Dasar Teknologi Informasi -...

10-Mei-12 @Pasca Sarjana Universitas Gunadarma 1

Dasar Teknologi Informasi

Mohammad Iqbal, PhDPertemuan 2


Ada apa di balik “Gadget” Digital

Desktop komputerTablet, laptop, netbook, webbook Smartphone : Blackberry, Iphone, Android based, Windows based, Symbian based.Smart home, smart car

10-Mei-12 @Pasca Sarjana Universitas Gunadarma3

Ada apa di balik Gadget Digital

ProcessorI/O system : Input method, Visual and screen tech, connectivity, Storage System : local, networkNetworking System : WIFI, GSM, LAN 2 WAN, InternetData communicationmethod : VPN, encryption, compressionData Services : text, voice, images, video streaming, teleconferencing & webinar (multimedia) Security


Ada apa di balik Gadget DigitalProcessor

AMD

IntelTabletSmartphone



I/O system : Input method

1. Keyboard Basic2. Non Traditional

Keyboard3. Haptics System


Ada apa di balik Gadget DigitalI/O system : Input method

1. Keyboard Basic2. Non Traditional Keyboard3. Haptics System

Keyboard Typewriter Layout :Dvorak, (places all of the vowels on

the left side and the most common consonants on the right) ABCDE, XPeRT, QWERTZ and AZERTY

Keyboards Keys (80 and 110) :Typing keys A numeric keypad Function keys Control keys

Inside The Keyboards :Controller Key Matrix Key Mechanics

Rubber dome Membrane Metal contact Foam element

Wireless Keyboard



2. Non Traditional Keyboard : ErgonomicProgrammable Hot key

Backlight

The SafeType

Touch Screen Keyboard

Xynergy Keyboard



2. Non Traditional Keyboard : Virtual Keyboard

Collaboration with Augmented Reality



2. Mouse / mice

Wireless Mouse :RF or Bluetooth

track-ball mouse (optomechanical )

Optical mouse Mouse Connector

PS/2 USB

Haptics Screen



4. Haptics System (Touch Technology)

The Omni®, the entry-level device in the PHANTOM line from

SensAble Technologies

Keyboards : allow users to type in words joysticks : steering wheels can vibrateHaptics : User can touch what's inside the virtual world

exoskeleton



4. Haptics System (Touch Technology)



I/O system : Visualization & Screen Tech.Type of ScreenTechnology behind screen

Ada apa di balik Gadget Digital Video Display Resolution

EGA (extended graphics adapter)640 X 350

VGA (video graphics adapter)640 X 480

SVGA (super VGA)800 X 600

SXGA (super extended graphics array1024 X 768

UXGA (ultra-extended graphics array1600 X 1200

cathode ray tube (CRT)phosphors excited by electron gun beamsRGB composite colorhorizontal scanning pattern to refresh phosphors

Ada apa di balik Gadget Digital CRT technology

Ada apa di balik Gadget Digital Flat-Panel Displays

LCD (liquid crystal displays)active matrix (TFT)passive matrix

other technologiesplasma, SED, etc. Plasma


Touch Screen Technology

1. Resistive SystemIn this resistive mechanism of touch screen two sheets are used one is conductive and the other is resistive. Both cover the top glass panel. There is a space between two sheets so that current pass when it is toggle. Now touching the screen forced both layers to contact at a certain point. This contact of both layers cause in the electric field a variation which is informed to the main system that a touch is felt. OS transcribe the touch into desired action.

Three different systems used in the mechanism of touch screen :1. Resistive System2. Capacitive System3. Surface Acoustic Wave System



1. Resistive System



1. Resistive SystemExample :



2. Capacitive SystemTo understand this mechanism, it is better to know about human biology first. Many chemical reactions take place in our body and electricity produced in result to perform different functions. That is the reason why human heart is recharged with electric shocks for the recovery. In this system an electric charge sheet (capacitor) is directly placed on the glass. When we touch the screen with finger, a static charge produces and reacts with the capacitor (electric charge sheet). As the touch screen works due to electric current develop when touches the finger.



2. Capacitive SystemExample : Blackberry



3. Surface Acoustic Wave SystemThis type of touch screen works with the help of wave energy. This enables a touch to transform into another form of energy and deliver the command which in response perform the desired action.A pair of transducers is placed on glass plate sides. In the glass plate there are reflectors. On touching the screen wave produced and which transforms into energy for fulfilling the command. It tells where on the screen touch is detected.


