Download - Computer Fundamentals
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.
Definition
Is an electronic device that:
5 5 + 2
+ 2
5 + 2 = 7 5 + 2 = 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)
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
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.
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
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.
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.
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
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
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
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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.
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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..
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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
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.
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.
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?
The PDP-8 (1960’s)
the first successful
commercial minicomputer
built with discrete
transistors
Built 60‟s – distribute ‟65
Digital Equipment
Corporation (DEC)
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
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.
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
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
Illiac IV
one of the most
infamous
supercomputers ever
built.
256 processors –
parallel processing
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)
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
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.
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.
Components of a Computer System
Hardware
Software
End User
Physical Components of the
Computer System
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.
Next: Definition of System Unit
The System Unit
the main body of a computer.
Consist of:
motherboard
cooling fans,
internal disk drives
memory modules
expansion cards
power supply
Next: System Unit w/ labeled parts
System Unit for Laptops and PDA
keyboard and
pointing device
are on top of the
system
display is part
of the unit
Next: Motherboard
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
Next: Function of motherboard
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.
Next: Function in figure
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).
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
Next: Old Motherboard
Old Motherboard
An old IBM 8088
motherboard
Specifications
Processor Intel 8088
Speed 4.77 MHz
RAM 16K-640K
ROM Unknown
Storage
Cassette Tape,
optionally 5.25"
floppy drives, hard disks
Expansion 5 expansion slots
Bus Industry Standard Architecture (ISA)
Video
Initially CGA
(320x200x16
color, 640x200x2
color) or
monochrome (80x25 text only))
I/O Parallel, Serial
Next: Modern Mboard
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.[
Next: Figure
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
Next: Device communication
How device communicates with
processor to complete a task
input devices
output devices
Storage device
Processor
data
instruction
data
information
instruction
data
information
information
Next: Control unit
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.
Next: ALU
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
Next: Machine cycle
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
(fetches) a
command/data
from the memory
Translates
(decodes)
instructions into
signals the
computer can
understand
Carries out
(execute) the
commands listed
in the instructions
Writes (stores)
results to
memory.
Next: performance
factor
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
Next: System clock
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.
Next: Cache Memory
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.
Next: Method of processing
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
Next: Fast processor
Fast Processor
Processor
Clock
Speed
(GHz)
Price
QPI
Speed
(GT/sec)
Cache
Memory
Speed
Support
TDP Processor
Generation
Intel® Core™ i7-
965 Extreme
Edition
3.20 $999 6.4
8 MB DDR3-
1066
130
W
New Intel® Core™
Microarchitecture
(Nehalem) 45nm Intel® Core™ i7-
940 2.93 $562 4.8
Intel® Core™ i7-
920 2.66 $284 4.8
•
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?
Memory are virtual
location inside your
computer
A1 B1 C1 D1
A2 B2 C2 D2
A3 B3 C3 D3
#9 Wilson St
each location has
unique
identification called
address
01101100 10001011
01100111 10001100
the content of each
memory address is
called bytes
Next: Memory Arcihtecture
Memory And Storage Size
Term Abbreviation Approximate
Size
Exact Amount Approximat
e Pages of
Text
Kilobyte KB or K 1 thousand
bytes
1,024 bytes ½
Megabyt
e
MB 1 million bytes 1,048,576 bytes 500
Gigabyte GB 1 billion bytes 1,073,741,824
bytes
500,000
Terabyte TB 1 trillion bytes 1,099,511,627,776
bytes
500,000,000
stated in terms of the number of
bytes available for storage in the chip
or device
Next: Types
Types of Memory
Volatile
Temporary memory
Contents are lost when the
computer is turned off.
Common Type
RAM
Random Access Memory
Non-volatile
Permanent memory
Contents can be preserve
even if the computer is off.
Common Types
ROM
Read-only memory
Flash memory
CMOS
Next: RAM
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?
Types of Ram Chips
DRAM – Dynamic RAM
Needs to refresh thousands of times to keep contents
Slower
Less Expensive than SRAM
Used for large amount of temporary storage.
SRAM – Static RAM
Doesn‟t need to refresh
Faster
More expensive
Used to create the CPU‟s
cache memory.
Next: DRAM
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.
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
Next: Types of RAM
Common Types of RAM
SRAM: Does not need refreshing, but
requires several wiring connected to the transistors, used primarily for cache.
DRAM: type of memory that requires constant
refreshing.
SDRAM: Synchronous dynamic random access
memory
faster than DRAM because they are synchronous with the system clock.
the most common form in desktops today.
DDR SDRAM: Double data rate synchronous
dynamic RAM is just like SDRAM except that is has higher bandwidth, meaning greater speed.
RDRAM: Rambus dynamic random access memory use of a special high-speed data bus
called the Rambus channel that makes memory chips work in parallel to achieve a data rate of 600 MHz, or 1,600 MBps.
Speed versus heat
Next: Memory module
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
Next: DIMM and RIMM
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?
Next: SODIMM
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.
Next: Most common memory type
Other Memory Modules
Top L-R, DDR2 with heat-spreader, DDR2 without heat-spreader, Laptop
DDR2, DDR, Laptop DDR
Next: Access Time
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)
Next: How much do we need?
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?
Next: Other Primary Storage
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.
Next: Characteristics of ROM
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
Next: Types of ROM
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.
Next: PROM
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.
Next: EPROM
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.
Next: EEPROM
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.
