Quiz 7 Communications and Networks

1. Discuss the components required for successful communications.

 Sending device — initiates instruction to transmit data, instructions, or information

Communications device — connects the sending device to the communications channel

Communications channel — media on which data, instructions, or information travel

Communications device — connects the communications channel to the receiving device

Receiving device — accepts transmission of data, instructions, or information

2. Identify various sending and receiving devices.

A sending device initiates the transmission of data, instructions, and information while a receiving device accepts the items transmitted. All types of computers and mobile devices serve as sending and receiving devices in a communications system. This includes mainframe computers, servers, desktop computers, notebook computers, Tablet PCs, smart phones, portable media players, and GPS receivers.

3. Describe uses of computer communications.

Communications technologies include the Internet, Web, e-mail, instant messaging, chat rooms, newsgroups, blogs, wikis, RSS, VoIP, FTP, Web folders, video conferencing, and fax machine or computer fax/modem. Users can send and receive wireless messages to and from smart phones, cell phones, handheld game consoles, and other personal mobile devices using text messaging, wireless instant messaging, picture messaging and video messaging. A wireless Internet access point lets people connect wirelessly to the Internet through a wireless Internet access point. A hot spot is a wireless network that provides Internet connections to mobile computers and devices. A cybercafé is a coffeehouse, restaurant, or other location that provides computers with Internet access. A global positioning system (GPS) analyzes signals sent by satellites to determine an earth-based receiver’s geographic location.

4. List advantages of using a network

>Speed

>Cost

>Security

>Centralized Software Management

>Resource Sharing

>Email

>Work group computing

5. Differentiate among client/server, peer-to-peer, and P2P networks.

 Client server

>One or more computers act as server (host) and other computers, or clients, access server 

  Peer-to-peer
>Simple network that connects fewer than 10 computers 

>Each computer, or peer, has equal capabilities 

P2P networks

>Sometimes called a file sharing network
>Enables users to connect to each other's hard disks and exchange files directly
 

 6. Describe the various network communications standards.

 Network standards defines:

•  Way devices access the medium
•  Speed on different types of networks
•  Types of network technology (cable / wireless)

Protocols

•  Rules on how devices communicate with each other
•  Data format used
•  Coding Scheme
•  Error Handling
•  Sequencing techniques etc.
•  Hardware / Software Vendors try to meet these guidelines

- ANSI, IEEE

- Standardizing Organization

7. Explain the purpose of communications software.

Communication software is used to provide remote access to systems and is also    used to exchange messages in text, audio and video format for the purpose of communication. This software sends and receives data over telephone lines through modems. The communication software allows computers in different geographical regions to communicate with each other through terminal emulators, file transfer programs, chat and instant messaging programs.

8. Describe various types of lines for communications over the telephone network.

• PSTN - Worldwide telephone system that handles voice-oriented telephone calls.
• Dial-up line - Temporary connection using telephone line for communications.
• Dedicated line - Always on connection between two communication devices.  

9. Describe commonly used communications devices.

Dial-up modem

• A dial-up modem converts digital signals to analog signals and vice versa
• Usually in the form of an adapter card

DSL Modem / ISDN Modem-Cable Modem

• Send and receive digital data from DSL(Digital Subscriber Line) / ISDN

Cable Modem 

>Sends and receives data over cable television (CATV) network

>Much faster than dial-up modem or ISDN   

>Sometimes called a broadband modem

Wireless Modem  

>Allows access to the Web wireless from a notebook computer, a smart phone, or other mobile device. 

Hub or Switch  
>Device that provides central point for cables in network. 

Router 
>Connects computers and transmits data to correct destination on network. 

10. Discuss different ways to set up a home network.


11. Identify various physical and wireless transmission media.
   Physical transmission media     
>Twisted-pair cable is used for telephone systems and network cabling*Separately insulated wires are twisted together in a pair*Twisting reduce the noise (disturbances)

>Coaxial cable is often used for cable television wiring 
*Single Copper wire in center
*Woven or braided metal

Quiz 6 - Operating Systems and Utility Programs

1.Define system software and identify the two types of system software.

