5. Learning Objective:
At this end of this Lesson the students can be
able to:
Define concisely what is computer.
Identify the basic functions of computer.
Discuss the evolution of computer.
Discuss the different generation of computer.
Classify and differentiate computer types.
6. Definition
Is an electronic device that:
5+2
5+2
5+2=7 5+2=7
7. Computer: Basic Function
A device that:
1. accepts input
input – whatever is put into the computer system.
ex. words, symbols, numbers, pictures, audio signal,
instructions from a computer program.
needs an input device
2. process data
data – refers to symbols that represent facts, objects, and
ideas.
process – a way in which a computer manipulates data
this process is controlled by a computer program.
processing takes place in a CPU (brain of computer)
8. Computer
A device that:
3. stores data
Types of Data Storage
1. Memory – (volatile)
ex. memory card, CMOS
2. Storage Device –(non-volatile)
ex. hard disk, floppy disk, usb flash disk, CD‟s etc.,
3. Why is it important for a computer to have a data
storage?
4. produces output
output – is the results produced by a computer.
ex. reports, documents, music, pictures, videos, etc.,
needs output devices
10. First Generation - 1940-1956: Vacuum Tubes
first computers used vacuum tubes for circuitry,
and were often enormous, taking up entire rooms
Magnetic drums as primary storage device
Uses machine languages for instr.
Input punched cards and paper tape
output printouts.
11. Examples of First Generation Computers
UNIVAC – the first commercial computer delivered to a
business client.
First seen….
ENIAC – the first computer used for scientific studies.
EDVAC – the first computer to hold both stored
program as well as data
13. Second Generation - 1956-1963: Transistors
Transistors replaced vacuum tubes
smaller, faster, cheaper, more energy-efficient and
more reliable.
Computers could handle an enormous amount of
data.
used in business, universities, and government
from companies.
14. Third Generation - 1964-1971: Integrated Circuits
Drastically increased the speed and efficiency of
computers.
Uses keyboards and monitors and interfaced with an
operating system.
Computers been able to run different application
program.
15. Fourth Generation - 1971-Present: Microprocessors
Microprocessor or processor is an integrated circuit
designed to process instructions.
CPU is the most important element of a computer
system
16. Assignment
1. Search the internet for the name of the first
UNIVAC, ENIAC and EDVAC created.
2. Search for the first computer program developed
for commercial use.
3. Search for different brands of processor and
compare the price of the processors with the
same specification. (example 2.4 GHz)
4. Search for significant contributions of the “Age of
Connectivity” – 1991 to present. Ex: WI-FI
18. Capabilities of Computer
Capabilities of the computer is defined by its
hardware and the software.
Capability of computer is endless and limitless
we cannot put boundary to its ability.
Qualities that defines computer capability:
1. Speed
2. Repetitiveness
3. Accuracy
4. Logic operation
5. Store and recall operation
6. Self checking
7. Self operation
7/27/2012 18
19. Scalability of Computer
Scalability is the ability of the system to improve
its performance with the additional hardware,
proportional to the additional load.
Dimension of Scalability:
Load scalability:
The ability of a machine to adjust its operation to
accommodate changing load.
Geographic scalability:
The ability to maintain performance when there
geographic growth.
Functional scalability:
The ability to enhance the system by adding new
functionality at minimal effort.
7/27/2012 19
20. General Applications of Computer
Scientific Research
Ex. Cloning, weather forecasting, etc..
Business / Commerce
Ex. Banking, online shopping, etc..
Entertainment
Ex. Movie effects, gaming, etc..
Education / Information Gateway
Ex. World wide web, e-learning, etc..
Connectivity/Communication
Ex. Email, web conferencing, blue tooth etc..
Aviation
Air Traffic Control, Satellite, etc..
Military Operations
Ex. Nuclear weapon, GPS (Global Positioning System), etc..
Programming
VBasic, Java, Perl, C++, Delphi, etc..
Artificial Intelligence
Robotics, Speech Recognition, etc..
7/27/2012 20
22. Classification of Computer
How do we classify computer?
1. Technology
2. Function
3. Physical Size
4. Performance
5. Cost
Computer Categories
1. Mainframe
2. Minicomputer
3. Microcomputer
4. Supercomputer
5. Server
23. Mainframe
Large, fast and expensive
Centralized storage, processing, distribution, and
management of large amount of data.
Reliable and secured.
used by businesses and government.
Mainframe usually comes in 3 units
overall operations
handles communication with all users.
finding data requested.
24. IBM System/360 (S/360)
speed from 0.034 MIPS
to 1.700 MIPS
designed to cover the
full range of
applications, from small
to large, both
commercial and
scientific.
The design is
considered by many to
be one of the most
successful computers in
history.
25. Minicomputer
minicomputer is a system capable of supporting from 4 to
about 200 users simultaneously
smaller, less expensive, and less powerful machines
Perform -> all terminals; business applications
Still existing?
26. The PDP-8 (1960’s)
the first successful
commercial minicomputer
built with discrete
transistors
Built 60‟s – distribute ‟65
Digital Equipment
Corporation (DEC)
27. Microcomputers
general-purpose computer useful for individuals,
and which is intended to be operated directly by an
end user
Also called personal computers, PC
ex. desktop, notebook, laptops, PDA
28. ALTAIR 8800
microcomputer design
from 1975,
based on the Intel
8080 CPU
sold thousands in the
first month.
recognized as the
spark that led to the
personal computer
revolution: computer
bus designed.
29. Apple II
1977 - one of the first highly
successful mass produced
microcomputer
among the first home
computers on the market,
and became one of the
most recognizable and
successful.
Sold between 5 and 6
million until 1993
30. Supercomputers
Fastest and most expensive (1M – 100M)
“Compute-intensive” tasks
Molecular modelling
Code breaking
Weather prediction
physical simulations
Speed -> Complex processing
Movement of thousands of particles in a tornado
Creating realistic animation
31. Illiac IV
one of the most
infamous
supercomputers ever
built.
256 processors –
parallel processing
32. The Cray 1
In 1975 the 80 MHz
Cray-1 was
announced.
designed by a team
including Seymour
Cray for Cray
Research.
design to use
integrated circuits
(ICs)
33. IBM Roadrunner
world's fastest computer
US$133-million
U.S (DoE) National Nuclear
Security Administration.
development since 2002,
and went online in 2006.
Feb 2009 – starts
development of “Sequia” –
20 petaflops
34. Server
A special type of computer that is configure to “serve” the
computers on a network.
store and distribute data and/or allow clients to exchange
files or access a centralized resources.
can be personal computer, a mainframe or a supercomputer.
38. Learning Objective:
At the end of this lesson, the student should be
able to:
Identify the different components of the computer
system.
Discuss the role and importance of each
component in the computer system.
Differentiate input devices from output devices.
Enumerate common input and output devices.
Define software and discuss its importance in the
system.
Enumerate the different types of software and their
functions.
43. Learning Objective
At the end of this lesson, the students should be able to:
Identify the components of the System Unit
Enumerate the components of the motherboard
Explain the function of the processor: the Control Unit, Arithmetic and Logic unit.
