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Using Information
Technology
Chapter 4
Hardware: The CPU & Storage
4.1
Microchips, Miniaturization, & Mobility
4.2
The System Unit
4.3
Secondary Storage
Hardware--The CPU & Storage
Hardware: The CPU & Storage
How to Buy a Multimedia Computer
System
2
4.1 Microchips, Miniaturization, & Mobility

Transistor - a tiny
electrically
operated switch,
or gate, that can
alternate between
“on” and “off”
many millions of
times per second.
1940s vacuum tube towering over
1950s transistor
Hardware--The CPU & Storage
From Vacuum Tubes to Transistors to Microchips
3
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Semiconductor – material whose electrical properties
are intermediate – a good conductor of electricity and a
nonconductor of electricity.
Silicon – element found in sand and clay that is a good
semiconductor.
Chip (microchip) – a tiny piece of silicon containing
millions of electronic circuits.
CPU (Processor) - contains millions of miniature
electronic circuits.
Microprocessor – “Processor on a chip” - Central
processing unit etched on silicon chip
Hardware--The CPU & Storage
Terms
4
4.2 The System Unit

The binary system has only
two digits - 0 and 1

Bit - binary digit

Byte - group of 8 bits used
to represent one character,
digit, or other value
Hardware--The CPU & Storage
The Binary System: Using On/Off Electrical States
to Represent Data & Instructions
5
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Kilobyte 210 B (approx 1 thousand bytes - 103)
Megabyte 220 B (approx 1 million bytes - 106)
Gigabyte 230 B (approx 1 billion - 109)
Terabyte 240 B (approx 1 trillion bytes – 1012)
Petabyte 250 B (approx 1 quadrillion bytes - 1015 )
Hardware--The CPU & Storage
The Binary System: Using On/Off
Electrical States to Represent Data &
Instructions
6
 ASCII - the binary
code most widely
used with
microcomputers.
 EBCDIC - used with
large computers.
 Unicode - uses two
bytes for each
character rather than
one byte (8 bits).
Hardware--The CPU & Storage
The Binary System: Using On/Off
Electrical States to Represent Data &
Instructions
7
Machine Language
Machine language – The programming
language that a computer can
understand. It consists of 0’s and 1’s.
Hardware--The CPU & Storage

8
The Computer Case: Bays, Buttons
& Boards
System unit houses the
motherboard,
power supply, and
storage devices.
Overhead view of system unit
Hardware--The CPU & Storage

9

Motherboard - the main circuit board in
the system unit.

Expansion Slot (located on the
motherboard) – a place to plug in
additional circuit boards in order to
increase a computer’s capabilities.
Hardware--The CPU & Storage
The Motherboard & the
Microprocessor Chip
10
Microprocessor
Key Components



Central Processing Unit
System clock
Registers
Hardware--The CPU & Storage

11
The Motherboard & the Microprocessor
Chip
Two principal architectures or designs of
microprocessors:
1. CISC (Complex Instruction Set Computing) Supports a large number of instructions at
relatively low processing speeds.
2. RISC (Reduced Instruction Set Computing) Used mostly in workstations, a great many
seldom-used instructions are eliminated.
Hardware--The CPU & Storage

12
The Motherboard & the Microprocessor
Chip
Two kinds of microprocessors used in
most personal computers today:
1. Intel-type chips made by Intel, AMD,
and others.
2. Motorola-type chips made by Motorola
for Apple Macintosh computers.
Hardware--The CPU & Storage
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13
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MHz – megahertz – million cycles per
second
GHz – gigahertz – billion cycles per second
MIPS – Millions of Instructions Per Second
FLOPS – Floating-point Operations Per
Second
Hardware--The CPU & Storage
Processing Speeds (Abbreviations)
14
Processing Speeds: From
Megahertz to Picoseconds
Microcomputers
Mainframes
X
X
X
MIPS
X
FLOPS
Fractions of
a second
Supercomputers
X
X
X
X
Hardware--The CPU & Storage
Megahertz &
Gigahertz
Workstations
15
Hardware--The CPU & Storage
How the Processor or CPU works:
Control Unit, ALU, & Registers
16
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
Controls how fast all operations within
a computer take place.
Delivers a steady stream of digital
pulses (ticks) to the CPU.

Each tick is one cycle.
Hardware--The CPU & Storage
System Clock
17
Register
High-speed storage area.
Hardware--The CPU & Storage
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18
When running a program.
The CPU follows the instructions of the
software in order to manipulate the
data into information.
Hardware--The CPU & Storage

19
The CPU consists of:
The control unit – for directing electronic
signals.


The control unit contains registers.
The ALU (arithmetic/logic unit) – for
arithmetic and logical operations and to
control the speed of those operations.

The ALU contains registers also.
Hardware--The CPU & Storage

20
Machine Cycle
One machine cycle consists of the
following:
1.
2.
3.
4.
Control Unit gets an instruction from memory
and places it into a register.
Control Unit determines what the instruction
means (decodes it) and determines the memory
location of the data required.
Control Unit moves data from memory into
registers in the ALU. The ALU executes the
arithmetic or logical operations.
Control Unit stores the results of these
operations in memory or in a register (if result is
needed for further operations).
Hardware--The CPU & Storage
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21
1.
2.
3.
4.
Fetch
Decode
Execute
Store
Hardware--The CPU & Storage
Machine Cycle
22
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lines through which electrical data is
transmitted.
copper tracing on the motherboard
Also exists in the CPU -data is
transmitted within the CPU and
between the CPU and other
components of the motherboard.
Hardware--The CPU & Storage
Bus (bus lines)
23
Bus Width
Refers to how many bits can be
transferred at one time.
Hardware--The CPU & Storage
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How Memory Works: RAM, ROM,
CMOS, & Flash
1.
2.
Types of memory chips:
RAM – to temporarily store program instructions
and data (Volatile)
ROM – to store fixed start-up instructions (Nonvolatile)

3.
CMOS – to store flexible start-up instructions.



4.
Can not be altered by the user.
powered by a battery and therefore does not lose data
when the computer is turned off.
Keeps the current time & date.
Can be altered by the user.
Flash – to store flexible programs


can be erased and reprogrammed more than once.
Used not only in personal computers but also cellphones,
digital cameras, pagers etc.
Hardware--The CPU & Storage
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25
Types of RAM
DRAM

2.
SDRAM

3.
static RAM
RDRAM

5.
synchronous dynamic RAM
SRAM

4.
dynamic RAM
rambus dynamic RAM
DDR-SDRAM

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double-data rate synchronous dynamic RAM
popular in notebook computers
 These types differ in:
1.
whether or not the CPU must refresh data in
order to maintain that data.
Hardware--The CPU & Storage
1.
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1.
2.
3.
Dynamic – must be refreshed by
the CPU
Static – retains its contents without
having to be refreshed by the CPU
Synchronous – means it is
synchronized by the system clock.
Hardware--The CPU & Storage
Terms dealing with the types
of RAM
27
Hardware--The CPU & Storage
Continued.
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