System software is computer software designed to operate the computer hardware and to provide a platform for running application software.

Two Types of Software System 
An operating system (OS) is a set of programs containing instructions that work together to coordinate all the activities among computer hardware resources.A utility program is a type of system software that allows a user to perform maintenance-type tasks

 2.Briefly describe various server operating systems: Windows Server, UNIX,Linux, Solaris, and NetWare.

Windows Server is a brand name for a group of server operating systems released by Microsoft Corporation. All are part of Microsoft Servers. 

Unix (officially trademarked as UNIX, sometimes also written as Unix) is a multitasking, multi-user computer operating system. The Unix operating system was first developed in assembly language, but by 1973 had been almost entirely recoded in C, greatly facilitating its further development and porting to other hardware.    

Linux can be installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers, routers and video game consoles, to desktop computers, mainframes and supercomputers. Linux is a leading server operating system, and runs the 10 fastest supercomputers in the world. Typically Linux is packaged in a format known as a Linux distribution for desktop and server use. 
 
Solaris is a Unix operating system originally developed by Sun Microsystems. It superseded their earlier SunOS in 1993. Oracle Solaris, as it is now known, has been owned by Oracle Corporation since Oracle's acquisition of Sun in January 2010. Solaris is known for its scalability, especially on SPARC systems, and for originating many innovative features such as DTrace, ZFS and Time Slider. Solaris is registered as compliant with the Single Unix Specification.

NetWare is a network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, with network protocols based on the archetypal Xerox Network Systems stack.

 3.Summarize the features of several embedded operating systems: Windows Embedded CE, Windows Mobile, Palm OS, iPhone OS, BlackBerry, Google Android, Embedded Linux, and Symbian OS.

Windows Embedded CE is optimized for devices that have minimal storage—a Windows CE kernel may run in under a megabyte of memory. Devices are often configured without disk storage, and may be configured as a “closed” system that does not allow for end-user extension (for instance, it can be burned into ROM). Windows CE conforms to the definition of a real-time operating system, with a deterministic interrupt latency. From version 3 and onward, the system supports 256 priority levels and uses priority inheritance for dealing with priority inversion. The fundamental unit of execution is the thread. This helps to simplify the interface and improve execution time.

Windows Mobile for Pocket PC have these standard features:

• Today screen shows the current date, owner information, upcoming appointments, e-mail messages, and tasks. (Home screen in later WM6.5 builds)
• The taskbar shows the current time and the audio volume.
• Office Mobile, a suite of Mobile versions of Microsoft Office applications, including Outlook Mobile.
• Internet Explorer Mobile, an Internet browser developed by Microsoft for Pocket PC and Handheld PC that comes loaded by default with Windows Mobile and Windows CE for Handheld PC.
• Windows Media Player for Windows Mobile.
• Client for PPTP VPNs.
• Internet Connection Sharing (ICS), which in mobile phones allows the phone to make its Internet connection available to computers via USB and Bluetooth.
• File system similar to that of Windows 9x/Windows NT, with support for many of the same file types.
• Ability to multitask.

Palm OS Garnet has the following features:

• Simple, single-tasking environment to allow launching of full screen applications with a basic, common GUI set
• Monochrome or color screens with resolutions up to 480x320 pixel
• Handwriting recognition input system called Graffiti 2
• HotSync technology for data synchronization with desktop computers
• Sound playback and record capabilities
• Simple security model: Device can be locked by password, arbitrary application records can be made private
• TCP/IP network access
• Serial port/USB, infrared, Bluetooth and Wi-Fi connections
• Expansion memory card support
• Defined standard data format for personal information management applications to store calendar, address, task and note entries, accessible by third-party applications.

