Computer Hardware
HARDWARE
The term hardware refers to the physical
components of your computer such as the system
unit, mouse, keyboard, monitor etc.
SOFTWARE
The software is the instructions that makes the
computer work.
Software is held either on your computers hard
disk, CD-ROM, DVD or on a diskette (floppy disk)
and is loaded (i.e. copied) from the disk into the
computers RAM (Random Access Memory), as
and when required.
TYPES OF COMPUTER
Mainframe computer
Mini-computer
Super-computer
Networked computer
Laptop computer
What is the difference between a PC and a Mac?
Mini and Mainframe Computers
 Very powerful, used by large
organisations such an banks to control
the entire business operation. Very
expensive!
Personal Computers
 Cheap and easy to use. Often used as
stand-alone computers or in a network.
May be connected to large mainframe
computers within big companies.
Brief History of Machine Hardware cont..
1970s
Computers were classified by capacity and price.
Mainframe was a large machine – in size and internal
memory capacity.
IBM 360 introduced in 1964 – a classic example of a
mainframe.
Its applications were generally limited to large computer
centers belonging to the federal government.
Brief History of Machine Hardware cont..
• Minicomputer was developed to meet the needs of
smaller institutions.
• DEC marketed the early minicomputers to many
sectors.
• Smaller than mainframes in memory capacity and
cheaper.
* Today computers that fall between mirocomputers and
mainframes are often called midrange computers
Brief History of Machine Hardware cont..
• Supercomputers was developed primarily for
government applications needing massive and fast
number-crunching abilities.
• Cray supercomputer is a typical example with six to
thousands of processors
• Often used to create or perform intricate calculations
and in animated motion pictures.
Brief History of Machine Hardware cont..
• Microcomputer was developed to offer inexpensive
computation capability to individual users.
• Grew to accommodate software with larger capacity
and greater speed.
Brief History of Machine Hardware cont..
• Servers are powerful computers that provide
specialized services to other computers on a
client/server network.
• e.g. file server, print, internet, etc…
Brief History of Machine Hardware cont..
• Workstations are powerful microcomputers
developed for use by commercial, educational, and
government enterprises.
• Are networked together and is used in engineering,
CAD and other applications requiring strong PCs,
Case that contains
electronic
components of the
computer used to
process data
•
•
Sometimes called
the chassis
The System Unit
Processors

Components of System Unit

power supply
Memory
drive bays

Adapter cards
- Sound card
- Video card
processor
ports
memory



video card
Ports
Drive bays
Power supply
sound card
The System Unit
Motherboard
•
Main circuit board in
system unit
•
Contains adapter cards,
processor chips, and
memory chips
•
Also called system board
The System Unit
Chips
•
Small piece of semiconducting material on
which integrated circuits
are etched.
•
•
Chips are packaged so
they can be attached to a
circuit board
The System Unit
Processors
•
Interprets and carries out
basic instructions that operate
a computer
•
Also called the CPU (Central
Processing Unit)
•
The CPU is the brain within your
computer.
The System Unit
The CPU's speed is measured in MHz.
Processor
Control
Unit
Arithmetic
Logic Unit (ALU)
Memory
Electronic components that store
instructions, data, and results
•
Consists of one or more chips
on motherboard or circuit board
•
Types of Memory
RAM vs. ROM
RAM
Electronic components that
Store instructions, data, and
Results
•
Consists of one or more
Chips on motherboard or
circuit board
Memory chips that can be
read from and written
to by processor
•
Also called
main memory
or primary
storage
Most RAM is
volatile, it is lost
when computer’s
power is
turned off
The more RAM a
computer has, the
faster it responds
The main 'working'
memory used by the
computer.
What are two basic types of RAM chips?
Static
RAM
(SRAM)
Most
common
type
Must be
re-energized
constantly
Dynamic
RAM
(DRAM)
Do not have to
be re-energized
as often as
DRAM
Faster and
more reliable
than DRAM
chips
Newer Type: Magnetoresistive RAM (MRAM)
p. 199
Next
Where does memory reside?
•
•
Resides on small
circuit board called
memory module
Memory slots on
motherboard hold
memory modules
p. 199 Fig. 4-18
memory chip
dual inline memory module
memory slot
Next
How much RAM does an application require?
•
Depends on the types of software you plan
to use
•
For optimal performance, you need more
than minimum specifications
p. 199
Next
ROM
• as the name suggests is a special type of memory
chip that holds software that can be read but
not written to.
• A good example is the ROM-BIOS chip, which
contains read-only software.
•
Often network cards and video cards also contain
ROM chips.
What is read-only memory (ROM)?
Memory chips that store
permanent data
and instructions
Nonvolatile memory, it is not
lost when computer’s
power is turned off
Three types:
EEPROM
(electrically
Firmware—
erasable programmable
Manufactured with
read-only memory)—
permanently written
Type of PROM
data, instructions,
containing microcode
or information
PROM
programmer
(programmable
can erase
read-only
memory)—
Blank ROM
chip onto which
a programmer
can write permanently
p. 201
What is access time?