Next: FLASH
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.
Next: FLASH
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
Next: Flash vs HDisk
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?
Next: CMOS
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.
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
Next: Buses Diagram
Computer buses
•FSB or frontside bus
is a physical
connection that
actually connects the
processor to most of
the other
components.
• usually operates at
400-MHz, with newer
systems running at
800-MHz.
• The backside bus is a
separate connection
between the processor
and the Level 2 cache.
• This bus operates at
a faster, usually at the
same speed as the
processor, so all that
caching works as
efficiently as possible. •PCI bus
• 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
bus. Next: Types
Types of Buses
Internal Buses also known as the system bus
or the local bus.
reside on the motherboard and connects the processor to other devices on the main circuit board. Data bus – used to send and
receive data between devices
Address bus – connects processor and ram, responsible for addressing of requests.
External Buses
also known as expansion
bus.
connect external devices
into the main circuit
board.
used by keyboard, mouse,
monitor and printer
Next: Factors
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
Next: Standard Bus
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
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
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
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.
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
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.
A PCI Express x16 slot
A PCI Express x1 slot
Specs for each generation per lane
Clock
speed
Transfer
rate Data rate
1.x 1.25 GHz 2.5 GT/s 250 MB/s
2.0 2.5 GHz 5 GT/s 500 MB/s
3.0 4 GHz 8 GT/s 1 GB/s
Specs for each generation per lane
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
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.
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.
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.
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?
Next: Port Diagram
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.
Next: Firewire
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.
Next: Ethernet
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.
Next: Serial
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.
Next: Parallel
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.
Next: PS/2
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
Next: VGA
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.
Next: DVI
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).
Next: SCSI
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.
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.
Next: Type: Internal
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.
Next: Type External
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.
Next: Pow Supp
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.
Next: Connector
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.
Next: Digital Rep
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
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.
CLASSIFICATION of SOFTWARE
Software are classified based on how they could
be used.
1. Copyrighted Software
2. Licensed Software
3. Shareware
4. Freeware
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.
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
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?
Freeware
also refers to as public domain software
put in the public domain to be used by any person
without limitations
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.
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
Operating Systems
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..
The system software that helps the computer control a peripheral device.
Device Driver
Computer Programming Language
Allows a programmer to write a program using English-like instructions.
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
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
Document Production Software
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
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
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
Database Software
provides a flexible way to join and summarize the information in more than one file.
Information Reference Software
software that provides a collection of information and a way
to access that information.
ex. Microsoft‟s Encarta, Britannica, Comptons Encyclopedia
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
Education and Training Software
software that helps the user practice new skills.
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
Data Representation
A way of converting letters, sounds, and images
into electrical signals.
Why there is a need for conversion?
A
Next: Why Digital
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”
Next: Num & Data
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
Next: Rep vid & Snd
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.
Next: Diff b & B
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.
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.
Next: Storage Perception
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.
Next: Diff memory & SD
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.
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.
Next: Components of DS
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
Next: Storage Basics
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.
Next: Storage Tech
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.
Next: Adv and Diadv
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.(?)
Next: OpticalStorage
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)
Next: Factors
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)
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 Next: FDisk
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.
Next: Data Location
Data Location on Floppy Disk
A - track
B – Geometrical Sectors
C – Track sector
D – Clusters
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)
Next: Mech Parts
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.
Next: Type of FD
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
Next: Care for FD
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.
Next: Adv and Disadv
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.
Next: FDD
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
Next: Parts of FDD
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.
Next: How FDD Works
Step 6: The
read/write heads
read data from and
write data on the
floppy disk.
Step 6
Step 5: A motor
positions the
read/write heads
over the correct
location on the
recording surface
of the disk.
Step 5
Step 4: A motor
causes the floppy disk
to spin.
Step 4
Step 3: If disk access
is a write instruction,
the circuit board
verifies whether the
disk can be written to
or not.
Step 3
Step 2: When you
initiate a disk
access, the circuit
board on the drive
sends signals to
control movement
of the read/write
heads and the disk.
Step 2
Step 1: When you insert
the floppy disk into the
drive, the shutter moves
to the side to expose the
recording surface on the
disk.
Step 1
Floppy Disks Operation
How does a floppy disk drive work?
Next: Disk Backup
HiFD
HiFD™
(High-Capacity
Floppy Disk) drive
Uses a 200 MB
HiFD™ disk
Developed by
Sony Electronics,
Inc.
Next: SuperDisk
SuperDisk
Designed to replace
regular floppies
Can read regular
floppies
Uses a 120 MB or a
250 MB Super Disk
Developed by Imation
Next: ZipDrive
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.
Next: MO Drive
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.
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”
Next: Cross section
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.
Next: Basic Parts
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
Next: Operation
Step 4: The head
actuator positions
the read/write
head arms over the
correct location on
the platters to read
or write data Step 4
Step 2: A small
motor spins the
platters while the
computer is
running
Step 2
Step 3: When
software requests a
disk access, the
read/write heads
determine the
current or new
location of the data
Step 3
Step 1: The circuit
board controls the
movement of the
head activator and a
small motor
Step 1
How does a hard disk work?
Next: Types
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.
Next: Controller
Hard Disk Controllers
What is EIDE?
Enhanced Integrated
Drive Electronics
up to 4 HD w/
137GB/disk.
Transfer rate 133 Mbps
What is SCSI?