iPhone OS features the following:
Home screen
The home screen (rendered by "SpringBoard") displays application icons and a dock at the bottom of the screen where users can pin their most frequently used apps. The home screen appears whenever the user switches on the device or presses the "Home" button (a physical button on the device). The screen has a status bar across the top to display data, such as time, battery level, and signal strength. The rest of the screen is devoted to the current application.
Folders
With iOS 4 came the introduction of a simple foldering system. When applications are in "wiggle mode", any two can be dragged on top of each other to create a folder, and from then on, any other 10 "apps" can be added to the folder using the same procedure (maximum folders can handle is 12 on iPhone and iPod touch and 20 on iPad). A title for the folder is automatically selected by the type of applications inside, but the name can also be edited by the user.

Notifications screen 

In the iOS 5 update, the notifications feature has been revamped. Notifications now collate in a window which can be dragged down from the top of the screen (in a similar fashion to the Android OS).

Included applications

The iOS home screen contains these default "apps". Some of these applications are hidden by default and accessed by the user through the Settings app or another method—for instance, Nike+iPod is activated through the Settings app. All of the utilities, such as voice memos, clock, calculator, and compass are in one folder called "Utilities" in 4.0. Many of the included applications are designed to share data (e.g., a phone number can be selected from an email and saved as a contact or dialed for a phone call).
The iPod touch retains the same applications that are present by default on the iPhone, with the exception of the Phone, Messages, Compass and Camera (prior to the 4th generation) apps. The "iPod" App present on the iPhone is split into two apps on the iPod Touch: Music, and Videos. The bottom row of applications is also used to delineate the iPod touch's main purposes: Music, Videos, Safari, and App Store (Dock Layout was changed in 3.1 Update). For the 4th Generation iPod touch, it includes FaceTime and Camera, and the dock layout had changed to Music, Mail, Safari, Video. As of iOS 5.0 (to be released to the public in fall 2011), "iMessage" will be available on all iOS devices running iOS 5.
 
Multitasking
Before iOS 4, multitasking was limited to a selection of the applications Apple included on the devices. Apple worried that running multiple third-party applications simultaneously would drain batteries too quickly. Starting with iOS 4, on 3rd-generation and newer iOS devices, multitasking is supported through seven background APIs:

1. Background audio
2. Voice over IP
3. Background location
4. Push notifications
5. Local notifications
6. Task finishing
7. Fast app switching

Switching applications 

Double-pressing the home button activates the application switcher. A scrollable dock-like interface appears from the bottom, moving the contents of the screen up. Choosing an icon switches to an application. To the far left are icons which function as music controls, and a rotation lock. Holding the icons briefly makes them wiggle (similarly to the homescreen) and allows the user to quit the applications.

Game Center 

Game Center is an online multiplayer "social gaming network" released by Apple. It allows users to "invite friends to play a game, start a multiplayer game through matchmaking, track their achievements, and compare their high scores on a leader board."

BlackBerry OS is a proprietary mobile operating system, developed by Research In Motion for its BlackBerry line of smartphone handheld devices. The operating system provides multitasking and supports specialized input devices that have been adopted by RIM for use in its handhelds, particularly the trackwheel, trackball, and most recently, the trackpad and touchscreen. The BlackBerry platform is perhaps best known for its native support for corporate email, through MIDP 1.0 and, more recently, a subset of MIDP 2.0, which allows complete wireless activation and synchronization with Microsoft Exchange, Lotus Domino, or Novell GroupWise email, calendar, tasks, notes, and contacts, when used with BlackBerry Enterprise Server. The operating system also supports WAP 1.2. Updates to the operating system may be automatically available from wireless carriers that support the BlackBerry over the air software loading (OTASL) service.