List and briefly explain the various types of memory.
Explain the function of buses and list different types of buses.
Explain the various types of ports and connectors.
Discuss the functions of expansion slots and adapter cards.
Differentiate internal and external bays.
Explain the function of power supply.
Define ‘bit’ and describe how a series of bits are used to represent data.
ext: Definition of System Unit
44. The System Unit
the main body of a computer.
Consist of:
motherboard
cooling fans,
internal disk drives
memory modules
expansion cards
power supply
ext: System Unit w/ labeled parts
46. Rear View of the system unit
ext: System Unit for portable
47. System Unit for Laptops and PDA
keyboard and
pointing device
are on top of the
system
display is part
of the unit
ext: Motherboard
48. The Motherboard
Also known as the system board.
main circuit board of the system unit.
Components attached to
the motherboard
processor
memory
buses
system clock
expansion slots and
adapter cards
ports
ext: Function of motherboard
49. Function of the Motherboard
provides means of communication between processor and
memory.
controls the flow of information through all the components.
bus is a subsystem that transfers data between computer
components inside a computer or between computers.
PCI Express bus card slots
(from top to bottom: x4, x16, x1
and x16), compared to a
traditional 32-bit PCI bus card
slot (bottom).
ext: Function in figure
50. bus provides
means of
transportation
bus stops are the
memory, the
processor and other
peripheral devices
bus carries data and
instruction from one
stop to another and
drop them off as
these stops
ext: Old Motherboard
51. Old Motherboard
Specifications
An old IBM 8088
Processor Intel 8088 motherboard
Speed 4.77 MHz
RAM 16K-640K
ROM Unknown
Cassette Tape,
optionally 5.25"
Storage
floppy drives, hard
disks
Expansion 5 expansion slots
Industry Standard
Bus
Architecture (ISA)
Initially CGA
(320x200x16
color, 640x200x2
Video
color) or
monochrome
(80x25 text only))
I/O Parallel, Serial
ext: Modern Mboard
52. Modern motherboards include, at a
minimum:
sockets (or slots) in which one or more microprocessors are installed
memory slots into which the system's main memory is installed
a chipset which forms an interface between the CPU's front-side bus,
main memory, and peripheral buses
non-volatile memory chips containing the system's firmware or BIOS
a clock generator which produces the system clock signal to
synchronize the various components
slots for expansion cards
power connectors flickers, which distribute electric power to the CPU,
chipset, main memory, and expansion cards.[
ext: Figure
55. The Processor
central processing unit (CPU)
brain of the computer
most important and most expensive
various sizes and speed
Two basic Components
1. Control Unit
2. Arithmetic and Logic Unit (ALU)
Functions of the processor
1. execute instructions
instructions from program
2. process data
ext: Device communication
56. How device communicates with
processor to complete a task
Processor
instruction
data
information
data information
instruction
data
input devices
information
output devices
ext: Control unit
Storage device
57. The Control Unit
components of the processor that manages all of the computer
resources.
control and directs the flow of data through the processor and to and from
other devices.
interprets the instructions for a program and executes necessary actions
to carry out the instruction.
ext: ALU
58. The Arithmetic And Logic Unit
performs arithmetic related operations,
comparison operations and logical operations.
Functions of Arithmetic Logic Unit (ALU)
Arithmetic
addition, subtraction, multiplication, division
Comparison
equal to, greater than, less than, greater or equal to, lesser
or equal to
Logical
AND, OR, NOT
ext: Machine cycle
59. The Machine Cycle
The repetition of series of steps for every
instruction the processor executes.
Machine Cycle
Instruction Cycle Execution Cycle
Fetching Decoding Executing Storing
Retrieves Translates Carries out Writes (stores)
(fetches) a (decodes) (execute) the results to
command/data instructions into commands listed memory.
from the memory signals the in the instructions
computer can
understand
ext: performance
60. Performance Factors of Processor
A. Registers
small, high-speed temporary storage located in the
ALU.
The amount of data which the computer can work with
at any given time is referred to as the word size.
word size is measured in bit
a 64-bit processor can process data twice as much as 32-
bit.
Functions of Registers
store the locations where instructions were fetched from.
store an instruction while the instruction is being decoded by
the control unit.
store data while the ALU computes the data.
store the results of calculations
ext: System clock
61. Performance Factors of
Processor
B. System Clock
timer that times the processing operations of the
computer.
sets the pace for executing instructions.
Clock cycle
Measured in hertz, cycles per second.
2.4 GHz means ~ 2.4 billion cycles per second.
processor can be able to execute instruction in
every cycle.
the speed of processor to carry out an instructions
depends on the speed of the system clock.
ext: Cache Memory
62. Performance Factors of
Processor
C. Cache Memory (“cash”)
sometimes called “RAM cache” or “cache
memory” – measured in KB or MB
Special high-speed memory that allows a
microprocessor to access data rapidly than from
memory located elsewhere on the motherboard.
Level1 cache(L1) – built into the processor chip.
Level2 cache(L2) – located on a separate chip and
takes little more time to get data to the processor.
used in motherboard, but was later built into the CPU
Usually tied with the processor brand and model –
non-upgradeable.
ext: Method of processing
63. Performance Factors of Processor
D. Method of processing
Processors are basically designed to process one
instruction at a time, this refers to as Serial Processing.
process must complete all of the steps of machine cycle before it
begins to process a new instruction.
Pipelining
a technology that allows a processor to begin a new instruction
before it completes the previous one.
Parallel Processing
new technology for new generation processors
allows simultaneous multi-processing.
pizza analogy
ext: Fast processor
66. Memory
Memory is an electronic components in your
computer that stores:
instructions waiting to be executed
data needed by the instructions and
the results of processed data.
How does computer finds requested data?
67. A1 B1 C1 D1
A2 B2 C2 D2
01101100 10001011
A3 B3 C3
01100111 10001100
D3 #9 Wilson St
Memory are virtual
location inside your
the content of each
computer
memory address is
each location has
called bytes
unique
identification called
address
ext: Memory Arcihtecture
69. Memory And Storage Size
Term Abbreviation Approximate Exact Amount Approximat
Size e Pages of
Text
Kilobyte KB or K 1 thousand 1,024 bytes ½
bytes
Megabyt MB 1 million bytes 1,048,576 bytes 500
e
Gigabyte GB 1 billion bytes 1,073,741,824 500,000
bytes
Terabyte TB 1 trillion bytes 1,099,511,627,776 500,000,000
bytes
stated in terms of the number of
bytes available for storage in the chip
or device
ext: Types
70. Types of Memory
Volatile Non-volatile
Temporary memory Permanent memory
Contents are lost when the Contents can be preserve
computer is turned off. even if the computer is off.
Common Type Common Types
RAM ROM
Random Access Memory Read-only memory
Flash memory
CMOS
ext: RAM
71. RAM
Main memory or primary storage
RAM is considered "random access"
because you can access any
memory cell directly
holds operating system files,
program files and data files needed
for processing.
can handle multiple programs
simultaneously.
Ram is volatile.