Small Computer System
Interface
up to 8 HD
Transfer rate 160 Mbps
Next: SATA
Hard Disk Controllers
SATA
Serial Advance
Technology Attachment
point to point channel
between drive.
Transfer rate up to 3GBps
Next: Adv and Dis
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.
Next: Protection
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
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
Next: CD
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. Next: How data is written
Step 3: Reflected light is
deflected to a light-sensing
diode, which sends digital
signals of 1 to the computer.
Absence of reflected light is
read as a digital signal of 0.
Step 1: A laser diode shines
a light beam toward the
compact disc.
Step 2: If light strikes a pit,
it scatters. If light strikes
land, it is reflected back
toward the laser diode.
Compact disc
label
Compact disc
label
lens lens
prism prism
laser
diode
laser
diode
Step 1
Compact disc
label
lens lens
prism prism
laser
diode
laser
diode
Items are stored using
microscopic pits
(indentations) and land
(flat areas) that are in the
middle layer of the disk
A laser light reads items
from the compact disc
Compact Discs
How does a laser read data on a compact disc?
Step 2
Compact disc
label
lens lens
prism prism
laser
diode
laser
diode
pit land
Step 3
Compact disc
label
lens lens
prism prism
laser
diode
laser
diode
Light-
sensing
diode
Light-
sensing
diode
0 1
pit land
Next: Types of CD
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.
Next: Figures
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.
Next: DVD Capacity
Capacity of DVD disks
Designation Sides Layers
(total)
Diameter Capacity
(cm) (GB) (GiB)
DVD-R SS SL (1.0) 1 1 12 3.95 3.68
DVD-R SS SL (2.0) 1 1 12 4.70 4.37
DVD-RW SS SL 1 1 12 4.70 4.37
DVD+R SS SL 1 1 12 4.70 4.37
DVD+RW SS SL 1 1 12 4.70 4.37
DVD-R DS SL 2 2 12 9.40 8.75
DVD-RW DS SL 2 2 12 9.40 8.75
DVD+R DS SL 2 2 12 9.40 8.75
DVD+RW DS SL 2 2 12 9.40 8.75
DVD-RAM SS SL 1 1 8 1.46 1.36*
DVD-RAM DS SL 2 2 8 2.65 2.47*
DVD-RAM SS SL (1.0) 1 1 12 2.58 2.40
DVD-RAM SS SL (2.0) 1 1 12 4.70 4.37
DVD-RAM DS SL (1.0) 2 2 12 5.16 4.80
DVD-RAM DS SL (2.0) 2 2 12 9.40 8.75*
Next: Capacity DVD vs CD
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
Next: Caring for CD
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.
Next: CD Drives
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.
Next: Spped of CD-Rom
Transfer speeds for CD-ROM
Data Transfer Speeds
Transfer Speed KB/s Mb/s
1x 150 1.2288
2x 300 2.4576
4x 600 4.9152
8x 1200 9.8304
10x 1500 12.2880
12x 1800 14.7456
20x 3000 24.5760
32x 4800 39.3216
36x 5400 44.2368
40x 6000 49.1520
48x 7200 58.9824
50x 7500 61.4400
52x 7800 63.8976
56x 8400 68.8128
72x 10800 88.4736
Next: CD-R/RW Drive
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.).
Next: DVD Drive
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”
Next: DVD Speed
DVD Drive Speed
DVD drive speeds
Drive speed Data rate ~Write time (min)[24]
(Mbit/s) (MB/s) (MiB/s) SL DL
1× 10.80 1.35 1.29 61 107
2× 21.60 2.70 2.57 31 54
2.4× 25.92 3.24 3.09 25 45
2.6× 28.08 3.51 3.35 23 41
4× 43.20 5.40 5.15 15 27
6× 64.80 8.10 7.72 10 18
8× 86.40 10.80 10.30 8 13
10× 108.00 13.50 12.87 6 11
12× 129.60 16.20 15.45 5 9
16× 172.80 21.60 20.60 4 7
18× 194.40 24.30 23.17 3 6
20× 216.00 27.00 25.75 3 5
22× 237.60 29.70 28.32 3 5
24× 259.20 32.40 30.90 3 4
Next: DVD RW
DVD RW
Recordable /
Rewritable Drives
Could read almost all
optical media.
Used for backup large
amount of files
(multimedia).
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
Next: Uses of MT
Application of Magnetic Tape
Used by business and
home users to backup
personal computer hard
disks
Used to record phone
transactions.
Next: PC Card
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
Next: Other SD
Other Type of Storage
Storage Capacity Device Name Type, Use
Clik! Disk
CompactFlash
Microdrive
SmartMedia
40 MB
2 to 256 MB
1 GB
2 to 128 MB
Cartridge Digital cameras, notebook
computers
Memory Card Digital cameras, handheld
computers, notebook
computers, printers, cellular
telephones
Memory card Digital cameras, handheld
computers, music players,
video cameras
Memory Card Digital cameras, handheld
computers, photo printers,
cellular telephones
Next: Microfilm
Microfilm
A roll of film on which
a printed book, journal,
newspaper, or other
publication has been
reduced in size.
Next: Microfiche
Microfiche
A microfiche is a flat film 105 x 148 mm in size that carries a matrix of micro images.
Office size papers or magazine pages require a reduction of 24 or 25 for storage.
Microfiche are stored in open top envelopes which are put in drawers or boxes as file cards, or fitted into pockets in purpose made books.