Google Android features the following:

Handset layouts	The platform is adaptable to larger, VGA, 2D graphics library, 3D graphics library based on OpenGL ES 2.0 specifications, and traditional smartphone layouts.
Storage	SQLite, a lightweight relational database, is used for data storage purposes
Connectivity	Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi (no connections through Proxy server and no Ad hoc wireless network), LTE, NFC and WiMAX.
Messaging	SMS and MMS are available forms of messaging, including threaded text messaging and now Android Cloud To Device Messaging Framework(C2DM) is also a part of Android Push Messaging service.
Multiple language support	Android supports multiple human languages. The number of languages more than doubled for the platform 2.3 Gingerbread. Android lacks font rendering of several languages even after official announcements of added support (e.g. Hindi).
Web browser	The web browser available in Android is based on the open-source WebKit layout engine, coupled with Chrome's V8 JavaScript engine. The browser scores a 93/100 on the Acid3 Test.
Java support	While most Android applications are written in Java, there is no Java Virtual Machine in the platform and Java byte code is not executed. Java classes are compiled into Dalvik executables and run on Dalvik, a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. J2ME support can be provided via third-party applications.
Media support	Android supports the following audio/video/still media formats: WebM, H.263, H.264 (in 3GP or MP4 container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP container), MP3, MIDI, Ogg Vorbis, FLAC, WAV, JPEG, PNG, GIF (though earlier versions do not support animated GIFs), BMP.
Streaming media support	RTP/RTSP streaming (3GPP PSS, ISMA), HTML progressive download (HTML5 <video> tag). Adobe Flash Streaming (RTMP) and HTTP Dynamic Streaming are supported by the Flash plugin. Apple HTTP Live Streaming is supported by RealPlayer for Mobile, and by the operating system in Android 3.0 (Honeycomb). Microsoft Smooth Streaming is planned to be supported through the awaited port of Silverlight plugin to Android.
Additional hardware support	Android can use video/still cameras, touchscreens, GPS, accelerometers, gyroscopes, magnetometers, dedicated gaming controls, proximity and pressure sensors, thermometers, accelerated 2D bit blits (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics.
Multi-touch	Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology at the time). Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.
Bluetooth	Supports A2DP, AVRCP, sending files (OPP), accessing the phone book (PBAP), voice dialing and sending contacts between phones. Keyboard, mouse and joystick (HID) support is available through manufacturer customizations and third-party applications. Full HID support is planned for Android 3.0 (Honeycomb).
Video calling	Android does not support native video calling, but some handsets have a customized version of the operating system that supports it, either via the UMTS network (like the Samsung Galaxy S) or over IP. Video calling through Google Talk is available in Android 2.3.4 and later.
Multitasking	Multitasking of applications is available.
Voice based features	Google search through voice has been available since initial release. Voice actions for calling, texting, navigation, etc. are supported on Android 2.2 onwards.
Tethering	Android supports tethering, which allows a phone to be used as a wireless/wired hotspot. Before Android 2.2 this was supported by third-party applications or manufacturer customizations.
Screen capture	Android does not support screenshot capture as of 2011. This is supported by manufacturer and third-party customizations.

Quiz 5

1. Differentiate between storage devices and storage media.

 

A data storage device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy, spanning from manual muscle power in handwriting, to acoustic vibrations in phonographic recording, to electromagnetic energy modulating magnetic tape and optical discs.

A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store or retrieve information.

While, a storage medium is any technology (including devices and materials) used to place, keep, and retrieve data. A medium is an element used in communicating a message; on a storage medium, the "messages" - in the form of data - are suspended for use when needed. The plural form of this term is storage media. Although the term storage includes both primary storage (memory), a storage medium usually means a place to hold secondary storage such as that on a hard disk or tape.