The process of copying items from RAM
to a storage device is known as saving.
What are the different types of ram
and which one is on your pc?
72. Types of Ram Chips
DRAM – Dynamic RAM SRAM – Static RAM
Needs to refresh thousands Doesn‟t need to refresh
of times to keep contents
Slower
Faster
Less Expensive than SRAM
Used for large amount of More expensive
temporary storage.
Used to create the CPU‟s
cache memory.
ext: DRAM
73. How Dynamic RAM Works
DRAM mainly consists of millions capacitors
and transistors
Transistor acts as a switch that control the
flow of electrons to the capacitors.
To store 1, the bucket is filled, to store 0 the
bucket is emptied.
0 and 1 represent bit, the smaller unit of
information in a computer.
The problem with the capacitor's bucket is
that it has a leak.
In a matter of a few milliseconds a full bucket
becomes empty.
Therefore, for dynamic memory to work,
either the CPU or the memory controller has
to come along and recharge all of the
capacitors holding a 1 before they discharge.
74. How Static RAM works
Static RAM uses flip-flop technology that holds each bit of
memory permanently while there is electric current.
Using flip-flop for a memory cell doesn‟t require refreshing but
requires a lot of wiring
This makes static RAM significantly faster than dynamic RAM but
takes up a lot more space on a chip than a dynamic memory cell.
Therefore, you get less memory per chip, and that makes static
RAM a lot more expensive.
used to create the CPU's speed-sensitive cache, while dynamic
RAM forms the larger system RAM space
ext: Types of RAM
75. Common Types of RAM
SRAM: DDR SDRAM:
Does not need refreshing, but Double data rate synchronous
requires several wiring connected to dynamic RAM is just like SDRAM
the transistors, used primarily for except that is has higher bandwidth,
cache. meaning greater speed.
DRAM: RDRAM: Rambus dynamic
type of memory that requires constant random access memory
refreshing. use of a special high-speed data bus
SDRAM: called the Rambus channel that
makes memory chips work in parallel
Synchronous dynamic random access to achieve a data rate of 600 MHz, or
memory 1,600 MBps.
faster than DRAM because they are Speed versus heat
synchronous with the system clock.
the most common form in desktops
today.
ext: Memory module
76. Memory Modules
SIMM, which stands for
single in-line memory
module.
30-pin connector, 3.5 x .75
inches in size – max 32 MB
In most computers, you had to
install SIMMs in pairs of equal
capacity and speed.
This is because the width of
the bus is more than a single
SIMM.
Later 4.25 x 1 – max 256 MB
ext: DIMM and RIMM
77. Memory Modules
DIMM, which stands for dual in-line
memory module.
168-pin or 184-pin connector, 5.4 x 1
inch in size
8 MB to 1 GB
RIMM, which stands for Rambus in-
line memory module
comparable in size and pin
configuration to DIMM but uses a
special memory bus to greatly increase
speed
800 MHz, or 1,600 MBps data rate
Can we use it for portable pc?
ext: SODIMM
78. Memory Modules
SODIMM, which stands for
small outline dual in-line
memory module
144 or 200 pins, 2 x 1 inch
16 MB to 1 GB per module.
used in notebooks and
laptops.
some notebook uses smaller
DIMMs, known as
MicroDIMM.
ext: Most common memory type
79. Other Memory Modules
Top L-R, DDR2 with heat-spreader, DDR2 without heat-spreader, Laptop
DDR2, DDR, Laptop DDR
ext: Access Time
80. Access Time
The amount of time it takes for the processor to read data,
instructions, and information from memory.
usually expressed in ns (nanoseconds).
Newer memory have speed expressed in MHz.
RAM TYPE RAM Speed
EDO 16 MHz (60 ns)
SDRAM 66 MHz (15ns) – 133 MHz (7.5ns)
RDRAM 600 MHz (1.7 ns) – 800 MHz (1.3 ns)
ext: How much do we need?
81. How much RAM do you need?
The amount of RAM for your system varies
depending on several factors.
1. The Operating System you‟re putting in to your
computer.
Windows 95/98, min of 32 MB, 64 MB is recommended.
Windows NT/2000 min 64 MB, 128 MB is recommended.
Windows XP, min 128MB, 256MB is recommended.
Windows Vista, min 256, 512 is recommended
2. How you‟re going to use your pc.
High-end user vs. basic user.
Does adding more RAM makes your computer
faster?
ext: Other Primary Storage
82. ROM
Read-only memory
also known as firmware, is an
integrated circuit programmed
with specific data when it is
manufactured.
ROM chips are used not only in
computers, but in most other
electronic items as well.
ext: Characteristics of ROM
83. Characteristics of ROM
Data stored in these chips is nonvolatile -- it is not lost when
power is removed.
Data stored in these chips is either unchangeable or requires a
special operation to change, unlike RAM.
Ideal memory for storing the BIOS
Basic Input Output System
ext: Types of ROM
84. Types of ROM
ROM
ROM uses a diode to its control circuit.
ROM chip works necessitates the programming of
perfect and complete data when the chip is created.
ROM are disposable.
They use very little power, are extremely reliable and,
in the case of most small electronic devices, contain
all the necessary programming to control the device.
ext: PROM
85. Types of ROM
PROM
programmable read-only memory
Blank chips that can be coded by anyone with a special
tool called a programmer.
Mainly consists of wires and fuses that needs to be burn
to embed program.
This process is known as burning the PROM.
PROMs can only be programmed once.
Blank PROMs are inexpensive and are great for
prototyping the data for a ROM before committing to the
costly ROM fabrication process.
ext: EPROM
86. Types of ROM
EPROM
Erasable programmable read-only
memory
Can be rewritable many times but needs
to be erased.
Erasing an EPROM requires a special
tool that emits a certain frequency of
ultraviolet (UV) light
Erasing requires removing into the
device and exposure under UV light for
several minutes.
ext: EEPROM
87. Types of ROM
EEPROM
Electrically erasable programmable read-only memory.
The chip does not have to removed to be rewritten.
The entire chip does not have to be completely erased to
change a specific portion of it.
Changing the contents does not require additional dedicated
equipment.
Instead of using UV light, you can return the electrons in the
cells of an EEPROM to normal with the localized application of
an electric field to each cell.
The process of rewriting is versatile but slow.
ext: FLASH
88. Types of ROM
Flash memory
type of EEPROM that uses in-circuit wiring to
erase by applying an electrical field to the entire
chip or to predetermined sections of the chip called
blocks.
Flash memory works much faster than traditional
EEPROMs because it writes data in chunks,
usually 512 bytes in size, instead of 1 byte at a
time.
ext: FLASH
89. FLASH
A portable storage devices that use a type of electronic memory called
flash memory.
also known as a solid state storage device, meaning there are no moving
parts instead purely electronic.
Here are a few examples of flash memory:
Your computer's BIOS chip
CompactFlash (most often found in digital cameras)
SmartMedia (most often found in digital cameras)
Memory Stick (most often found in digital cameras)
PCMCIA Type I and Type II memory cards (used as solid-state disks in
laptops)
Memory cards for video game consoles
ext: Flash vs HDisk
90. Advantages of using flash memory
over hard disk
There are a few reasons to
use flash memory instead of
a hard disk:
It has no moving parts, so it's
noiseless.