Touch Screen Technology3. Surface Acoustic Wave SystemExample :IPhone


Multi-touch System


Visual Enhanced TechnologyHologramVirtual Reality Augmented reality



I/O system : Connectivity

internal vs. externalParallel vs Serial communicationWire vs wireless (by RF, bluetooth, WIFI, IR)



I/O system : Connectivityinternal vs. externalParallel vs Serial communicationWire vs wireless (by RF, bluetooth, WIFI, IR)

Parallel communicationsIDE (Integrated Drive Electronics)

Hard drives, CD-ROM16-bit parallel

PCI (Peripheral Component Interconnection)

network interface cards, video graphic adapters, etc.32 or 64 bit parallel

Internal Bus Types PCMCIA (Personal Computer Memory Card International Association)

laptop expansion cards16 bits parallelnewer CardBus supports 32 bits

SCSI (Small Computer System Interface)

several generations


RS-232PS/2 mouse and keyboardUSBFirewire

External Serial Bus TypesPS/2

up to 6 Mbps; 2.0 -- 480 Mbps!two types of connectors

“A”-- upstream connections (to computer)“B” -- downstream connections (to device)

USB hub : provides multiple connectionshot-swappable

Universal Serial Bus

Shielded wires for power -- +5 volts (red) and ground (brown) -- and a twisted pair (yellow and blue) of wires to carry the data.

Type A Type B

USB 2.0 (High-speed USB) provides additional bandwidth for multimedia and storage applications and has a data transmission speed 40 times faster than USB 1.1

The USB 3.0 (SuperSpeed USB) standard became official on 2008. USB 3.0 boasts speeds 10 times faster than USB 2.0 at 4.8 gigabits per second.


Specification IEEE 1394 High Performance Serial BusFast transfer of data : Data rates at 100, 200, and 400 Mbps – max cable length4.5 metersNew standard 800 Mbps, max cable length 100 metersSelf-configuring, Plug-and-play performance (hot-swappable)Ability to put lots of devices on the bus Provision of power through the cable Low cabling cost

Firewire (IEEE 1394)


Bluetooth is essentially a networking standard that works at two levels:1. It provides agreement at the

physical level -- Bluetooth is a radio-frequency standard.

2. It provides agreement at the protocol level : how many will be sent at a time, and how the parties in a conversation can be sure that the message received is the same as the message sent.

BluetoothBluetooth networking transmits data via low-power radio waves. It communicates on a frequency of 2.45 gigahertz (actually between 2.402 GHz and 2.480 GHz, to be exact). Can connect up to eight devicessimultaneously. With all of those devices in the same 10-meter (32-foot) radius Service-level security and device-level security work together to protect Bluetooth devices from unauthorized data transmission. Security methods include authorization and identification procedures that limit the use of Bluetooth services to the registered user and require that users make a conscious decision to open a file or accept a data transfer.


WiFi is IEEE standard 802.11 networking. Communication across a wireless network is a lot like two-way radio communication. Here's what happens:

1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.

2. A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.

WIFIWireless adapters Access Point

(Hotspot)

Securing WIFI network methods:WiFi Protected Access (WPA) is a step up from WEP

(Wired Equivalency Privacy ) and is now part of the 802.11i wireless network security protocol. It uses temporal key integrity protocol (TKIP) encryption. As with WEP, WPA security involves signing on with a password. Most public hotspots are either open or use WPA or 128-bit WEP technology, though some still use the vulnerable WEP approach.Media Access Control (MAC) address filtering is a little

different from WEP or WPA. It doesn't use a password to authenticate users -- it uses a computer's physical hardware.



Storage System : local vs network



Storage System : local vs networkBasic types of storage

Direct attached storage (DAS), Storage area network (SAN), Network attached storage (NAS) are the three.

1. DAS is the basic building block in a storage system, and it can be employed directly or indirectly when used inside SAN and NAS systems.

2. NAS is the highest layer of storage and can be built on top of a SAN or DAS storage system.

3. SAN is somewhere between a DAS and a NAS.




SCSI -- Small computer system

interface

1. Direct attached storage (DAS)

PATA -- Parallel advanced technology attachment (ATAPI/IDE)




SATA -- Serial advanced technology attachment is the official successor to PATA.