Next: Life Span
Lesson Objective:
At the end of this lesson the, students should be
able to:
Identify the required components for
communication. Identify the uses of communication.
Recognize the communication devices.
Differentiate the types of transmission media.
List the characteristics of transmission.
Computer Communication
Transfer of data, information and instructions
between two or more computers or devices.
Components of Communication System
Sending device Initiates instructions for
data/information/instructions
transmission
Receiving device Accepts transmission of
data/information/instructions.
Communication Device Connects sending device to the
receiving device
Communication Channel The transmission media on which
data/information/instruction travel.
Next: Cat of Channel
Communication Channel
The transmission media on which data,
information, and instruction travel.
carry the data from one computer to another.
Two Categories of Communication Channel
1. Physical Connections
solid or tangible medium to connect sending and
receiving devices.
2. Wireless Connections
Use intangible (air) substance to connect sending and
receiving devices.
Next: Physical
Physical Connections
Telephone Lines
consists of twisted-pair
cable which is made up of
hundreds of copper wires.
plugged in a wall
mounted jack.
use to be the standard
medium for voice and
data transmission.
Figure of Telephone Cable
Next: Coax
Physical Connections
Coaxial Cable
a high-frequency
transmission cable,
replaces the multiple
wires of telephone with a
single solid-copper core.
80 times faster than the
twisted-pair cable.
used to deliver tv signal
and pc network
connection.
Figure of Coaxial Cable
Next: Fiber
Physical Connections
Fiber-optic cable transmits data as pulses of light
through tiny tubes of glass or plastic.
26,000 times faster the transmission capacity of the twisted-pair.
lighter and more reliable at data transmission compared to coaxial.
rapidly replacing twisted-pair cable telephone lines.
Figure of Fiber-Optic Cable
Next: Wireless
Wireless Connection
Infrared
uses infrared light waves
to communicate over
short distances.
line-of-sight
communication
linear transmission
Use for transmitting data
from portable devices to a
computer.
broadcast radio
Broadcast Radio uses radio signal to
communicate with wireless devices.
used by cellular phone technology to place call/ connect to the Internet.
Web-enabled devices must follow WI-FI standard. Wireless Fidelity – communication
standard widely used to connect computers to each other and to the Net.
Next: Micrwave
Wireless Connection
Microwave uses high-frequency radio waves
than can only travel in straight line.
requires microwave stations with microwave dishes or antenna for long distance relay of data.
good for sending data; building to building or,
large college campuses. Bluetooth
Microwave
Bluetooth
short-range wireless
communication of
approximately 33 feet.
does not require line-of-
sight except metallic
barrier.
becoming standard for
connecting various
communication devices.
NextSattelite
Wireless Connection
Satellite uses satellite orbiting about 22,000
miles above the earth as microwave relay stations. Offered by Intelsat, International
Satellite Consortium owned by 114 government forming a worldwide communication system.
Could amplify and relay signals from one transmitter on the ground to another.
Used to send and receive
large volumes of data.
sending data to satellite is
called Uplink
receiving data to satellite is
called Downlink
can be interrupted by bad
weather.
Popular application
includes satellite tv and
GPS.
Next: App of Comm.
Uses of Computer Communication
1. E-mail
2. Voice Mail
3. Smart Phone
4. Instant Messaging
5. Telecommuting
6. Video Conferencing
7. Groupware
8. Global Positioning System (GPS)
9. Bulletin Board System (BBS)
10.E-Commerce
Short for electronic mail transmission of electronic documents (messages and files) via computer
networks.
allows you to insert pictures, audio, video and animations.
allows multiple recipients
Voice Mail
E-mail system that
supports audio.
Computer voice mails are converted into digital form so that it can be stored in the voice mailbox in the computer.
Features of Voice Mail Program detailed log record of all calls (date, time, callerID)
messages are playable any time, can be forwarded, accessed via internet or saved for future use.
Smart Phone
Wireless telephone set that
allows sending of email, web
browsing, fax, intercom,
personal information
management, online banking
and remote data transfer
between phone and pc.
Function as portable office.
Instant Messaging
Real-time communication over the Internet that allows you to exchange messages and files with one or more people. works like phone except that you type.
new IM allows voice and video conferencing
Telecommuting
Allows employees to work at home, on a computer and then transmitting finished work to office via any available communication medium. teleporting
Advantages: reduces pollution.
saves gasoline.
less congested commuting environment.
Video Conferencing
Allows communication between two or more people to transmit real-time video and audio signal using computer. uses video device (pccam) but usually associated
with audio
used for business, socialization, or simple communication
Groupware
Class of software that
allows a group
attached to a local
network to organize
their activities.
Groupware Operations scheduling meetings and
allocating resource
password protection for documents
telephone utilities
electronic newsletters
file distribution
Global Positioning System
A navigation system consisting of one or more earth-based receivers and satellites, the signal of which are analyzed to determine location. GPS receiver
small, hand-held device with screen displaying the user‟s location on a map used to accept and analyze satellite signals.
BBS
Bulletin Board System is an electronic message centre that serves specific
interest group.
allows reviewing of and responding to posted messages
currently known as “forum”
E-Commerce
Electronic Commerce
commonly known as (electronic marketing) buying and selling products
electronically.
Common Types B2B
Business-to -business
B2C Business-to-consumer
popular example:
e-bay and Amazon.com
Next: Network
Network
What is a Network
Group of computer systems connected together.
connected using communication devices and
physical or wireless transmission media.