It allows faster access.
It's smaller in size and lighter.
Why can‟t we just use flash
memory for everything?
ext: CMOS
91. CMOS
Complementary Metal Oxide Semiconductor."
Technology used in some ROM chips, flash memory
chips and other types of memory.
run efficiently and fast but using up very little power.
You may also find CMOS memory in your computer,
which holds the date and time and other basic system
settings.
The low power consumption of CMOS allows the
memory to be powered by a simple Lithium battery for
many years.
93. Computer Bus
a subsystem that transfers data between
computer components inside a computer or
between computers.
allows the travel of bits from one destination to
another
bit is the smallest unit of data that computer can
process and store.
bit is represented by 0 and 1
0 and 1 are typically referred to as the machine
language.
8 bits = 1 byte
ext: Buses Diagram
94. Computer buses
•FSB or frontside bus
The backside bus is a is a physical
eparate connection connection that
etween the processor actually connects the
nd the Level 2 cache. processor to most of
This bus operates at the other
faster, usually at the components.
ame speed as the • usually operates at
rocessor, so all that 400-MHz, with newer
aching works as systems running at
•PCI bus
ficiently as possible. 800-MHz.
• These slower buses
connect to the system
bus through a bridge,
which is a part of the
computer's chipset
and acts as a traffic
cop, integrating the
data from the other
buses to the system
ext: Types bus.
95. Types of Buses
Internal Buses External Buses
also known as the system bus also known as expansion
or the local bus.
reside on the motherboard and bus.
connects the processor to connect external devices
other devices on the main
circuit board. into the main circuit
Data bus – used to send and board.
receive data between devices
Address bus – connects used by keyboard, mouse,
processor and ram, responsible monitor and printer
for addressing of requests.
ext: Factors
96. Factors That Affects the Speed of
data transfer
Bus Width
The number of bits that the computer can transmit
at one time.
32-bit bus can transmits 32 bits (4 bytes)
64-bit bus can transmits 64 bits (8 bytes)
Bus Speed
The speed that the bus could transfer data from
one device to another.
Measured in MegaHertz (MHz)
current bus speed is 400 MHz – 800 Mhz newer
ext: Standard Bus
97. Standards for Different Buses
1. ISA – Industry Standard Architectural Bus
2. VESA/VL Bus – Video Electronics Standard Association
Local Bus
3. PCI – Peripheral Component Interconnect Bus
4. AGP – Accelerated Graphic Port Bus
5. PCI Express– Peripheral Component Interconnect
Express Bus
6. USB – Universal Serial Bus
7. IEEE 1394 – Firewire
8. PC Card
9. Express Card
98. ISA
computer bus standard for IBM compatible
computers.
still used to connect slower devices, such as
modems and input devices to the processor.
Later on replaced by 32-bit EISA
Five 16-bit and one 8-bit ISA slots on a motherboard
99. VESA
Video Electronic Standard Association Local Bus
A VLB slot itself was an extension of an existing
ISA slot. Indeed, either a VLB or an ISA card could
be plugged into a VLB slot.
Bus width 32 bits
Compatible with 8 bit ISA, 16 bit ISA, VLB
100. PCI
Peripheral Component Interconnect
The PCI Local Bus developed by Intel is common in modern PCs,
where it has displaced ISA and VESA Local Bus as the standard
expansion bus, and it also appears in many other computer types
Offer past transfer speeds and a 32-bit or 64-bit data bus.
Typically house a graphics card, sound card, video card, video capture
card, modem, or network interface card.
101. AGP
Accelerated Graphics Port
a high-speed point-to-point channel for attaching a video card,
primarily to assist in the acceleration of 3D computer graphics.
The primary advantage of AGP over PCI is that it provides a
dedicated pathway between the slot and the processor rather
than sharing the PCI bus.
Number of devices: 1 device/slot Capacity up to 2133 MB/s
102. Specs for each generation per lane
PCI Express
a computer expansion card standard designed to replace the older
PCI and AGP standards.
Introduced by Intel in 2004, PCIe is the latest standard for expansion
cards that is available on mainstream personal computers.
Specs for each generation per lane
Clock Transfer
Data rate
speed rate
1.x 1.25 GHz 2.5 GT/s 250 MB/s A PCI Express x16 slot
2.0 2.5 GHz 5 GT/s 500 MB/s
3.0 4 GHz 8 GT/s 1 GB/s A PCI Express x1 slot
103. USB
Universal Serial Bus (USB)
USB was designed to allow many peripherals to be connected using a single standardized
interface socket and to improve plug and play capabilities by allowing hot swapping
hot swapping allows devices to be connected and disconnected without rebooting the computer
or turning off the device.
USB can connect computer peripherals such as mice, keyboards, PDAs, gamepads and
joysticks, scanners, digital cameras, printers, personal media players, flash drives, and
external hard drives. For many of those devices, USB has become the standard connection
method.
Supports up to 127 devices connected in a daisy chain
104. IEEE 1394 - FIREWIRE
The IEEE 1394 interface is a serial bus interface standard for high-
speed communications and real-time data transfer, frequently used by
personal computers, as well as in digital audio, digital video,
automotive, and aeronautics applications.
It remains the primary transfer mechanism for almost all high end
professional audio and video equipment.
Used by Mac but now available to IBM-compatible pc.
105. PC Card
PC Card (originally PCMCIA Card)
PCMCIA - Personal Computer Memory Card International
Association
form factor of a peripheral interface designed for laptop
computers.
PC Card was originally designed for computer storage
expansion, but later on become the form for attaching network
cards, modems, and hard disks.
Allows attach/detach without affecting the computer.
106. Express Card
ExpressCard is a hardware
standard expansion slot,
commonly found in laptop
computers, replacing older and
bigger PC Card slots.
Uses of E-Card
audio/video adapters,
storage modules
storage adapters
wireless adapters
TV tuners
various memory card readers.
Some popular ExpressCard®
applications include TV Tuners,
eSATA, FireWire, wireless WAN and
wireless networking.
108. Expansion Port
Expansion Port
Any connector that passes data in and out of a
computer or peripheral device.
could be housed on an expansion card.
could be built into the system unit.
How to figure out which connector for which port?
ext: Port Diagram
110. Universal Serial Bus (USB)
A serial bus standard to connect
devices to a host computer.
sends data over single data line.
1.0 – speed from 1.5Mbit/s to 120Mbit/s
2.0 – speed 480 Mbit/s
SB is a standard port designed to
improve plug and play capabilities by
allowing hot swapping.
hot swapping allows devices to be
connected and disconnected without
rebooting the computer or turning off the
device.
ext: Firewire
111. IEEE 1394 interface (FireWire)
A serial bus interface
standard for high-speed
communications and
real-time data transfer.
Since 2003 many
computers intended for
home or professional
audio/video use have
built-in FireWire.
ext: Ethernet
112. Ethernet Port
Ethernet is a family of
frame-based computer
networking technologies
for local area networks
(LANs).