SAS -- Serial attached SCSI can be seen as a merged SCSI and SATA interface




FC -- Fibre channel is both a direct connect storage interface used on hard drives and a SAN technology.Flash -- Flash memory isn't a storage interface, but it is used for very high-end storage applications because it doesn't have the mechanical latency issues of hard drives.RAM -- Random access memory


Flash

FC




FC -- Fibre channel is high-end forms of a SAN. It's common for FC SANs to use native FC hard drivesiSCSI -- Internet SCSI is a low-cost alternative to FC that's considered easier to manage and connect because it uses the common TCP/IP protocol and common Ethernet switches.AoE -- ATA over Ethernet is the most recent SAN technology to emerge, created as an even lower-cost alternative to iSCSI. AoE is a technology that encapsulates ATA commands into low-level Ethernet frames and avoids using TCP/IP.

2. Storage Area Network (SAN)




NAS is a file-level storage technology built on top of SAN or DAS technology. It's basically another name for "file server." NAS devices are usually just regular servers with stripped down operating systems that are dedicated to file serving. NAS devices typically use SMB (server message block) for Microsoft compatibility or NFS (network file system) for UNIX compatibility.

2. Network attached storage (NAS)




The benefit of a NAS over a SAN or DAS is that multiple clients can share a single volume, whereas SAN or DAS volumes can be mounted by only a single client at a time. The downside to a NAS is that not all applications will support it because they're expecting a block-level storage device, and most clustering solutions are designed to run on a SAN.

2. Network attached storage (NAS)



Networking System :Internet infrastructureMethod to connect :

Dial upDSLWIFIWIMAXSattelliteCellular

Basic Computer Networking


Ada apa di balik Gadget DigitalNetworking System :

Internet InfrastructureComputer using a modem or via LAN

to connect to an Internet Service Provider (ISP). When you connect to your ISP, you become part of their network. The ISP may then connect to a larger network and become part of their network. The Internet is simply a network of networks.Most large communications companies

have their own dedicated backbonesconnecting various regions. In each region, the company has a Point of Presence (POP). Instead, there are several high-level

networks connecting to each other through Network Access Points or NAPs.

Ada apa di balik Gadget DigitalHow the Internet Works

DATAGRAMs are packets of data that also contain addressing informationTCP/IP define protocols (standards) for how datagrams are packaged and deliveredIP address is a number that signifies the address of an Internet hostDomain names are pseudonyms for IP addressesDomain name system servers provide user with IP numbers for URLs, e-mail addresses, etc.

How the Internet Works


Gateways and Routers transmit datagrams across the InternetClient/Server applications add functionality to the Internet


IP (Internet Protocol)how datagrams are routed across the network

TCP and UDPhow messages are deliveredTCP -- guaranteed service (e-mail, HTTP, etc.)UDP -- normal service (PING, DNS, etc.)

Ada apa di balik Gadget DigitalBasic Internet Applications

ELECTRONIC MAIL (EMAIL)asynchronous communications

mail clientmail server


REMOTE LOGINS (TELNET)—synchronous 2-way communications

local hostremote host


FILE TRANSFER PROTOCOL (FTP)—exchanging data and programs between systems

anonymous ftpHTTP (HyperText Transfer Protocol)cookies

ID used for identifying users, transactions, etc.

Web cachingclient-sideserver-side -- proxy servers

Ada apa di balik Gadget DigitalInternet 2

consortium of government , industry, and educationestablish network capabilities to support national researchdevelop the next generation of Internet applicationstransfer these to worldwide Internet

Ada apa di balik Gadget DigitalInternet 2

remote instrumentation and virtual laboratoriesdistance learningdigital librariesTele-immersionmulticasting

Abilene



Networking System : Method to Connect

1. Dial-up Connection : modem via phone line

2. DSL Connectionconnect to the Internet by through a cable modem or through a digital subscriber line (DSL) connection. DSL is a very high-speed connection that uses the same wires as a regular telephone line.



3. WiFi Connection

4. WiMax Connection, also known as 802.16, looks to combine the benefits of broadband and wireless. WiMax will provide high-speed wireless Internet over very long distances and will most likely provide access to large areas such as cities.




4. WiMax Connection


WiMAX base station 10 miles from your home



3. Satellite Connection




4. Cellular Connection (GSM/CDMA): The central antenna is a powerful transmitter --transmit 40 or 50 miles (about 70 km).




4. Cellular Connection (GSM/CDMA):Cell Phone Network Technologies

2G : 1st generation used the mobile with analog system only used for the verbal communication. 2G Technology mobiles are able to do not only verbal communication but also able to send text.3G & 3.5G : 3G technology is intended for the true multimedia cell phone -- typically called smartphones -- and features increased bandwidth and transfer rates to accommodate Web-based applications and phone-based audio and video files.4G : lastest technology (not implemented at all) -- more bandwidth and services .


