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Monday, July 25, 2011

Quiz 7

Quiz 7 Communications and Networks

1. Discuss the components required for successful communications.
answer:

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.
answer: 
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.
answer:
Computers can be instructed to perform a variety of individual functions. A set of instructions that tells a computer what to do is called a program. Today, more than 10,000 application programs are available for use on personal computers. They include such popular programs as word processing programs, spreadsheet programs, database programs, and communication programs.
Word processing programs are used to type, correct, rearrange, or delete text in letters, memos, reports, and school assignments. Spreadsheet programs enable individuals to prepare tables easily. The users of such programs establish rules for handling large groups of numbers. For example, using a spreadsheet program, a person can enter some numbers into a table and the program will calculate and fill in the rest of the table.
Spreadsheets may be used for preparing budgets and financial plans, balancing a cheque book, or keeping track of personal investments.
Database programs allow a computer to store large amounts of data (information) in a systematic way. Such data might include the name, address, telephone number, salary, and starting date of every employee in a company. The computer could then be asked to produce a list of all employees who receive a certain salary.  
Communication programs connect a personal computer to other computers. People can thereby exchange information with one another via their personal computers. In addition, communication programs enable people to link their personal computers with databanks. Databanks are huge collections of information stored in large centralized computers. News, financial and travel information, and other data of interest to many users can be obtained from a databank.

4. List advantages of using a network.
answer:
  • share software
  • share information with others on networks
  • share peripherals
  • speed of sharing software and information files
  • cheaper than buying individual software and hardware for each standalone especially if for a school, network software often offers deals for amount being purchased
  • security, files can be copy inhibit mode
  • centralized software management- software being loaded onto one computer but also this loads software to entire network at one time
  • electronic mail(e-mail) between network users, ideal for office memos
  • flexible access- access you files from any computer on the network unlike standalone which would mean only being able to access your data from the one computer you uploaded data onto.
5. Differentiate among client/server, peer-to-peer, and P2P networks.
answer:  
client - server model => One or more computers act as server and other computers or clients access server.

The client–server model of computing is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. A server machine is a host that is running one or more server programs which share their resources with clients. A client does not share any of its resources, but requests a server's content or service function. 

peer - to - peer (P2P) => Simple network that connects fewer than 10 computers.Each computer, or peer, has equal capabilities.
Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers.Peers make a portion of their resources, such as processing power, disk storage or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers of resources, in contrast to the traditional client–server model where only servers supply (send), and clients consume (receive).


6. Describe the various network communications standards.
answer:
Network communication standards are certain rules and specifications framed by standard organisations for manufacturing network hardware and developing network software.

7. Explain the purpose of communications software.
answer:
The purpose of 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.

  • Programs that help users establish connection to Internet, other network, or another computer.
  • Programs that help users manage transmission of data, instruction, and information.
  • Programs that provide an interface for users to communicate with one another.


8. Describe various types of lines for communications over the telephone network.
answer: 
A telephone network is a telecommunications network used for telephone calls between two or more parties.
There are a number of different types of telephone network:
  • A fixed line network where the telephones must be directly wired into a single telephone exchange. This is known as the public switched telephone network or PSTN.
  • A wireless network where the telephones are mobile and can move around anywhere within the coverage area.
  • A private network where a closed group of telephones are connected primarily to each other and use a gateway to reach the outside world. This is usually used inside companies and call centres and is called a private branch exchange (PBX).
9. Describe commonly used communications devices.
answer:
  • 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 wirelessly 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.
answer: 
 A home network can be enabled in a Windows XP system through various ways.In wired connections, the user can enable the home network option through the use of various physical media. The computers should be connected through wires with the help of a router. A wireless connection can be established without any physical medium and thus the user can stay at any position within the wireless range. For wireless connections, wireless-enabled devices are required to connect the system to the network. Configuring a Virtual Private Network is another method that is used to set up or access a home network. Home network connections can also be enabled through local area connections.
11. Identify various physical and wireless transmission media.
answer:



Physical Wireless transmission media  =>  Wire, cable and other tangible materials used to send communication signals.Used when inconvenient, impractical or impossible to install cables. It includes Bluetooth and IrDA.

