Transcript Why Study Computers?

Chapter 2
Hardware Designed to Meet
the Need
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Please discontinue use of cell
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The Digital Revolution
Integrated Circuits and Processing
Storage
Input, Output, and Expansion
Selecting and Purchasing a
Computer
The Digital Revolution
What’s all the
fuss about
digital?!
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The Bit (binary digit)
Recall from chapter 1….
 Bits are the 1’s and
0’s that allow us to
represent, store, and
manipulate data
 They are the smallest
unit of data in a digital
electronics device
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The Bit
 Bits aren’t really 1’s and 0’s, they
are devices that can be set to one
of two states.
 A bit can be a capacitor that is
electronic charged or not charged.
 A bit can be an area of metal particles
on the surface of a disk that are either
magnetically charged or not.
 A bit can be a microscopic spot on a
highly reflective disk surface that
either has a pit burned into it or not.
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The Bit
 How can a bit (an on-off switch) represent
useful data and information?
 Information can be assigned to the two
states of the bit:
 On =
 Off =
1 and 0 are typically used to describe the state of
a bit, but you could use anything; black/white,
true/false, male/female, etc.
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Bit & Bytes
 Bytes can also represent “values” using
the binary number system.
 The binary number system uses only
two values, 0 and 1, and is used by
computers and digital devices to
represent and process data.
Decimal
239
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Binary
11101111
Bit & Bytes
128 64 32 16
8
128 64 32 16 8
4
4
2
2
1
1
Click to run Binary Counter –
position counter here.
Binary is not only used for math but also to digitize pictures, and music. In
fact, most things that we perceive with our senses can be described and
stored digitally as values (binary numbers) and manipulated with numeric
calculations.
More on this in chapter 6.
Also see http://pic.fsu.edu/colormap.exe
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The Value of Going Digital
 Anything that can be expressed through
words, numbers, sounds, pictures, and even
scents can be digitized.
 Digital information is easy to manipulate.
 Digital information is easy to copy and
transfer.
 Digital information is long lasting.
 Digitization standardizes the format of all
different types of data and information
leading to…
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Digital Convergence
 Digital
convergence is
the trend to
merge multiple
digital services
into one device.
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Why Study Computer
Hardware Components?
Consider PC Choices…
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Key
Components
Processor
Memory
Storage
Removable Storage
Video
Networking
Security
OS
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2.2
Integrated Circuits and
Processing
Key Terms
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transistor
Integrated circuit
Central Processing Unit (CPU)
Motherboard
Arithmetic/logic unit
Control unit
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Random Access Memory (RAM)
The machine cycle
Megahertz (MHz)
Gigahertz (GHz)
Gigaflop
Moore’s Law
Transistor
 A transistor is an
electronics
component,
composed typically of
silicon, that opens or
closes a circuit to alter
the flow of electricity
to store and
manipulate bits.
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Integrated Circuit
 An Integrated Circuit
(chip) combines
transistors and
capacitors in a tiny
module to store and
process bits and bytes
in today’s digital
electronic devices.
http://www.intel.com/technology/silicon/index.htm
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The Central Processing Unit
 The Central
Processing Unit
(CPU) is an
integrated circuit
(or microprocessor)
that performs the
processing in
today’s personal
computers and
other digital
devices.
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Intels Core Duo Processors use
65 nm technology to cram
hundreds of millions of
transistors on a chip the size of
you thumb nail.
Silicon Wafer
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Pentium 4
Die photo of the Intel®
Pentium® 4 Processor
built on 90nm technology
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Chicago, IL
Satellite image of Chicago
Which is more complex?
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CPU Components
 Arithmetic Logic Unit (ALU): contains the circuitry
to carry out the instructions in the processors
instruction set.
 Control Unit: sequentially accesses program
instructions, decodes them, and coordinates the
flow of data throughout the system.
 Registers: hold the data and instructions currently
being processed (~300 bytes).
 System Clock: provides a steady clock signal used
to synchronize activities within the processor.
Measured in GHz (billions of cycles per second)
 Cache Memory: Fast access memory for
instructions and data soon to be needed (1-2MB).
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The Motherboard
 The motherboard
is the primary circuit
boards of a
computing device
that houses the
digital device’s
circuitry including
the microprocessor
and memory.
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Processing
 The microprocessor accesses instructions
stored in memory over the system bus.
Random Access
Memory (RAM) is
temporary, or volatile,
memory that stores
bytes of data and
program instructions
for the processor to
access.
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CPU
FSB
Graphics
Northbridge
FSB
RAM
disk drives
input
expansion
Southbridge
Chipset
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Processing – The Machine Cycle
Central Processing Unit
Control Unit
2.Decode
1.Fetch
ALU
3.Execute
Registers
4.Store
Memory
A simulation: Little Man Computer
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The Machine Cycle
The four stages of the
machine cycle are (1) fetch
the instruction from memory,
(2) decode and (3) execute
the instruction, then (4) store
the results.
Contributors to CPU Speed
 Clock Speed – measured in Gigahertz
(GHz), billions of cycles per second
 Wordlength – how many bits can be
processed at a time (32 or 64)
 Cache size – 512 KB – 2 MB
 Front Side Bus Speed (FSB) – 345-840 MHz
 Architecture
http://www.intel.com/products/processor_number
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Multi-core processors
 A multi-core microprocessor is one which
combines two or more independent
processors into a single package, often a
single integrated circuit.
 Dual core
 Tri core (from AMD)
 Quad core
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Which processor is best?
 Truest Measures of Performance
 MIPS – millions of instructions per
second
 Gigaflops – billions of floating point
operations per second.
 Note that different instructions take
differing amounts of clock cycles.
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Multiple processors
 Multiprocessing is processing that occurs
using more than one processing unit.
 Parallel processing speeds processing by
linking several CPUs to operate at the same
time, in parallel.
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PC Processor Options
 www.intel.com
 AMD, an alternative to Intel
http://www.amd.com/us-en/
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Moore’s Law
 the number of transistors per square inch
on integrated circuits will doubled every 2 years.
Are we approaching the processing capability of a human?
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