Radio Mode & Band Technology:GSM/TDMA operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the 850-MHz and 1900-MHz (sometimes referred to as 1.9-GHz) band in the United States. CDMA operates in both the 800-MHz and 1900-MHz frequency bands.Multiple mode & band



4. Cellular Connection Internet using Cellular Technology


WAP is designed to work on any of the existing wireless services, using standards such as:Short Message Service (SMS)High-Speed Circuit-Switched Data (CSD)General Packet Radio Service (GPRS)Unstructured Supplementary Services Data (USSD)


Ada apa di balik Gadget DigitalNetworking System :

Basic Networking SystemNetworking :

Scale : LAN; MAN, WANTipologi : Star, bus, ring, token ring, hybridMedia : bounded (copper wire, optical fiber cable), unbounded media(“wireless”, RF waves)Device : repeater, bridge, hub, switch, router



Data Communication Method :Digital Compression EncryptionVPN (Virtual Private Network)

Ada apa di balik Gadget Digital Digital Compression Concepts

Compression techniques are used to replace a file with another that is smallerDecompression techniques expands the compressed file to recover original data -- exactly or in facsimileA pair of compression/decompression techniques that work together is called a codec for short


Ada apa di balik Gadget Digital Types of Codecs

Codecs that upon decompression always reproduce the original file exactly are called lossless codecsCodecs that reproduce only an approximation of the original file upon decompression are called lossy codecsCodecs that take approximately the same amount of time to compress and decompress a file are referred to as symmetric codecsBy contrast, codecs that feature simple fast decompression but significantly slower compression are called asymmetric codecs


Ada apa di balik Gadget Digital Compression Encoding

Compression is an encoding process that filters the original file in several successive stages


Ada apa di balik Gadget Digital Codec Methods

Syntactic encoding (also called entropy encoding) methods attempt to reduce the redundancy of symbolic patterns in a file without any regard to the type of information representedSemantic methods consider special properties of the type of information represented to reduce nonessential information in a fileHybrid methods combine both syntactic and semantic methods


Ada apa di balik Gadget DigitalCompressing Text and Numerical Data

Run-Length Encoding (RLE)looks for repeated sequences of symbolswidely used for fax (facsimile) transmissions

Huffman Codesexploits frequency distribution of symbols in a sourceadaptive Huffman coding builds its own frequency tables rather than use predefined statistics

Lempel-Ziv-Welch (LZW) compressionbased on recognizing patterns of strings in original filefast and yields good results (50% typical reduction)

Lossless Syntactic Methods


Ada apa di balik Gadget DigitalCompressing Images

GIF (Graphic Interchange Format) Codecemploys LZW method for lossless compression

TIFF (Tagged Image File Format) Codeclossless syntactic method

JPEG (Joint Photographics Experts Group) Codec

umbrella term covering several lossy and lossless methodsbaseline method is most commonly used one -- lossy method based on a hybrid method


Ada apa di balik Gadget DigitalCompressing Video

Video compression employs both spatial and temporal compression

spatial techniques compress individual framestemporal methods compress data in frames over time

QuickTime and AVI (Audio Video Interleaved) are two popular (and incompatible with each other) formats

Some Additional MethodsDVI (Digital Video Interactive)Motion-JPEGMPEG (Motion Pictures Experts Group)The px64 Standard10-Mei-12 @Pasca Sarjana Universitas Gunadarma

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Ada apa di balik Gadget DigitalTemporal Compression in Video

Lossy strategies for eliminating redundancy of information between frames employ temporal compression -- referred to as interframecompressionSequence of frames are considered together

key framesdifference frames

Used in QuickTime and DVI


Ada apa di balik Gadget DigitalTemporal Video Compression (cont’d)

MPEG and related codecs employ a more complex frame-referencing method

intrapictures (I pictures)predicted pictures (P pictures)bidirectional pictures (B pictures)


Ada apa di balik Gadget DigitalCompressing Audio

A widely used method is ADPCM (Adaptive Differential Pulse Code Modulation)ADPCM

lossy methodemploys a differencing technique related to those used in video compressionused in DVI

MP3 employs psychoacoustic methods filter out parts of the signal most people do not hear uses methods to measure the amount of quantization that will just mask noise


Ada apa di balik Gadget DigitalEncryption and Data Security

Cryptography is the art and science of keeping message secretEncryption techniques convert data into a secret code for transmissionThe process of retrieving the original message at the receiver is called decryption