Next: Types
Types of Network
1. LAN – Local Area
Network
connection of computers
usually in one
geographically situated
in one area.
usually spans less than a
mile and are owned and
operated by individual
organizations.
used for file and
resources sharing across
short distances.
Next: MAN
Types of Network
2. MAN – Metropolitan-Area Network spans distances up o 100
miles.
Typically use wireless infrastructure or Optical fiber connections to link office buildings that are located throughout the city.
typically owned by group of organizations who jointly owned and operate the network
Next: WAN
Types of Network
3. WAN
Wide-Area Network
countrywide and worldwide
networks.
provides regional access
that spans more than 100
miles.
use microwave relays and
satellites to reach users
over long distances.
Next: Net arch
Network Architecture
Describes how a network is arranged and how
resources are coordinated and shared.
Describes the physical arrangement of the
network.
encompasses different network specifications
including configurations and strategies
how information and resources are shared.
Topology
Refers to the geometric arrangement of a computer
system.
Next: Topology
Common Topologies
1. bus
2. ring
3. star
4. tree
5. mesh / fully connected Computer network can be
one of one or combination of
topologies.
Next: BUS
BUS
Devices are connected
to a central cable
called the bus or
backbone.
Each device handles
its own communication
control through the
bus.
Devices checked for
any information
intended for them.
Advantages and Disadvantages of
Bus Topology
Advantages relatively inexpensive yet easy to
install for small network.
sharing data stored on different computers.
Failure, adding, and removing of node from the network, does not affect other nodes
Disadvantages suitable for small network with few
computers
Entire network fails if there is any problem in the central cable
Difficult to identify the problem if the entire network shuts down.
Next: Ring
Ring
Devices are connected
to one another in the
shape of closed loop.
no central file server or
computer.
messages are passed
along the ring until it
reached its destination.
least frequently used.
mainframe mainframe
Advantages and Disadvantages of Ring
Topology
Advantages It is less expensive than star
topology.
Nodes can be easily added or removed.
they offer high bandwidth
Cable faults are easily located, making troubleshooting easier
Disadvantages Expansion to the network can
cause network disruption.
If a node fails, it affects the entire network
Next: Star
STAR
Devices are connected
to a central hub.
central hub – a device
that typically acts as a
host computer or file
server of the network.
Control is maintained
by polling
polling is a network
process of asking
whether it has a
message to send.
Advantages and Disadvantages
of Star Topology
Advantages supports time-sharing system.
Easy to install and manage.
You can easily add and remove nodes to and from the network without affecting the network.
Disadvantages bottlenecks can occur because
all data must pass through the hub.
If Hub fails the entire network is failed.
May require hub upgrade.
Next: Tree
TREE
Combines
characteristics of
linear bus and star
topologies.
Consists of groups of
star-configured
workstations connected
to a linear bus
backbone cable.
Advantages and Disadvantages of
Tree Topology
Advantages: Point-to-point wiring for individual
segments.
Supported by several hardware and software venders.
Disadvantages: Overall length of each segment is
limited by the type of cabling used.
If the backbone line breaks, the entire segment goes down.
More difficult to configure and wire than other topologies.
Next: Mesh
Mesh
Devices are connected with many redundant interconnections between network nodes.
point-to-point connection between every device on the network. Assuring continuous
connectivity between devices
Advantages and Disadvantages of
Mesh Topology
Advantages: Provides redundant paths
between devices
Failure of one node doesn‟t affect other node.
Expandable.
Disadvantages: Requires more cable than
the other LAN topologies.
Complicated implementation.
Next: Consideration
Considerations When Choosing a
Topology:
Money. A linear bus network may be the least
expensive way to install a network; you do not
have to purchase concentrators.
Length of cable needed. The linear bus network
uses shorter lengths of cable.
Future growth. With a star topology, expanding a
network is easily done by adding another
concentrator.
Cable type. The most common cable in schools
is unshielded twisted pair, which is most often
used with star topologies.
Communication Devices
hardware devices capable of transmitting data, information and instructions between a sending device and a receiving device. modems
network cards
wireless access points
gateway
routers
hub
bridge
repeater
switch
Modems
short for modulator/demodulator
a communication device that converts one form of a signal to another that is suitable for transmission over communication circuits
analog to digital / digital to analog
Types of Modem
Dial up modems usually comes in a form of an adapter card where a telephone cord is
connected.
uses the telephone lines.
ISDN & DSL sends and receives digital signal
Network Cards
also known as NIC, Network Interface Card
an adapter or PC card that enables a computer
device to access a network.
Wireless Access Points
acts as a central communication device, allowing
devices to transfer data information and
instructions wirelessly,
fitted with antenna to enhance transmission of
receiving signals
Gateway
A network point that acts as an entrance to
another network.
controls traffic within a company network or at a
local Internet Service Provider.
Routers
communication devices that can send packets
(blocks of data) to the correct LAN segment to
take them to their destination.
ensures that data are transmitted to the correct
devices in the network.
HUB
a device to which all clients and servers are wired.
it has the ability to regenerate the data bits on the
output side in order to maintain a strong signal.
Bridge
a device that connects a local network to another
local area network and passes packets between
two network segments that use the same
communication protocol.
Repeater
a device that extends communications over long
distances.
A hub switch or router can operate as a repeater.