Amount of time it takes processor
to read data from memory

Measured in nanoseconds (ns),
one billionth of a second

It takes 1/10 of a second to blink your eye; a computer can
perform up to 10 million operations in same amount of time
Term
p. 203 Figs. 4-22-4-23
Millisecond
Microsecond
Nanosecond
Picosecond
Speed
One-thousandth of a second
One-millionth of a second
One-billionth of a second
One-trillionth of a second
Next
RAM - Random Access Memory
The main 'working' memory used by the computer.
As a rough rule, a Microsoft Windows based computer
will operate faster if you install more RAM. Data and
programs stored in RAM are volatile (i.e. the
information is lost when you switch off the computer).
ROM – Read Only Memory
Read Only Memory (ROM) as the name suggests is a
special type of memory chip that holds software that
can be read but not written to.
A good example is the ROM-BIOS chip, which contains
read-only software.
Often network cards and video cards also contain
ROM chips.
HOW COMPUTER MEMORY IS MEASURED?
Bit
 All computers work on a binary numbering system, i.e. they process data in
one's or zero's. This 1 or 0 level of storage is called a bit.
Byte
 A byte consists of eight bits.
Kilobyte
 A kilobyte (KB) consists of 1024 bytes.
Megabyte
 A megabyte (MB) consists of 1024 kilobytes.
Gigabyte
 A gigabyte (GB) consists of 1024 megabytes.
THE FACTORS THAT IMPACT ON A
COMPUTER'S PERFORMANCE
• CPU speed
• RAM size
• Hard disk speed and capacity
What is flash memory?
•
•
Nonvolatile memory that can be erased electronically and
rewritten
Used with PDAs, digital cameras, smart phones, music
players, digital voice recorders, printers, Internet receivers,
and pagers
Step 3.
Step 1.
Purchase and download MP3 music
tracks from a Web site. With one end of
a special cable connected to the system
unit, connect the other end into the MP3
player.
Plug the headphones into the MP3 player,
To headphonespush a button on the MP3 player, and listen
to the music through the headphones.
Flash memory chip
From computer
Flash memory card
Step 2.
Instruct the computer to copy the MP3
music track to the flash memory chip in the
MP3 player.
p. 202 Fig. 4-21
MP3 Player
What is CMOS?
Complementary metaloxide semiconductor
memory
Uses battery
power to retain
information when
other power is turned
off
p. 203
Used in some
RAM chips, flash
memory chips, and other
types of memory chips
Stores date,
time, and
computer’s
startup
information
EXPANSION SLOTS AND ADAPTER CARDS
What is an adapter card?
•
Enhances system unit or provides
connections to external devices
called peripherals
•
Also called an expansion card
A peripheral device is any device that you can
attach to your computer.
Thus you could attach a scanner or modem to
the back of your system unit.
EXPANSION SLOTS AND ADAPTER CARDS
What is an expansion slot?