It defines a number of
wiring and signaling
standards for the
Physical Layer of the
OSI networking model.
ext: Serial
113. Serial Port
A serial communication
physical interface through
which information transfers
in or out one bit at a time
(contrast parallel port).
Sends data over a single
data line one bit at a time at
speeds of 56 kbps.
Use to connect earlier
mouse or modem.
ext: Parallel
114. Parallel Port
A parallel port is a type of
interface for connecting various
peripherals. It is also known as
a printer port.
Sends data simultaneously over
8 data lines at speeds o 12,000
Mbit/s.
Printer, external CD-ROM drive,
Zip drive, external hard disk.
ext: PS/2
115. PS/2 Connector
The PS/2 connector is used for
connecting some keyboards and
mice to a PC compatible computer
system.
Its name comes from the IBM
Personal System/2 series of
personal computers,
Replaced the older "serial mouse"
and keyboard connector (but not
interchangeable)
Serial data at 10 to 16 kHz
ext: VGA
116. VGA Port
Video Graphics Array (VGA)
refers specifically to the display
hardware first introduced with
the IBM PS/2 line of computers
in 1987
also known as RGB connector,
D-sub 15, mini sub D15 and
mini D15
Used to connect an analog
monitor to the system unit.
ext: DVI
117. DVI Port
The Digital Visual Interface (DVI)
is a video interface standard
designed to provide very high
visual quality on digital display
devices such as flat panel LCD
computer displays and digital
projectors.
It is partially compatible with the
High-Definition Multimedia Interface
(HDMI) standard in digital mode
(DVI-D), and VGA in analog mode
(DVI-A).
ext: SCSI
118. SCSI - (pronounced scuzzy),
Small Computer System Interface
A set of standards for physically
connecting and transferring data between
computers and peripheral devices.
sends data simultaneously over 8 or 16
lines at speeds between 40Mbit/s and
640Mbit/s.
Supports up to 16 devices.
SCSI is most commonly used for hard
disks and tape drives, but it can connect a
wide range of other devices, including
scanners and CD drives.
120. Computer Drive Bays
Refers to a location in a system unit where a hard or
floppy disk drive, CD-ROM drive or tape drive can be
installed.
A drive bay is a standard-sized area for adding hardware
to a computer.
Thus, the number of drive bays in a computer determines
how many mass storage devices can be internally installed.
Commonly used to store disk drives, although they can
also be used for front-end USB ports, I/O bays, card
readers, fans, tool storage, and other uses.
ext: Type: Internal
121. Internal Bay
Also referred to as
hidden bays
There is no physical
outside access.
Cannot be used for
removable media,
such as floppy drives,
and USB.
ext: Type External
122. External Bay
Also referred to as
exposed bay
There is a need for
physical outside access.
Floppy, drives and CD-
ROMs slide into external
bays and can be seen
(and accessed) from the
front of your system case.
ext: Pow Supp
123. Power supply unit (computer)
A power supply unit (PSU) is
the component that supplies
power to the other components
in a computer.
Designed to convert (AC)
electric power to usable low-
voltage DC power for the
internal components of the
computer.
Some have power selector
while some have auto power
detection.
ext: Connector
124. Typical Connectors for the PS
PC Main power connector is the connector that goes to the motherboard to provide it with
power.
The connector has 20 or 24 pins.
4-pin Peripheral power connectors (usually called Molex for its manufacturer) that goes to
the various disk drives of the computer.
4-pin Berg power connectors (usually called Mini-connector or "mini-Molex"): This is one of
the smallest connectors that supplies the floppy drive with power.
Auxiliary power connectors: There are several types of auxiliary connectors designed to
provide additional power if it is needed.
ext: Digital Rep
126. Learning Objective
After this lesson, the students should be able to:
Define and differentiate computer program and
computer software.
Enumerate different type of software.
Differentiate System Software and Application
Software
Define and enumerate the different types of
System Software
Define and enumerate the different types of
Application Software
127. DEFINITION
COMPUTER PROGRAM
Is a set of detailed, step-by-step instructions that tells a
computer how to solve a problem or carry out a task.
COMPUTER SOFTWARE
The instructions and associated data, stored in
electronic format, that direct the computer to
accomplish the task.
Differentiate Software, Program and Application.
128. CLASSIFICATION of SOFTWARE
Software are classified based on how they could
be used.
1. Copyrighted Software
2. Licensed Software
3. Shareware
4. Freeware
129. Copyrighted Software
software that is exclusive to the owner or the developer.
copyright - form of legal protection that grants the copyright
exclusive rights to copy the software, to distribute or sell it,
and modify it.
I purchased a software, can I copy it for my friends?
Exclusive Rights in Copyrighted Works
1. Only the copyright owner can reproduce, sell, or distribute the
copyrighted software.
2. It is legal to copy the software from the distribution disks to the hard disk
of your computer.
3. It is legal to make an extra copy of the software in case the copy you are
using becomes damaged
4. If you give away or sell the software, you cannot legally keep a copy.
5. You cannot legally sell or give away modified or copies of the software
without permission.
131. Licensed Software
software that is protected by law stating the
constraints and limitation of the use.
software license - legal contract that defines the
ways in which you may use a computer program.
Differentiate copyright and license?
license can extend the regulations declared by the
copyright.
shrink wrap license – a license that is usually
attached in the plastic wrapper of a disk, CD or
DVD software
132. Licenses for Users
Single-user license
limits the use of the software to only one user at a time
Multiple-user license
- allows more than one person to use a particular
software package
Concurrent-use license
- allows a certain number of copies of the software to be
used at the same time
Site license
- generally allows the software to be used on any and all
computers at a specific location.
What about those software offered over the internet for free?
137. System Software
helps the computer carry out its basic operating
tasks.
Classification of System Software
1. Operating systems
2. Utility programs
3. Device Driver
4. Computer Programming Language
5. Communication software.
138. Operating System
Is essentially the master controller
for all of the activities that takes
place within a computer.
It sets the standards for all the
program and application that will be
used in a computer
140. Utility Programs
Designed to augment the operating system by
providing a way for a computer user to control the
allocation and use of hardware resources.
ex.(OS utility) Defragmenter, Diskformatting,
DiskPartitioner, Scandisk etc…
ex.(Optional Utility) Norton PartitionMagic, McAfee
Antivirus, Symantec File Recovery etc..
146. Application Software
helps the human user perform an specific task.
can be generic or be-spoke
Classification of Application Software
1. Document Production
2. Graphic Software
3. Presentation
4. Spreadsheet and Statistical
5. Database
6. Information and Reference
7. Connectivity / Communication
8. Education and Training
9. Multimedia
10.Gaming and Simulation
147. Document Production Software
group of software specific for writing software
documentation, designing a brochure, laying out
school newsletter etc
WORD PROCESSING SOFTWARE
replaced typewriters for producing documents such as report,
letter, papers and manuscript.
ex. MSWORD, Corel WORPERFECT, Lotus WORDPRO
DESKTOP PUBLISHING SOFTWARE
takes word processing software one step further by helping
you use graphic design technique to enhance the format and
appearance of a document.
ex. AdobePageMaker, Corel Ventura Microsoft Publisher
WEB AUTHORING SOFTWARE
helps you design and develop customized Web pages that you
can publish electronically on the internet.
ex. SoftSquad HotMetal, Macromedia Dreamweaver,
MSFrontpage
149. Graphic Software
group of software specific that helps you create, edit,
and manipulate images.
