1 copyright © 2003 prentice hall, incslides created by bob koziel

1

Copyright © 2003 Prentice Hall, Inc Slides created by Bob Koziel

2 Copyright © 2003 Prentice Hall, Inc

Chapter 2

Inside the System Unit

COMPUTERS IN YOUR FUTURE 2004COMPUTERS IN YOUR FUTURE 2004by Bryan Pfaffenberger and Bill Daley

Chapter 2

Inside the System UnitWhat You Will Learn

NEXT

SLIDE

Description of the data computers transfer or store Components found inside the system unit Components found on the motherboard How the CPU processes data Characteristics of a microprocessor’s performance Types of memory Purpose and types of expansion buses Differences between analog and digital electrical

impulses


ON

0 1

OR = 1 bit

1

0

0 0 001 1

0 0 0 01 1

OR

= 1 Byte

= 1 Byte

OFF

0

0

NEXT SLIDE

Describing Hardware Performance

Hardware performance refers to the amount of data a computer can store and how fast it can process the data.

Bit (Binary digit)– On or off state of electric current; considered the basic unit of information; represented by 1s and 0s (binary numbers).

Byte– Eight bits grouped together to represent a character (an alphabetical letter, a number, or a punctuation symbol); 256 different combinations.


8 bits = 1 Byte

1024 Bytes = 1 Kilobyte (KB)

1,048,576 Bytes = 1 Megabyte (MB)

1,043,741,824 Bytes = 1 Gigabyte (GB)

1,099,511,627,776 Bytes = 1 Terabyte (TB)

NEXT SLIDE

Millions, Billions, and More

Kilobyte, megabyte, gigabyte, and terabyte are terms that describe large units of data.

Data storage is measured using these terms. Example: 20 GB hard drive


1000 bits = 1 kilobit (kb)

1,000,000 bits = 1 megabit (mb)

1,000,000,000 bits = 1 gigabit (gb)

NEXT SLIDE

Millions, Billions, and More

Kilobits, megabits, and gigabits are terms that describe units of data.

Used for measuring data transfer rate (bits per second). Example: 56 kbps

6 Copyright © 2003 Prentice Hall, IncNEXT SLIDE

The System Unit

The system unit is boxlike case that houses the computer’s main hardware components.

Space taken up on the desk is called a footprint.

Form factor refers to how the internal components are mounted in the unit.


DesktopNotebook

Personal Digital Assistant

NEXT SLIDE

Types of System Units

8 Copyright © 2003 Prentice Hall, Inc I NEXT SLIDE

Inside the System Unit

Motherboard (mainboard)– Large printed circuit board with thousands of electrical circuits

Power supply– Transforms alternating current (AC) from wall outlets to direct current (DC) needed by the computer

Cooling fan– Keeps the system unit cool

Internal Speaker– Used for beeps when error is encountered

Drive bays– Housing for the computer’s hard drive, floppy drive, and CD-ROM / DVD-ROM drives


Microprocessor

Printer Port

Video Port

PCI Slots

Memory Slots

AGP Slot

Chipset

Click on terms to view larger images and informationKeyboard /

Mouse Ports

The Motherboard

10 Copyright © 2003 Prentice Hall, Inc I NEXT SLIDE

Components of the CPU

Control unit– Coordinates and controls all parts of the computer system.

Arithmetic-Logic unit– Performs arithmetic or logical operations.

Registers– Store the most frequently used instructions and data.


CPUs at Work

I NEXT SLIDE

Control Unit– Manages four basic operations (fetch, decode, execute, and write-back). The machine cycle or processing cycle:

• Instruction Cycle Fetch- Gets next program instruction from the

computer’s memory. Decode- Figures out what the program is telling the

computer to do.• Execution Cycle

Execute- Performs the requested action. Write-back (Store)- Writes (stores) the results to a

register or to memory.