Ada apa di balik Gadget DigitalEncryption Keys

Keys are essential information -- usually a numerical parameter(s) -- needed for encryption and/or decryption algorithmsEncryption keys are used to encode plaintext as encoded ciphertextDecryption keys are used to decode ciphertextand recover the original plaintextDecryption keys are sometimes discovered by brute force methods employing computers to search large potential key spaces


Ada apa di balik Gadget DigitalSymmetric or Secret Key Ciphers

Secret key ciphers use a single secret key (or set of keys) for both encryption and decryptionThe secret key must be transferred securely in order for secret key methods to be secureData Encryption Standard (DES) is a US government sponsored secret key cipher. DES uses a 56-bit key.International Data Encryption Algorithm (IDEA) has been proposed to replace DES. It uses a 128-bit key.Longer keys make it more difficult for brute force discovery of the secret key


Ada apa di balik Gadget DigitalAsymmetric or Public Key Ciphers

The first practical public key algortihm was published by Rivest, Shamir, and Adleman in 1976 and is know as RSA (for their last names)Public key ciphers employ an algortihm with two keys -- a public key and a private keyA sender looks up the recipient's public key and uses it to encode a messageThe recipient then decodes the message with his or her private key (this private key is necessary to decode the message)


Ada apa di balik Gadget DigitalAsymmetric or Public Key Ciphers Illustrated


Ada apa di balik Gadget DigitalMore on Public Key Methods

No attempt is made to keep secret the actual encryption and decryption algorithms for public key methods -- security depends on only the recipient knowing his or her private keyPublic key ciphers are more secure than secret key ciphers, but are not as efficient since they require longer keys and more computing in the encryption and decryption processesFor sake of efficiency, sometimes secret key encryption is used and the secret key is communicated employing public key methods -- the combination of a secret key encoded message and public key encoded value of the secret key is called a digital envelope


Ada apa di balik Gadget DigitalAuthentication

The process used to verify the identity of a respondent is called authenticationAuthentication is very important for electronic commerce and other network transactionsAuthentication exploits the symmetry of public and private keysTo authenticate that a person is who they say they are:

send that person a nonsense message and ask them to encode it with their private key and return it to youwhen the message is returned, if the person is who they claim to be, you should be able to recover your nonsense message using their public key (which presumably you know)


Ada apa di balik Gadget DigitalEncryption and National Security

An escrowed secret key cipher is a secret key cipher in which a trusted third party controls the secret key. DES is an example of such a cipher, and the US government holds the escrowed 56-bit secret keyThe International Trafficking in Arms Regulation (ITAR) prohibits the export of secret key cipher systems with secret keys longer than 40 bits


Ada apa di balik Gadget DigitalEncryption and National Security

A major governments can break ciphers with 40-bit or shorter keys by brute forceLimiting longer secret key ciphers is an attempt to retain the ability to break codes when this is deemed necessary for national securityThe ITAR law has been debated for a number of yearsPublic key ciphers have complicated the debate further -- and it continuesThe basic issue is privacy versus the national security


Ada apa di balik Gadget DigitalVPN (Virtual Private Network)

A VPN's purpose is providing a secure and reliable private connection between computer networks over an existing public network, typically the Internet.

A good VPN can carry data in a secure, private tunnel across the chaos of the public Internet.



A VPN's equipment:Network access server -- As previously described, a NAS is responsible for setting up and maintaining each tunnel in a remote-access VPN.A firewall provides a strong barrier between your private network and the Internet. AAA Server -- The acronym stands for the server's three responsibilities: authentication, authorization and accounting. For each VPN connection, the AAA server confirms who you are (authentication), identifies what you're allowed to access over the connection (authorization) and tracks what you do while you're logged in (accounting).

One widely used standard for AAA servers is Remote Authentication Dial-in User Service (RADIUS). Despite its name, RADIUS isn't just for dial-up users. When a RADIUS server is part of a VPN, it handles authentication for all connections coming through through the VPN's NAS.



Encryption and Security Protocols in a VPN:Internet protocol security protocol (IPSec) or generic routing encapsulation (GRE)In a remote- access VPN, tunneling typically relies on Point-to-point Protocol (PPP) :

L2F (Layer 2 Forwarding) -- Developed by Cisco; uses any authentication scheme supported by PPPPPTP (Point-to-point Tunneling Protocol) -- Supports 40-bit and 128-bit encryption and any authentication scheme supported by PPP


L2TP (Layer 2 Tunneling Protocol) --Combines features of PPTP and L2F and fully supports IPSec; also applicable in site-to-site VPNs


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