device into the expansion port.

Expansion port - any connector that passes data in and out of a computer or peripheral device.


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Chapter

5

Section D

Expansion Ports and Cables

How do I connect a peripheral device to an expansion card?


CHAPTER

5

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User Focus Troubleshooting Boot Process



Section D

Chapter

5

Page 234

Troubleshoot the boot process of your computer system

Section PREVIEW




Chapter

5

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User Focus

Boot process - sequence of events that occurs between the time you turn on a computer and the time it is ready for you to issue commands



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Chapter

5

User Focus

An Overview

If the computer memory is blank when I turn it on, how does it know how to start up?

The boot process follows these steps:

1. Power up

2. Start boot program

3. Power-on self-test

4. Load operating system

5. Check configuration and customization

6. Ready for commands and data


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Chapter

5

User Focus

Power Up

What if I turn the computer on but nothing happens?

If nothing happens, the system is not getting power.

When you turn on a computer, you should see the power lightand hear the fan.

Fan

Power light


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Chapter

5

User Focus

Start Boot Program

What happens if the ROM is malfunctioning?

If the ROM chips, RAM modules, or microprocessor are malfunctioning, the microprocessor will be unable to run the boot program.

The computer stops or “hangs”.– light is on – fan is on– no message on screen


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Chapter

5

User Focus

Power-On Self-Test

Can the computer check to determine if all its components are functioning correctly?

The Power-On Self-Test (POST) diagnoses problems in the computer.

POST – checks graphics card– tests RAM– checks keyboard– performs drive test


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Chapter

5

User Focus

Check Configuration and Customization

Does the computer get all of its configuration data from CMOS?

The computer checks CMOS; however, more configuration data is needed.

The computer searches root directory for configuration settings.– stored as Config.sys or Windows Registry

Windows Registry - contains settings that a computer needs to correctly use its hardware devices and software


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Chapter

5

User Focus

Ready for Commands and Data

How do I know when the computer has finished booting?

The boot process is complete when the computer is ready to accept your commands.

You can enter commands andlaunch programs.


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Chapter

5

User Focus

Ready for Commands and Data

How do I know when the computer has finished booting?

If Windows cannot complete the boot process, you’re likely to see an option to choose Safe Mode.

Safe Mode - limited version of Windows that allows you to use mouse, monitor, and keyboards– no peripherals.

computer concepts 4th edition parsons/oja chapter 5 page 206 digital electronics section a computer...

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