PAINT SOFTWARE
sometimes called image editing software, used to draw or
create paintings, sketches and other images
ex. MSPAINT, CORELDRAW etc
PHOTO EDITING SOFTWARE
includes feature specially designed to fix poor quality photos.
ex. PHOTOSHOP, Windows Imaging
3-D GRAPHICS SOFTWARE
helps you create and render three dimensional object.
ex. MAYA, 3D Studio, AutoCAD
150.
151. Presentation Software
group of software that provides all of the tools you need
for combining text, graphics, animations and sounds into
a series of electronic slides.
ex. Microsoft Powerpoint, Lotus Freelance Graphics
152. Spreadsheet and Statistical
Software
SPREADSHEET SOFTWARE
perform calculations based on numbers and formulas that you
enter.
ex. MsExcel, Lotus 123
STATISTICAL SOFTWARE
helps you analyze large sets of data to discover relationship
and patters.
ex. SPSS, JMP, and DATA DESK
Mathematical Modelling Software
provides tools for solving a wide range of math, science, and
engineering problems
ex. MathCAD and MATHEMATICA
154. Database Software
provides a flexible way to join and summarize the
information in more than one file.
155. Information Reference Software
software that provides a collection of information and a way
to access that information.
ex. Microsoft‟s Encarta, Britannica, Comptons Encyclopedia
156. Connectivity / Communication
Software
software that connects your computer to a local computer
network on the internet and provides tools that you can use
to take advantage of the information and communications
they offer.
ex. Yahoo messenger, Eudora Email, Netscape and IE
158. Multimedia Software
software that transform your computer into video
and audio station.
159. Games / Simulation Software
computer into a game station for entertainment and
learning purpose.
160. Activity 3
Assemble your virtual ideal personal computer by browsing
different parts comprises of:
1. Display Device
2. System Unit
3. 5 Input Devices (state your personal purpose)
4. 5 Output Devices (state your personal purpose)
5. If you would be installing 10 Software in your assembled
computer, what are those? (state your purpose)
6. Create the presentation about your pc.
7. Name the presentation file: Fullname_Act2
162. Data Representation
A way of converting letters, sounds, and images
into electrical signals.
Why there is a need for conversion?
A
ext: Why Digital
163. Why Are Computers Digital
Digital device works with discrete – distinct or
separate data or digits such as 1 and 0.
Analog device works with continuous data.
Digital Technology are relatively simple, dependable
and adaptable technology.
switches have only two states On or Off.
0011 – “off” “off” “on” “on”
0‟s and 1‟ are called the binary digits – “bits”
ext: Num & Data
164. Representing Numbers and Letters
Numeric data consists of numbers that might be
used in arithmetic
ie., annual income, score in exams, age.
Computers represent numeric data using the
binary number system, also called “base 2”.
Character data is composed of letters, symbols,
and numerals that will not be used in arithmetic
operations.
ie., name, address, gender, status
ext: Rep vid & Snd
165. Representing Sounds and Video
Computers must digitize colors, notes and instrument
sounds into 1‟s and 0‟s.
Digitizing is the process of converting colors and
sounds into numbers which can be represented by bits.
How does computer identify which digits are for which
file?
file header
file identification stored along with the file and can be
read by the computer, but never appears in the screen.
ext: Diff b & B
166. Quantifying Bits and Bytes
Difference between bits and bytes
bit is the smallest unit of data
Byte is equivalent to 8 bits
bit is abbreviated by lowercase b while byte is
represented by uppercase B
bit is used for transmission speed
Byte is used to denote disk capacity.
168. Lesson Objective:
At the end of this lesson, the students should be able to:
Discuss the importance of storage device in the Computer System
Differentiate memory and storage.
Differentiate Logical and Physical storage.
Differentiate the two technologies in storage such as; Magnetic Storage
and Optical Storage.
Enumerate different types of magnetic storage devices and discuss their
operation, characteristics, and advantages and disadvantages.
Enumerate different types of optical storage devices and discuss their
operation, characteristics, and advantages and disadvantages.
List and describe other special purpose storage devices.
Explain enterprise Storage Systems and Data Warehouses.
ext: Storage Perception
169. Two Storage Perceptions
1. Logical Storage
How we think data are stored in our storage
device. ie. Data inside the folder or on the
physical devices.
2. Physical Storage
Its how data are actually stored in our storage
devices.
It‟s the process being done by the computer and
the storage devices.
ext: Diff memory & SD
170. Memory vs Storage Devices
Memory (volatile)
Sometimes called primary storage
A temporary holding place for data and instructions.
More expensive yet faster than other storage devices.
Storage Devices (non-volatile)
Sometimes called secondary storage.
An area in the computer where data are permanently
stored.
Cheaper than memory chips, has higher storage
capacity yet slower data access.
171. Components Of Data Storage
Storage Media
The physical mediums on which data, information
and instructions are held.
Also known as secondary storage.
Kinds of Medium
1. Floppy Disk
2. Hard Disk
3. Mini Disk
4. CD
5. PC card/Memory card
6. Other storage such smart cards, microfilm, tapes and
other special purpose storage device.
ext: Components of DS
172. Components Of Data Storage
Storage Device
Piece of hardware that saves (writes) or retrieves
(read) data, information and instructions from
storage media.
Kinds of Devices
1. Floppy Disk Drive
2. Hard Disk Drive
3. Tape Drives
4. CD Drives
ext: Storage Basics
173. Storage Basics
Writing
Is the process of transferring data, information, and
instructions from main memory to the storage medium.
Reading
Is the process of transferring data, information, and
instructions from medium to the storage main memory.
Storage capacity
The amount of bytes of data, information and
instructions that can be kept by storage medium.
ext: Storage Tech
175. Magnetic Storage
Stores data by magnetizing microscopic particles
on the disk or tape surface.
Uses read-write head mechanism to store and
retrieve data
Read-write head mechanism in the disk drive
records and writes the magnetized particles that
represent data.
Changing or deleting of data is done by changing
the orientation of particles in the disk surface.
ext: Adv and Diadv
176. Magnetic Storage
Disadvantages
Susceptible to magnetic fields, dust, mold, smoke
particles, heat & mechanical problem with the
storage device.
Gradually lose their magnetic changes resulting in
loss of data.
Short life span (2 – 20 years)
Advantage
Newer magnetic storage disks have high storage
capacity.
Usually cheaper.(?)
ext: OpticalStorage
177. Optical Storage
Stores data as microscopic light & dark spots on the disk
surface.
Uses laser light and it is possible to see the data using high-
powered microscope.