Arithmetic-Logic Unit (ALU)– Performs basic arithmetic or logic operations. Adds, subtracts, multiplies, and divides Compares data to determine which one is larger or smaller.


Control unit ALU

Memory

Click to animate. Click one time only

NEXT SLIDE

The Processing Cycle


Microprocessor Performance

Data bus width– The number of pathways within the CPU that transfer data (8, 16, 32, or 64)

Word size– The maximum number of bits of data that the CPU can process at a time (8 bits, 16 bits, 32 bits, or 64 bits)

Operations per cycle (clock speed)– The number of clock cycles per second measured in Megahertz (MHz) or Gigahertz (GHz).

Superscalar– Carrying out more than one instruction per clock cycle.

Pipelining– Feeding a new instruction into the CPU at every step of the processing cycle.


Parallel Processing

Parallel processing involves using more than one CPU to improve performance.

Complex instruction set computer (CISC)– A chip that includes special-purpose circuits that carry out instructions at high speeds.

Reduced instruction set computer (RISC)– A chip with a bare-bones instruction set that results in a faster processing speed than CISC chips.

NEXT SLIDE


Intel Advanced Micro Devices (AMD)

Cyrix Motorola (Apple)

Pentium IV

Pentium MMX

Pentium III

NEXT SLIDE

Popular CPUs (of days gone by)


Memory is a term for a device that enables the computer to retain (store) information.

RAM ROM

Flash

NEXT SLIDE

Memory


DIMM

SIMM

NOTEBOOK DIMM

RIMM

NEXT SLIDE

Memory Modules


Memory Categories

Volatile memory– Contents of memory are erased when power supply is turned off. It is temporary storage. RAM– Random access memory holds data in locations

called memory addresses. Cache memory– Memory that the processor uses to store

frequently used instructions and data. Virtual memory– The computer uses the hard disk as an

extension of RAM.

Nonvolatile memory– Contents of memory are not erased when power is turned off. ROM– Read-only memory provides the instructions to start

the computer. Flash memory– Memory that can be rewritten.


Random Access Memory / RAM

RAM is a type of volatile memory that stores information temporarily so that it’s available to the CPU.


WEB

KEYBOARD

CPU

RAM

MONITORCLICK TO BEGIN ANIMATION

Copyright © 2003 Prentice Hall, Inc

HOW RAM WORKS

NEXT SLIDE


Virtual memory involves:

Part of the hard disk is reserved as RAM.

When RAM modules become full, the CPU accesses the hard disk to store and retrieve data.

Slower than RAM.

FULL

NEXT SLIDE

Virtual Memory


BIOS and CMOS BIOS– Basic input/output system is stored in ROM.

Its instructions provide the boot sequence when starting the computer.

The boot sequence includes:• POST– Power-on self-test checks memory and configures

video and other hardware.• Locating the disk drive with the boot sector which contains the

operating system.

CMOS– Complementary metal-oxide semiconductor is a type of memory which stores essential startup options. It stores the amount of memory installed and tracks date

and time. It is volatile.

NEXT SLIDE


Cache Memory Primary cache (Level 1 or L1)– Located within the

CPU chip, it is the memory the microprocessor uses to store frequently used instructions and data.

Secondary cache (Level 2 or L2; Backside Cache)– Located near the CPU, it is the memory between the CPU and RAM.

It is faster than RAM.


Chipset

A chipset is a collection of chips that work together.

It provides circuitry to move data to and from the rest of the computer.


Expansion slots

Expansion card

NEXT SLIDE

Input/Output (I/O) Buses

I/O buses are pathways that enable the CPU to communicate with input/output devices.

Typically the buses contain slots, called expansion slots, in which expansion cards are inserted.


Drive bays

On/off switch

Reset button

Indicator lights

FRONT

BACK

NEXT SLIDE

Outside the System Unit

Power switch– Is located on the back. It turns power on/off to the computer.

Receptacles– Also called connectors or ports, are located on the back to plug in peripheral devices, keyboard, mouse, and monitor.