Switch
A switch is a device that channels incoming data
from any multiple input ports to the specific output
port that will take the data toward its intended
destination.
Activity 4
Design a network architecture using the following specifications: Building 1 and Building 2 – 250 miles apart.
Building 1 consists of 5 departments. each department consists of 5 computers connected in star topology.
Building 2 consists of 8 departments. each department consists of 4 computers connected in bus topology.
Show using a block diagram: the set up of network for building 1
the set up of network for building 2
the set up of network for building 1 and 2
Describe the Type of Network used
Describe the Type of Communication Channel used
Describe the Types of Communication Device used.
Assignment: Activity 3
What is communication device? Search for the following communication devices:
1. modems and types
2. network cards
3. wireless access points
4. gateway
5. routers
6. hub
7. bridge
8. repeater
9. switch a) Define each of them
b) discuss their function
c) attached pictures
d) list down their advantages and disadvantages
Should be hand-written
and compiled in a yellow
paper with picture pasted
on it.
Learning Objective:
After this Lesson the students should be able to:
Identify the different types of data problem
Enumerate the causes of data problem.
Categorize different destructive or harmful
programs.
List the effects of destructive programs.
Enumerate ways on how to protect and prevent
destructive files from destroying our computer files.
DATA PROBLEM
Types of Data Problem
Lost data or Missing Data – consists of data that
is inaccessible, usually because of accidental
removal.
Stolen data – not necessarily missing, but has
been accessed or copied without authorization.
Inaccurate data – consists of data that is not
accurate because it was entered incorrectly, it
was deliberately or accidentally altered, or it was
not edited to reflect current facts.
Causes of Data Problem
1. Operator Error – refers to a mistake made by a computer user.
2. Power Problem
Power Failure – complete loss of power.
Power Spikes – is a sudden increase in power.
Power Surge – sudden increase in power, longer than spike.
Electronically Protective Device 1. UPS – uninterruptible power supply, designed to provide
enough power to keep your computer running momentarily.
2. surge strip – protect computer and modem from from power spikes and surges, but does not contain a battery to prolong the power of your computer.
3. AVR – Automatic Voltage Regulator, protect the circuit from spikes or surges by regulating the output power.
Causes of Data Problem
3. Hardware Failure – is data problem caused by
peripheral breakdown.
4. Fires, Floods and Other Disasters.
5. Viruses and Other Malicious Programs.
Computer Crime
an illegal action in which perpetrator uses a special knowledge of computer technology.
Computer Criminals can be:
1. Employees – largest category with the easiest access to computers.
2. Outside Users – clients/suppliers who has access to computer system.
3. Hackers and Crackers
Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it
Crackers do the same thing but for malicious purpose only.
4. Cyberpunks
are people who creates and spreads annoying program on the internet.
5. Organized Crime – cyber fraud
6. Terrorists – potentially damage navigation system and government communication system.
Programs they created
Malware short for malicious
software specifically designed to
damage or disrupt a computer system
Most common Malware 1. Viruses
2. Worms
3. Trojan Horses
Programs they created
Spyware designed to intercept or take
partial control of a computers operation without the informed consent of that machine‟s operator.
gathers users information
records keystrokes, history, passwords, and other information.
hard to detect.
Programs they created
Adware
software that
periodically pops up
advertisements on a
user‟s computer.
sometimes integrated
into or bundled with a
program.
Programs they created
Spam e-mails that are not
requested.
also known as “junkmails”
advertising strategy.
How do companies know our e-mail addresses?
Computer Virus
a program that attaches itself to a file, reproduces itself, and spreads to other files. activate when its associated file is executed. Virus deliver its payloads – „ultimate mission‟
Types of Virus file virus
virus that attaches itself to an application program such as game and application programs.
boot sector virus infects the system files that your computer uses
every time you turn it on.
macro virus infects a set of instructions called macro.
macro – is essentially a miniature programs that usually contains legitimate instructions to automate document and worksheet production.
Computer Virus
Causes of Computer Virus Infection Exchanging infected storage
devices. Downloading of illegitimate file,
software or programs. Copying and opening file, software,
or programs from unreliable sources. (file sharing)
Opening or downloading e-mail attachments from unknown sender.
Using storage device from an infected computer. effect
Effects of Computer Virus Infection It can corrupt or destroy
data.
Disrupt computer operations.
Could crash computer system
Symptoms of Computer Virus
Infection
Displaying of vulgar, embarrassing, or annoying
messages.
Developing unusual visual or sound effects.
Difficulty accessing of files or mysteriously
missing of files.
Changes in performance.
Unexpected reboots.
Changes in file size especially executable files.
Trojan Horse (is it a virus?)
a computer program that appears to perform one function while actually doing something else. notorious for stealing passwords using
a keyloggers keylogger – a type of program that
records your keystrokes. diff bet virus and trojan
Difference between Trojan and Virus Trojan might contain virus. Trojan is not designed to make a copy
of itself. Trojan are standalone programs.
„crackers delight‟
Causes, Symptoms and Effects
Causes of Trojan Horse Infection Downloading, copying and opening software or programs from
unreliable sources.
Opening or downloading e-mail program attachments from unknown sender.
Entering password and username to illegitimate login screen on a network.
Symptoms of Trojan Horse Infection Difficulty opening program or mysteriously missing of executables. Changes in performance. Appearance of unknown programs. Alterations of password protected accounts.
Effects of Trojan Horse It can steal passwords or breach one system. It can corrupt or destroy data.
