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Transcript of 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
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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
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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
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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.
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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)
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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
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1000 bits = 1 kilobit (kb)
1,000,000 bits = 1 megabit (mb)
1,000,000,000 bits = 1 gigabit (gb)
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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
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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.
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DesktopNotebook
Personal Digital Assistant
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Types of System Units
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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
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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
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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.
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CPUs at Work
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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.
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Control unit ALU
Memory
Click to animate. Click one time only
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The Processing Cycle
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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.
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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.
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Intel Advanced Micro Devices (AMD)
Cyrix Motorola (Apple)
Pentium IV
Pentium MMX
Pentium III
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Popular CPUs (of days gone by)
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Memory is a term for a device that enables the computer to retain (store) information.
RAM ROM
Flash
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Memory
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DIMM
SIMM
NOTEBOOK DIMM
RIMM
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Memory Modules
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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.
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Random Access Memory / RAM
RAM is a type of volatile memory that stores information temporarily so that it’s available to the CPU.
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WEB
KEYBOARD
CPU
RAM
MONITORCLICK TO BEGIN ANIMATION
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HOW RAM WORKS
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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
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Virtual Memory
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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.
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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.
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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.
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Expansion slots
Expansion card
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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.
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Drive bays
On/off switch
Reset button
Indicator lights
FRONT
BACK
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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.
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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.
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SERIAL PARALLEL
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The difference between serial and parallel ports
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Analog Digital
OFFON
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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
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0 10 0 001 1
0 0 0 0 0 01 1
= 4
= A
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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
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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.
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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.
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THE
END