Disadvantages
Several process for writing data
Requires software for writing data
Slower than hard disk
Advantage
Strong damage resistance
Longer life expectance (20 – 100 years)
ext: Factors
178. Factors for Choosing The Best
Storage Technology
1. Versatility
Accessibility of the medium to different device.
2. Durability
Susceptibility of the medium
3. Speed
Access Time
Average time it takes for a computer to locate data on the
medium and read it.
Measures in ms (millisecond)
Sequential Access – reads though data from beginning
Random Access – “direct access ability to jump to the requsted data.
Data Transfer Rate
Amount of data that a storage device can move from the storage
medium to the computer.
Measured in Bps (Bytes per second)
179. Factors for Choosing The Best
Storage Technology
4. Capacity
The amount of data that the storage medium
could keep.
Measured in Bytes. (MB, KB, GB, TB)
5. Cost
Amount per megabytes.
Storage Term
Term Abbreviation Approximate Size Exact Amount
Kilobyte KB or K 1 thousand bytes 1,024 bytes
Megabyte MB 1 million bytes 1,048,576 bytes
Gigabyte GB 1 billion bytes 1,073,741,824 bytes
Terabyte TB 1 trillion bytes 1,099,511,627,776 bytes
ext: FDisk
181. Floppy Disk
Small removable,
flexible magnetic
platter encased in a
plastic housing.
Made up of of a thin,
circular, flexible mylar
plastic disk with a
magnetic coating.
Also referred to as
floppies or diskettes.
ext: Data Location
182. Data Location on Floppy Disk
A disk drive track is a circular path on the
surface of a disk or diskette.
A sector is a subdivision of a track on a
magnetic disk or optical disc.
Each sector stores provides space for 512 bytes (for
magnetic disks) or 2048 bytes (for optical discs) of
user-accessible data per sector.
A cluster is the smallest logical amount of disk
space that can be allocated to hold a file.
cluster sizes range from 1 sector (512 B) to 128
sectors (64 KB)
A - track
B – Geometrical Sectors
C – Track sector
D – Clusters
ext: Mech Parts
183. Parts of Floppy Disks
Shutter
Protects the magnetic disk when not in use.
Spring
snaps the shutter closed again so no dust or fingerprints
can get onto the magnetic disk.
Magnetic disk
This round piece of plastic is coated with magnetized iron
oxide.
Hub
The metal center of the magnetic disk. The holes in the
hub fit over spindles inside the computer and hold the
disk in place while it spins.
Paper rings
glued down to the plastic housing, stay still while the disk
spins and clean the disk, removing microscopic bits of
dust.
Write-protect tab
When the hole is open, the disk is locked. Your computer
won't allow you to add anything to the disk or erase
anything from it.
Plastic flap
It functions as a simple spring that pushes the paper ring
tight against the surface of the magnetic disk.
ext: Type of FD
184. Types of Floppy Disk
3 ½ inch
Larger capacity 1.44MB
HD / DD
5 ¼ inch
Common size before
1987
Capacity – 100K and
1.2MB
No longer available
ext: Care for FD
185. Protecting Your Floppy Disk
Avoid exposure to heat, cold and magnetic fields.
Avoid exposure to dusts, smoke, or water.
Do not eject the floppy disk until the light on the front of the
drive is off and until all files on the floppy disk have been saved
and closed.
Always carry disks case or box.
Do not touch the surface of the disk.
Do not use damage disks or disks with faulty shutter to avoid
jamming in the drive.
Remember to write protect to avoid accidental erasure of data.
ext: Adv and Disadv
186. Advantages and Disadvantages
Advantages:
They are very cheap to buy
floppy disc drives are very common.
Disadvantages:
very small storage capacity
Susceptible to a lot of damages.
Slower
The access speed is about 36 KB per second.
Not all modern computers have floppy disk drives.
ext: FDD
187. Floppy Disk Drive
A device that can read
from and write on a
floppy disk
Can be external or
internal
Most personal
computers have a
floppy disk drive, in
which you insert and
remove a floppy disk
ext: Parts of FDD
188. Parts of a Floppy Disk Dive
Read/Write Heads:
Located on both sides of a diskette
used for reading and writing data on
the disk.
Spindle Motor:
engages the metal hub at the center
of the diskette, spinning it at either
300 or 360 rotations per minute
(RPM).
Stepper Motor:
move the read/write head assembly to
the proper track position. The
read/write head assembly is fastened
to the stepper motor shaft.
Circuit Board:
Contains all of the electronics to
handle the data read from or written
to the diskette.
ext: How FDD Works
189. Floppy Disks Operation
How does a floppy disk drive work?
Step 1: When you insert
the floppy disk into the
drive, the shutter moves
Step 2: When you Step 1 Step 2
to the side to expose the
initiate a disk
Step 3: If disk access
recording surface on the Step 6
access, the circuit
Step writemotor
is a instruction,
disk. 4:on the drive
board A
the circuit board
causessignals to disk
Step 5: the floppy
sends A motor
verifies whether the
to spin. movement
control
positions the
disk can be written to
of the read/write
read/write heads
or not.
Step the correct
heads The
over 6:and the disk.
read/write heads
location on the Step 5
read data from and
recording surface
write data on the
of the disk. Step 4
floppy disk.
Step 3
ext: Disk Backup
190. High Capacity Disk
A disk drive that uses disks with
capacities of 100 MB and greater
ext: HiFD
191. HiFD
HiFD™
(High-Capacity
Floppy Disk) drive
Uses a 200 MB
HiFD™ disk
Developed by
Sony Electronics,
Inc.
ext: SuperDisk
192. SuperDisk
Designed to replace
regular floppies
Can read regular
floppies
Uses a 120 MB or a
250 MB Super Disk
Developed by Imation
ext: ZipDrive
193. Zip Drive
Uses a Zip® disk that
can store 100 MB or
250 MB of data
Developed by Iomega
Corporation
They are stable,
inexpensive, and easy
to work with yet not
the fastest.
ext: MO Drive
194. MO drives
Magnetic Optic drives
You can only write to it,
when it is heated by a
laser beam to about
300 degrees Celsius
(The Curie point)
MO disks are fast,
inexpensive, and
extremely stable.
MO-technology is found
in Sony's recordable
MiniDisc.
196. What is a hard disk?
Also called a hard drive
or a fixed disk
A rigid magnetic disk
fixed permanently within
a drive unit and used for
storing computer data
Main storage device
within a computer.
“data center”
ext: Cross section
198. Characteristics of hard disk
Consists of several inflexible, circular platters that store items
electronically
A platter is coated with a material that allows items to be recorded
magnetically on its surface.
The components of a hard disk are enclosed in an airtight, sealed case to
protect them
A Hard disk spins around thousands of times per minute(rpm) inside
its metal casing, which is why it makes that whirring noise.
Capacity is determined by the number of platters.
Standard systems come with hard drives between 40Gb and 250Gb.
Usually larger, usually faster, usually cheaper and usually fixed.
Shock resistant and sealed tightly.
ext: Basic Parts
199. Basic Parts of Hard Disk
Platter
data/information is written.