Time Bomb and Logic Bomb
Time Bomb a computer program that
stays into your computer system undetected until it is triggered by a certain event in time. It could reside in your
computer without discovery. Might contain virus
Logic Bomb a computer program that
is triggered by the appearance or disappearance of specific data.
Causes, Symptoms and Effect
Causes of Time Bomb and Logic Bomb Downloading, copying and opening software or programs
from unreliable sources.
Opening or downloading e-mail program attachments from unknown sender.
Logic Bomb on the other hand can be created by a company programmer/employee.
Symptoms of Time and Logic Bomb
Difficulty opening program or mysteriously appearance of
executables files.
Changes in performance.
For Time Bomb: Lost or Missing Data.
Effect of Time or Logic Bomb
It can corrupt or destroy data.
Destroy computer system
Worms
Worm (is it a virus?) a program designed
to enter a computer system – usually a network – through security “holes”.
has the ability to copy itself from machine to machine.
302
Causes and Effects
Causes of Worm
Opening or downloading e-mail program attachments from unknown sender.
Accessing files from worm infected network server.
Effects of Worm
Filled up storage device.
Affects computer performance.
Disrupting access to file, programs, Web pages, and other services provided by the network.
Designed to attack network servers.
Protection and Prevention
Use virus monitoring and cleaning software.
Use worm detecting and cleaning software.
Observe the status of files and performance of your computer.
Create backup of database or records.
Avoid downloading files / programs from illegitimate sites.
Avoid opening email attachments from unknown sender.
Avoid opening files/programs from unreliable sources.
If using storage device to other computer, make sure it is using anti-virus software.
Never use your password and username to unknown logins.
Use firewall. firewall – a combination of hardware and software that provides security system,
usually to prevent unauthorized access from outside to an internal network or intranet.
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Melissa
The Melissa worm, also known as "Mailissa",
"Simpsons", "Kwyjibo", or "Kwejeebo", is a mass-
mailing macro virus, hence leading some to
classify it as a computer worm.
History
Written by David L. Smith in Aberdeen Township,
New Jersey, and named after a lap dancer he
encountered in Florida.
First found on March 26, 1999, Melissa shut down
Internet mail systems that got clogged with infected
e-mails propagating from the worm.
Melissa was not originally designed for harm, but it
overflowed servers and caused unplanned problems
Worm specifications
Melissa can spread on word processors Microsoft
Word 97 and Word 2000. It can mass-mail itself
from e-mail client Microsoft Outlook 97 or Outlook
98.
If a Word document containing the virus, either
LIST.DOC or another infected file, is downloaded
and opened, then the macro in the document runs
and attempts to mass mail itself.
When the macro mass-mails, it collects the first
50 entries from the alias list or address book, and
sends it to the e-mail addresses of those names.
Variants
Melissa.U This variant deletes critical files. Before deleting the files, it strips
them of their archive, hidden, and read-only attributes.
Melissa.V It uses Microsoft Outlook, and tries to send itself to the first 40
addresses in address book. subject line: "My Pictures (<Username>)", where <Username> is the
name to whom the sender's copy of Microsoft Word is registered.
payload is triggered immediately when infected attachment is opened.
Once complete, it beeps three times and displays a message : "Hint: Get Norton 2000 not McAfee 4.02".
Melissa.AO
This is what the e-mails from this version contain:
Subject: Extremely URGENT: deceit
To All E-Mail User - <current date>
Attachment: <Infected Active Document>
Body: This announcement is for all E-MAIL user. Please take note that our E-Mail Server will down and we recommended you to read the document which attached with this E-Mail.
Melissa.AO's payload occurs at 10 a.m. on the 10th day of each month. The payload consists of the worm inserting the following string into the document: "Worm! Let's We Enjoy."
Sub7Trojan
Sub7 is the most famous Trojan/backdoor application ever. It has been a hacker‟s
perennial favorite since the late 90s.
When Sub7 is installed on the PC, a backdoor is created attackers are notified, and this is from here that the real fun begins.
310
I Love You Virus
The ILOVEYOU virus, also known as VBS/Loveletter and Love Bug virus, is a computer virus written in VBScript.
Description
The virus arrived in e-mail boxes on May 4, 2000, with the simple subject of "ILOVEYOU" and an attachment "LOVE-LETTER-FOR-YOU.TXT.vbs". Upon opening the attachment, the virus sent a copy of itself to everyone in the user's address list, posing as the user.
Two aspects of the virus made it effective: It relied on social engineering to entice users to open the
attachment and ensure its continued propagation.
It exploited the weakness of the email system design that an attached program could be run easily by simply opening the attachment;
Spread
From Philippines across West
Used mailing lists as source of targets
Pretended to be from an acquiantance so might be
considered "safe”.
Few users to open the file was all it took and
generated thousands and thousands of e-mails
that would cripple e-mail systems under their
weight
Effects
It began in the Philippines on May 4, 2000, and spread across the world in one day (traveling from Hong-Kong to Europe to the United States), infecting 10 percent of all computers connected to the Internet and causing about $5.5 billion in damage.
The Pentagon, CIA, and the British Parliament had to shut down their e-mail systems to get rid of the virus, as did most large corporations.
This particular malware caused widespread outrage, making it the most damaging virus ever. The virus overwrote important files, as well as music, multimedia and more, with a copy of itself. It also sent the virus to everyone on a user's contact list.