Front panel– Contains drive bays, various buttons, and lights.


Types of Ports

PS/2 port (mouse port)– Special serial port to connect mouse.PS/2 port (keyboard port)– Special serial port to connect keyboard.Universal Serial Bus (USB)– Allows up to 127 devices to be connected at a time.Serial port– Data flows in a series of pulses, one after another one bit at a time; slow data transfer rate.Parallel port– Data flows through eight wires allowing the transfer of eight bits of data simultaneously; faster than serial ports.VGA connector– A 15 pin connector used for monitorsGame port– A connector for high speed access for graphics-intensive interaction.Sound card connectors– Also called jacks, they accept stereo mini-plugs. Microphone, line-in, line-out, and speaker connectors are used.

Click on a port below to view information about it. Click again to remove the text.

NEXT SLIDE


SERIAL PARALLEL

NEXT SLIDE

The difference between serial and parallel ports


Analog Digital

OFFON

NEXT SLIDE

How a Computer Represents Data

Computers represent data through electronic signals or impulses.

Two types of signals:

Analog– Continuous waveform. Examples: talking and computerized gas pumps

Digital– On/off electrical states (bit). Examples: light switches and transistors


0 10 0 001 1

0 0 0 0 0 01 1

= 4

= A

NEXT SLIDE

Character Codes Numerical data, that computers use;

translated into characters readable by humans.

American Standard Code for Information Interchange (ASCII)– Eight bits; used by minicomputers and personal computers

Extended Binary Coded Decimal Interchange Code (EBCDIC)– Eight bits; used by mainframe computers

Unicode– Uses 16 bits; over 65,000 combinations

31 Copyright © 2003 Prentice Hall, Inc NEXT SLIDE

Chapter 2 Summary1. The basic unit of information is the bit.

2. Large units of data are kilobyte (KB), megabyte (MB), gigabyte (GB), and terabyte (TB).

3. The motherboard is a circuit board that provides receptacles for chips and input/output buses.

4. The central processing unit (CPU) contains the control unit (CU) and the arithmetic-logic unit (ALU). It manages the four basic operations (fetch, decode, execute, and write-back).

5. The CPU’s performance is measured by the data bus width, operations per second, speed, and cache memory.

6. Random access memory (RAM) is the computer’s main memory. It is volatile.

1. The basic unit of information is the bit.

2. Large units of data are kilobyte (KB), megabyte (MB), gigabyte (GB), and terabyte (TB).

3. The motherboard is a circuit board that provides receptacles for chips and input/output buses.

4. The central processing unit (CPU) contains the control unit (CU) and the arithmetic-logic unit (ALU). It manages the four basic operations (fetch, decode, execute, and write-back).

5. The CPU’s performance is measured by the data bus width, operations per second, speed, and cache memory.

6. Random access memory (RAM) is the computer’s main memory. It is volatile.

32 Copyright © 2003 Prentice Hall, Inc NEXT SLIDE

Chapter 2 Summary cont.

7. There are various types of RAM. They include dynamic RAM (DRAM), synchronous DRAM (SDRAM), Rambus DRAM (RDRAM), and double data rate (DDR)SDRAM.

8. Peripheral devices connect to the computer on the outside of the case.

9. Computers have ports such as serial ports, parallel ports, SCSI ports, USB ports, FireWire ports, and IrDA ports to connect input/output devices.

10.Analog computers measure and digital computers count.

7. There are various types of RAM. They include dynamic RAM (DRAM), synchronous DRAM (SDRAM), Rambus DRAM (RDRAM), and double data rate (DDR)SDRAM.

8. Peripheral devices connect to the computer on the outside of the case.

9. Computers have ports such as serial ports, parallel ports, SCSI ports, USB ports, FireWire ports, and IrDA ports to connect input/output devices.

10.Analog computers measure and digital computers count.


THE

END

1 copyright © 2003 prentice hall, incslides created by bob koziel

Documents