Read and Write Head
read and write/information data
on the surface.
Actuator mechanism
responsible for the movement of
RW head for data access.
Spindle motor
responsible for disk rotation
ext: Operation
200. How does a hard disk work?
Step 1: The circuit
board controls the
movement of the Step 1 Step 2
Step 2: A small
head activator and a
small motor the
motor spins
plattersWhen the
Step 3: while
computer is
software requests a
running
disk access,head
Step 4: The the
read/write heads
actuator positions
determine the
the read/write
current or new the
head arms over
locationlocationdata
correct of the on Step 3
the platters to read
or write data Step 4
ext: Types
201. Types of Hard Disk
External Hard Disk Internal Hard Disk
ext: Speed
202. Measuring Speed of Hard Disk
Maximum Transfer Rate
Highest amount of data that can be transferred per second.
100Mb/s for ATA100
66Mb/s - ATA66
Spindle Rotation Speed
The rotation speed of the disk really is the basis of the other
two factors of hard disk speed.
measured in rpm (revolution/min) usually 5400rpm or 7200 rpm
Seek Time
The average time it takes for the disk to find the data you
need on the platters.
ext: Controller
203. Hard Disk Controllers
What is EIDE? What is SCSI?
Enhanced Integrated Small Computer System
Drive Electronics Interface
up to 4 HD w/ up to 8 HD
137GB/disk. Transfer rate 160 Mbps
Transfer rate 133 Mbps
ext: SATA
204. Hard Disk Controllers
SATA
Serial Advance
Technology Attachment
point to point channel
between drive.
Transfer rate up to 3GBps
ext: Adv and Dis
205. Advantages and disadvantages
Advantages
Large storage capacity
Faster Data Access
Usually fixed inside the computer so cannot get mislaid.
Cheapest/MB
Can replaced and upgraded.
Can have several hard disk on a system unit.
Disadvantages
Eventually fail
Susceptible to contaminants.
head crash occurs when read and write head touches the surface
of a platter.
Not portable.
206. Caring for your drive
1. Protect your drive from excessive jarring and
bumping.
2. Beware of static.
3. Perform periodic checks of your hard disk drive.
Disk scanning
1. Logical Scanning
2. Physical Scanning
Defragmenting
4. Place your hardware in a safe location.
5. Make Backups
208. Optical Medium
optical disk / compact
disk
A flat, round, portable,
metal storage medium that
usually is 4.75 inches in
diameter and less than
one-twentieth of an inch
thick
Common to all modern
computers
Available in a variety of
formats.
1. CD
2. DVD
ext: CD
209. Compact Disk
Compact Disk
originally used to store
music, in the form of digital
audio, and now used as a
data storage device, whence
it is called a CD-ROM.
holds 650 MB up to 700 MB
of data, instructions and
information.
Developed by Sony and
Philips in 1980, mass
produced in 1982.
A. A polycarbonate disc layer has the data
encoded by using lands and pits.
B. A reflective layer reflects the laser back.
C. A lacquer layer is used to prevent
oxidation
D. Artwork is screen printed on the top of
the disc.
E. A laser beam reads the polycarbonate
disc, reflected back, and read by the
player.
ext: How data is written
210. Compact Discs
How does a laser read data on a compact disc?
Items are stored using
Compact Compact disc
disc
Compact disc
microscopic pits Step 2 Step 31
Step label label
label
(indentations) and land
(flat areas) that are in the
middle layer of the disk
A laser light reads items
from the compact disc pit pitland land
lens lens
lens lens lens
lens
Step 1: A laser diode shines
2: If light strikes a pit,
3: Reflected light is
it scatters. If light-sensing
a light beam light strikes
deflected to atoward the
land, it is reflected digital
compact disc.
diode, which sendsback
toward of to the computer.
signals the1laser diode.
prism prism
prism
0 prism prism
prism 1
Light- Light-
Absence of reflected light is sensing sensing
read as a digital signal of 0. laser laser
laser
diode
laser laser
laser
diode
diode diode
diode diode diode
diode
ext: Types of CD
211. Types of CD
CD-ROM
Compact Disk-Read Only Memory
Read-only means you cannot write or save anything on
the disk.
CD-R
Compact-Disk Recordable
You can write only once.
CD-RW
Compact Disk-Rewritable
Allows rewriting many times.
You must have CD-RW software
and a CD-RW drive.
ext: Figures
213. DVD
Digital Versatile Disk
An extremely high
capacity compact disc
capable of storing from
4.7 GB to 17 GB
Looks just like a CD-
ROM but data,
instructions, and
information is stored in
a slightly different
manner to achieve a
higher storage
capacity
You must have a DVD-
ROM drive or DVD
player to read a DVD-
ROM.
ext: DVD Capacity
215. Capacity of DVD vs. CD
• Three storage techniques used to store DVD-ROM data
• Pits are packed closer together to make the disc more dense
• Two layers of pits are used, where the lower layer is
semitransparent so the laser can read through it to the upper layer
• Some are double-sided, which means you can remove the DVD-
ROM and turn it over to read the other side
Number of Sides 1 2
Number of Layers 1 2 1 2
Storage Capacity 4.7 GB 8.5 GB 9.4 GB 17 GB
ext: Caring for CD
216. Protecting Your Optical Disk
Do not expose the disks to excessive heat or
sunlight.
Do not touch the underside of the disks.
Do not write on the underside of the disks.
Do not stack the disks on top of one another.
Do store the disks in jewel boxes when not in
use.
Do hold disk by the edges.
ext: CD Drives
217. CD -ROM Drives
A device that reads data,
instructions and information
on a CD-ROM and CD-R.
Virtually all modern CD-ROM
drives can also play audio
CDs as well as Video CDs
and other data standards
when used in conjunction
with the right software.
ext: Spped of CD-Rom
219. CD-R/RW DRIVES
Recordable / ReWritable drives
also known as burners, writers
allow a user to create their own
CDs of audio and/or data.
great for backup purposes and
for creating your own audio CD
compilations (not to mention
other things like home movies,
multimedia presentations, etc.).
ext: DVD Drive
220. DVD-ROM
DVD drives can also read
CD-ROM drives, so you
don't usually need a
separate CD-ROM drive.
DVD drives have become
low enough in price that
there isn't much point in
purchasing a CD-ROM drive
instead of a DVD-ROM
drive.
“combo drive”
ext: DVD Speed
224. Magnetic Tape
A magnetically coated ribbon of
plastic capable of storing large
amounts of data and information at
a low cost.
A tape drive reads from and writes
data and information on a tape
Older computers used reel-to-reel
tape drives
A tape cartridge is a small,
rectangular, plastic housing for tape
used in
today‟s tape
drives
ext: Uses of MT
225. Application of Magnetic Tape
Used by business and
home users to backup
personal computer hard
disks
Used to record phone
transactions.
ext: PC Card
226. PC Card
A credit card-sized device
that adds memory, storage,
sound networking and other
capabilities to a portable pc.
Portable device allowing
mobility of large amount of
data.
Fits into a PC Card slot on a
notebook other personal
computer
ext: Other SD
