Chapter 5
Computing Components
(adapted by SLU faculty)
Chapter Goals
• Understand a computer ad
• List the computer architecture components and
their function
• Describe the fetch-decode-execute cycle
• Describe how computer memory is organized
and accessed
• Name and describe different storage devices
• Define three methods of parallelism
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Computer Components
What does all this jargon mean?
• Intel® Core™i7-920 Processor (8MB L2 Cache, 2.66GHz)
• 6GB Tri-Channel DDR3 SDRAM at 1066MHz - 6 DIMMs
• 750GB - 7200RPM, SATA 3.0Gb/s, 16MB Cache
• 16X CD/DVD burner (DVD+/-RW)
• Dell 22 inch S2209W Flat Panel
• ATI Radeon HD 4670 512MB
• Integrated 7.1 Channel Audio
• Dell A525 2.1 Stereo Speakers with Subwoofer
• Dell USB Multimedia Keyboard
• Dell Premium Laser Mouse
• Dell 19 in 1 Media Reader with Bluetooth
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Be patient!
If you don't
know now, you
should know
shortly
Sizes in Perspective
What is a hertz?
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Sizes in Perspective
Admiral Grace Murray Hopper
– A coil of wire nearly 1,000 feet long
• Distance traveled by an electron along the wire
in the space of a microsecond
– A short piece of wire
• In the space of a nanosecond
– A bag containing grains of pepper
• In the space of a picosecond
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Stored-Program Concept
Figure 5.1 The von Neumann architecture
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Memory
Memory
A collection of cells,
each with a unique
physical address;both
addresses and
contents are in
binary
Arithmetic/Logic Unit
• Performs basic arithmetic operations such
as addition and subtraction
• Performs logical operations such as
AND, OR, and NOT
• Modern ALUs have a small amount of
temporary storage called registers
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Peripherals
(Input/Output Units)
Input Unit
A device through which data and programs from
the outside world are entered into the computer;
Can you name three?
Output unit
A device through which results stored in the
computer memory are made available to the
outside world
Can you name two?
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Control Unit
• Control unit
The organizing force in the computer
• There are two registers in the control unit
– The instruction register (IR) contains the
instruction that is being executed
– The program counter (PC) contains the
address of the next instruction to be executed
• Together, the ALU and control unit are
called the Central Processing Unit, or CPU
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Flow of Information
• The parts are connected to one another by
a collection of wires called a bus
Figure 5.2 Data flow through a von Neumann architecture
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The Fetch-Decode-Execute Cycle
Fetch the next instruction
Decode the instruction
Get data if needed
Execute the instruction
Why is it called a cycle?
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The Fetch-Decode-Execute Cycle
Figure 5.3 The Fetch-Execute Cycle
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RAM and ROM
Random Access Memory (RAM)
Memory in which each location can be
accessed and changed
Read Only Memory (ROM)
Memory in which each location can be
accessed but not changed
RAM is volatile, ROM is not
What does volatile mean?
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Secondary Storage Devices
• Because most of main memory is volatile and
limited, it is essential that there be other types of
storage devices where programs and data can be
stored when they are no longer being processed
• Secondary storage devices can be installed
within the computer box at the factory or added
later as needed
Can you name some of these devices?
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Magnetic Tape
The first truly mass
auxiliary storage
device was the
magnetic tape
drive
Figure 5.4 A magnetic tape
Magnetic Disks
• A read/write head travels across a spinning
magnetic disk, retrieving or recording data
Compact Disks
CD
“Compact Disc”, which uses a laser to read information stored optically
on a plastic disc; holds up to 800 MB of data
CD-R
read-only memory
CD-RW
both readable and writeable
DVD
“Digital Versatile Disk”, used for storing video and audio
480p video (720x480 pixels per frame)
holds 4.7 GB of data (9.4 GB double-layer)
Blu-Ray Disc
1080p video (1920x1080 pixels per frame)
holds 25 GB of data (50 GB double-layer)
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Touch Screens
A computer monitor that can respond to the user
touching the screen with a stylus or finger
There are three types
–
–
–
–
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Resistive
Capacitive
Infrared
Surface acoustic wave
(SAW)
Synchronous processing
One approach to parallelism is to have multiple processors
apply the same program to multiple data sets
Figure 5.7 Processors in a synchronous computing environment
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Pipelining
Arranges processors in tandem, where each
processor contributes one part to an overall
computation
Figure 5.8 Processors in a pipeline
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Shared Memory Multi-processors
Communicate through shared memory
Figure 5.9 Shared memory configuration of processors
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