This particular virus only affected computers running the Microsoft Windows operating system.
Detection
Narinnat Suksawat, a 25-year-old Thai software
engineer, was the first person to write software that
repaired the damage and release it to the public on
May 5, 2000, 24 hours after the worm had spread.
"Rational Killer", the program he created, removed
virus files and restored the previously removed
system files so they again functioned normally.
Two months later, Narinnat was offered a senior
consultant job at Sun Microsystems and worked
there for two years.
UK company MessageLabs shot to fame when
their anti-virus software, Skeptic, proactively
detected the attachment as malware, thus
automatically protecting all of their customers.
The first copy intercepted by them was stopped at
00:43:26 4 May 2000 UTC, and originated from an
email address in the Philippines, going to an email
address in the UK. It is likely that the email was
from one of the first few rounds of replication of the
virus.
Variants
Attachment: LOVE-LETTER-FOR-YOU.TXT.vbs Subject Line: I LOVEYOU Message Body: kindly check the attached LOVE LETTER coming from me.
Attachment: mothers day.vbs Subject Line: Mothers Day Order Confirmation Message Body: We have proceeded to charge your credit card for the amount of $326.92 for the mothers day diamond special. We have attached a detailed invoice to this email. Please print out the attachment and keep it in a safe place.Thanks Again and Have a Happy Mothers Day! [email protected]
Variants
Attachment: virus_warning.jpg.vbs
Subject Line: Dangerous Virus Warning
Message Body: There is a dangerous virus
circulating. Please click attached picture to view it
and learn to avoid it.
Attachment: protect.vbs
Subject Line: Virus ALERT!!!
Message Body: a long message regarding
VBS.love letter.A
Variants
Attachment: Virus-Protection-Instructions.vbs Subject Line: How to protect yourself from the IL0VEYOU bug! Message Body: Here's the easy way to fix the love virus.
Attachment: Arabian.TXT.vbs Subject Line: Thank You For Flying With Arab Airlines Message Body: Please check if the bill is correct, by opening the attached file
Attachment: Picture.vbs Subject Line: Is this you in this picture? Message Body: Is this you in this picture?
Legislative aftermath
As there were no laws in the Philippines against virus-
writing at the time, on August 21, 2000, the prosecutors
dropped all charges against Onel A. de Guzman in a
resolution signed by Jovencito Zuno. The original charges
brought up against de Guzman dealt with the illegal use of
passwords for credit card and bank transactions. The
Philippines E-Commerce Law (Republic Act No. 8792),
passed on June 14, 2000, laid out penalties for
cybercrime. Under the law, those who spread computer
viruses or otherwise engage in cybercrime (including
copyright infringement and software cracking) can be fined
a minimum of 100,000 pesos (about USD$2,000), and a
maximum commensurate with the damage caused, and
imprisoned for six months to three years.
Anti-virus Software
Antivirus Software sometimes referred to as a virus detection software,
examines the files stored on a disk to determine whether they are infected with a virus, then disinfects the disk, if necessary.
Virus Detection Techniques Change in length or size detection.
Checksum calculation. Checksum – a number that is calculated by combining the
binary values of all bytes in a file.
Virus Signature checking. Virus signature – is a unique series of bytes that can be used to
identify a known virus, much as fingerprint is used to identify an individual.
Virus Checking Method Automatic – background monitoring
Manual – scheduled or manual checking.
About Antivirus:
When Should we use Antivirus Software?
all the time
How often should we update?
destructive programs variants are unleashed almost everyday.
Download various definitions as often as every other day.
How reliable is antivirus software?
Multi-partite virus – are able to infect multiple types of targets.
Polymorphic viruses – mutate to escape detection by changing their signatures.
Stealth viruses – remove their signatures from a disk-based file and temporarily conceal themselves in memory.
Data Backup
Why Do We Need Backup?
helps recover data that‟s been wiped out be
operator error, viruses, or hardware failures.
How to make backup?
Backup is a copy of one or more files that has been
made in case the original files become damaged.
usually stored in a different medium from the original
files.
Depends on your backup software.
Data Restoration
Data Restoration is the process of copying files
from a backup to the original storage medium or its
replacement.
Restoring data is as simply as copying from backup
medium to your original storage, and as completed
as performing series of steps based on your backup
technology.
Backup Plan
1. Decide how much of your data you want, need, and can afford to back up
2. Create a realistic schedule for making backups.
3. Make sure you have a way to avoid backing up files that contain viruses.
4. Find out what kind of boot disks you might need to get your computer up and running after a hard disk failure or boot sector virus attack.
5. Make sure you can test your restore procedure so that you can successfully retrieve the data you‟ve backed up
6. Find a safe place to store your backups.
7. Decide what kind of storage device you‟ll use to make backups.
8. Select software to handle backup need.
Types of Backup
Full-system backup
contains a copy of every program, data, and system file on a
computer.
Advantage:
Easy restoration of system
Disadvantage
Takes a lot of time
requires large capacity storage backup device
Selective Backup
contains only your most important data file.
Advantage
easy to restore
Disadvantage
You must manually reinstall all your software and programs
Backup Devices
Factors in selecting a backup device 1. Value of your data
2. Current equipment
3. Budget
What is the easiest way to back up important data?
Through the use of CD or DVD.
Disadvantage
Writing process is slow
Requires special backup software.
Monitor the backup process
Switch disks occasionally
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http://erwinglobio.multiply.com/