An opening, or socket,
on the motherboard
that can hold an
adapter card

With Plug and Play,
the computer automatically
configures cards and other devices as you install them
p. 204 Fig. 4-25
EXPANSION SLOTS AND ADAPTER CARDS
What are PC cards, and flash memory cards?

A PC card adds memory, storage,
sound, fax/modem, communications,
and other capabilities to notebook
computers

A flash memory card allows users to
transfer data from mobile devices to
desktop computer.
USB Flash drive

p. 205 Fig. 4-26–4-27
Next
PORTS AND CONNECTORS
What are ports and connectors?


Port connects external devices to system unit
Connector joins cable to peripheral
 Available in one of two genders: male and female
PORTS AND CONNECTORS
What are different types of connectors?
p. 207 Fig. 4-29
Next
What are different types of connectors?
(continued..)
What is a serial port?


Transmits one bit of
data at a time
Connects slow-speed
devices, such as mouse,
keyboard, modem
p. 207 Fig. 4-30
Next
What is a parallel port?

Connects devices that
can transfer more than
one bit at a time, such
as a printer
p. 208 Fig. 4-31
Next
PORTS AND CONNECTORS
What are USB ports?
USB (universal serial bus) port can connect
up to 127 different peripherals together
with a single connector type
PCs typically have
six to eight USB ports
on front or back of
the system unit
p. 208
Single USB port can
be used to attach
multiple peripherals
in a daisy chain
First USB
device connects
to USB port
on computer
Third USB
device connects
to second USB
device, and so on
Second USB
device connects
to first USB
device
Next
What are FireWire ports?
Connects multiple types of devices
that require faster data transmission
speeds
 Allows you to connect up to
63 devices together

p. 209
Next
PORTS AND CONNECTORS
What are special-purpose ports?

Allow users to attach specialized peripherals or transmit data
to wireless devices
 MIDI (Musical Instrument Digital
Interface) port
 SCSI (small computer system
interface) port
 IrDA (Infrared Data Association)
port
 Bluetooth port
BUSES
What is a bus?
Channel that allows devices inside computer to
communicate with each other




System bus connects processor
and RAM
Bus width determines number
of bits transmitted at one time
Word size is the number of
bits processor can interpret
and execute at a given time
Click to view Web Link,
click Chapter 4, Click Web Link
from left navigation,
then click Buses below
Chapter 4
p. 211 Fig. 4-35
Next
What is an expansion bus?

Allows processor to communicate with peripherals
FireWire
Bus
p. 212
USB
Bus
AGP
Bus
PCI
Bus
Next
BAYS
What is a bay?