2. Identify the uses of tape, magnetic stripe cards, smart cards, microfilm and microfiche, and enterprise storage.

     Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost. A tape drive reads and writes data and information on tape. Business users utilize tape most often for long-term storage and backup. A magnetic stripe card is a credit card, entertainment card, bank card, or other similar card with a stripe that contains information identifying you and the card. A magnetic stripe card reader reads the information stored on the stripe. A smart card, which is similar in size to a credit or ATM card, stores data on a thin microprocessor embedded in the card. A smart card reader reads the information on the smart card and updates it if necessary. Microfilm is a 100- to 215-foot roll of film. Microfiche is a small sheet of film, usually about 4 X 6 inches. Microfilm and microfiche reduce the amount of paper firms must handle, are inexpensive, and have the longest life of any storage media. Enterprises use computers, servers, and networks to manage and store huge volumes of data and information. In an enterprise, some storage systems can provide more than 185 TB of storage, and optical disc servers hold hundreds of optical discs.

3. Describe the various types of flash memory storage: solid state drives, memory cards, USB flash drives, and ExpressCard modules.

A solid-state drive (SSD) is a data storage device that uses solid-state memory to store persistent data with the intention of providing access in the same manner of a traditional block i/o hard disk drive. SSDs are distinguished from traditional hard disk drives (HDDs), which are electromechanical devices containing spinning disks and movable read/write heads.

A memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles. They are small, re-recordable, and able to retain data without power.

            A USB flash drive consists of a flash memory data storage device integrated with a USB (Universal Serial Bus) interface. USB flash drives are typically removable and rewritable, and physically much smaller than a floppy disk.

            ExpressCard is an interface to allow peripheral devices to be connected to a computer, usually a laptop computer. Formerly called NEWCARD, the ExpressCard standard specifies the design of slots built into the computer and of cards which can be inserted into ExpressCard slots. The cards contain electronic circuitry and connectors to which external devices can be connected. The ExpressCard standard replaces the PC Card (also known as PCMCIA) standards.

4. Differentiate among various types of optical discs: CDs, archive discs and Picture CDs, DVDs, and Blu-ray Discs.

The Compact Disc (also known as a CD) is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage (CD-ROM), write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Discs (VCD), Super Video Compact Discs (SVCD), PhotoCD, PictureCD, CD-i, and Enhanced CD. Audio CDs and audio CD players have been commercially available since October 1982.

Picture CD is a product by Kodak, following on from the earlier Photo CD product. It holds photos from a single roll of color film, stored at 1024×1536 resolution using JPEG compression. The product is aimed at consumers. Software to view and perform simple edits to images is included on the CD.

DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than compact discs while having the same dimensions.

Blu-ray Disc (official abbreviation BD) is an optical disc storage medium designed to supersede the DVD format. The disc diameter is 120 mm and disc thickness 1.2 mm plastic optical disc, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB (23.31 GiB) per layer, with dual layer discs (50 GB), the norm for feature-length video discs. Triple layer discs (100 GB) and quadruple layers (128 GB) are available for BD-XL Blu-ray re-writer drives. Currently movie production companies have not utilized the triple or quadruple layer discs, most consumers owned Blu-ray players will not be able to read the additional layers, while newer Blu-ray players may require a firmware update to play the triple and quadruple sized discs.

5. Summarize the characteristics of ink-jet printers, photo printers, laser printers, multifunction peripherals, thermal printers, mobile printers, label and postage printers, and plotters and large-format printers

An inkjet printer is a type of computer printer that creates a digital image by propelling droplets of ink onto paper. Inkjet printers are the most commonly used type of printer and range from small inexpensive consumer models to very large professional machines that can cost up to thousands of dollars.

A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.

An MFP (Multi Function Product/ Printer/ Peripheral), multifunctional, all-in-one (AIO), or Multifunction Device (MFD), is an office machine which incorporates the functionality of multiple devices in one, so as to have a smaller footprint in a home or small business setting (the SOHO market segment), or to provide centralized document management/distribution/production in a large-office setting.

A thermal printer (or direct thermal printer) produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. The coating turns black in the areas where it is heated, producing an image. Two-color direct thermal printers can print both black and an additional color (often red) by applying heat at two different temperatures.