Open area inside
system unit used to
install additional
equipment

Drive bays typically
hold disk drives
Next
DEVICES FOR INPUTTING DATA
The Mouse
 Used to ‘drive’ Microsoft Windows
The Keyboard
 The keyboard is still the commonest
way of entering information into a
computer
Tracker Balls
 an alternative to the traditional
mouse and often used by graphic
designers
DEVICES FOR INPUTTING DATA
Scanners
 A scanner allows you to scan printed material and
convert it into a file format that may be used within
the PC
Touch Pads
 A device that lays on the desktop and responds to
pressure
Light Pens
 Used to allow users to point to areas on a screen
Joysticks
 Many games require a joystick for the proper playing
of the game
COMMON OUTPUT DEVICES
VDU
 The computer screen is used for
outputting information in an
understandable format for humans.
Also called:
Monitor or Display Unit
CRT (Cathode Ray Tube)
- Employs a similar display that
to a television set. Where the
image is projected from the
cathode. The number of pixels
determines the quality of the
image projected.
LCD (Liquid Crystal Display)
- uses two sheets of polarizing material
with a liquid crystal solution between
them. An electric current passed
through the liquid causes the crystals
to align so that light cannot pass
through them.
CRT vs. LCD
LCD
CRT
RESOLUTION
CRT is flexible and a newer
model will provide you with
viewing resolutions of up
to 1600 by 1200 and
higher,
LCD the resolution
is fixed within each
monitor (called a
native resolution).
LCD
CRT
RESOLUTION
the sharpness of the
picture can be
blemished by soft
edges or a flawed
focus
when an LCD is running at
its native resolution the
picture quality is perfectly
sharp
LCD
CRT
REFRESH RATE
Some users of a CRT may
notice a bit of an annoying
flicker, which is an inherent
trait based on a CRTs
physical components.
LCDs are flicker-free
and as such the
refresh rate isn't an
important issue with
LCDs.
LCD
CRT
SCREEN SIZE
When you purchase a 17inch CRT monitor, you
usually get 16.1 inches
If you purchase a 17"
LCD monitor, you
actually get a full 17"
viewable area, or very
close to a 17".
LCD
CRT
PHYSICAL SIZE
CRT monitors are big,
bulky and heavy.
LCD wins in terms of its
physical size and the space
it needs. CRT monitors are
big, bulky and heavy.
DID YOU KNOW...
In March 2009 Hitachi Displays plead guilty to
LCD price fixing joining LG Display, Chunghwa Picture
Tubes (CPT) and Sharp. Hitachi will pay US$31 million
in fines for its role in fixing LCD prices sold to Dell for
LCD monitor and notebook PC applications according
to the US Department of Justice.
Printers
There are many different types of printers.
In large organizations laser printers are most
commonly used due to the fact that they can print
very fast and give a very high quality output.
COMMON OUTPUT DEVICES
Plotters
 A plotter is an output device similar to a
printer, but normally allows you to print
larger images.
Speakers
 Enhances the value of educational and
presentation products.
Speech synthesisers
 Gives you the ability to not only to
display text on a monitor but also to
read the text to you
STORAGE DEVICES
Internal Hard Disks
Speed:
 Very fast!
 The speed of a hard disk is often quoted as "average access time" speed,
measured in milliseconds. The smaller this number the faster the disk.
Capacity:
 Enormous! Often in excess of 500 Gigabytes. A Gigabyte is equivalent to
1024 Megabytes.
Cost:
 Hard disks costs are falling rapidly and normally represent the cheapest
way of storing data.
• Hard disks are the main, large data storage
area within your computer.
• Hard disks are used to store your operating
system, your application programs (i.e. your
word processor, games etc) and your data.
STORAGE DEVICES
External Hard Disks
Speed:
 Normally slower than internal disks, but more expensive
versions offer the same performance as internal hard
disks.
Capacity:
 Same as internal disks.
Cost:
 More expensive than internal disks.
STORAGE DEVICES
CD-ROM Disks
Speed:
 Much slower than hard disks. The original CD-ROM speciation is now
given a value of 1x speed, and later, faster CD-ROMs are quoted as a
multiple of this value.
Capacity:
 Around 650 Mbytes.
Cost:
 Below £100 each (UK sterling).
STORAGE DEVICES
DVD Drives
Speed:
 Much faster than CD-ROM drives but not as fast as hard disks.
Capacity:
 Up to 17 Gbytes.
Cost:
 Slightly higher than CD-ROM drives.
POWER SUPPLY
What is a power supply?
Converts
AC Power
into
DC Power
Fan keeps
system unit
components
cool
External peripherals
might use an AC
adapter, which is an
external power supply
p. 213
Next
MOBILE COMPUTERS AND DEVICES
What is a mobile computer?

Notebook, weighing between 2.5 and 8 pounds, or mobile
device such as a PDA
p. 213 Fig. 4-37
Next
MOBILE COMPUTERS AND DEVICES
What ports are on a notebook computer?
p. 214 Fig. 4-38
Next
MOBILE COMPUTERS AND DEVICES
What ports and slots are on a tablet PC?
p. 214 Fig. 4-39
Next
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