Quiz 6

Quiz #6

1. Define system software and identify the two types of system software.
 System software refers to the files and programs that make up your computer's operating system. System files include libraries of functions, system services, drivers for printers and other hardware, system preferences, and other configuration files. The programs that are part of the system software include assemblers, compilers, file management tools, system utilities, and debuggersThe system software is installed on your computer when you install your operating system. You can update the software by running programs such as "Windows Update" for Windows or "Software Update" for Mac OS X. 
       2 Types Of System Software
  • Operating System
  • Utility Program
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
- Unix  is amultitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie,Brian Kernighan, Douglas McIlroy, and Joe Ossanna. The Unix operating system was first developed in assembly language, but by 1973 had been almost entirely recoded inC, greatly facilitating its further development and porting to other hardware. Today's Unix systems are split into various branches, developed over time by AT&T as well as various commercial vendors and non-profit organizations. The second edition of Unix was released on December 6th, 1972.
- Linux refers to the family of Unix-like computer operating systems using the Linux kernel. Linux can be installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers, routers and video game consoles, todesktop computers, mainframes and supercomputers. Linux is a leading serveroperating system, and runs the 10 fastest supercomputers in the world. The development of Linux is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed, both commercially and non-commercially, by anyone under licenses such as the GNU General Public License. Typically Linux is packaged in a format known as a Linux distribution for desktop and server use. Some popular mainstream Linux distributions include Debian (and its derivatives such as Ubuntu),Fedora and openSUSE. Linux distributions include the Linux kernel, supportingutilities and libraries and usually a large amount of application software to fulfill the distribution's intended 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.[3][4] Solaris supports SPARC-based and x86-based workstations and servers from Sun and other vendors, with efforts underway to port to additional platforms. Solaris is registered as compliant with the Single Unix Specification.
- NetWare is a network operating system developed by Novell, Inc. It initially usedcooperative 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.
Microsoft Windows CE  is an operating system developed by Microsoft for embedded systems. Windows CE is a distinct operating system andkernel, rather than a trimmed-down version of desktop Windows. Windows 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.
- Features Windows Mobile
Palm OS  is designed for ease of use with a touchscreen-based graphical user interface.
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/USBinfraredBluetooth 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:
  • Multitasking
  • Fast App Switching
  • Local Notification
  • App Folders
  • New App E-mail
  • iBooks
- Blackberry Features:

  • Multi-touch Interface
  • Webkit Browser
  • Home Screen
  • Universal Search
  • Context Sensitive Menus
  • Social Tools
Google Android Features:
  • Handset layouts
  • Storage
  • Connectivity
  • Messaging
  • Multiple language support
  • Web browser
  • Java support
  • Media support
  • Streaming media support
  • Additional hardware support
  • Multi-touch
  • Bluetooth
  • Video calling
  • Multitasking
  • Tethering
  • Screen Capture
4. Explain the purpose of several utility programs: file manager, search utility, image viewer, uninstaller, disk cleanup, disk defragmenter, backup and restore utilities, screen saver,
 personal firewall, antivirus programs, spyware and adware removers, Internet filters, file compression, media player, disc burning, and personal computer maintenance.
  • File Manager - is a computer program that provides a user interface to work with file systems. The most common operations performed on files or groups of files are: create, open, edit, viewprintplay, rename, move, copydelete, search/find, and modify attributes, properties and permissions.
  • Image Vieweris a computer program that can display stored graphical image; it can often handle various graphics file formats.
  • Uninstalleralso called a deinstaller, is a utility software designed to remove other software or parts of it from a computer. It is the opposite of an installer.
  • Disk cleanupis a computer maintenance utility included in Microsoft Windows designed to free up disk space on a computer's hard drive. The utility first searches and analyzes the hard drive for files that are no longer of any use, and then removes the unnecessary files. 
  • Disk defragmenteris a process that reduces the amount of fragmentation in file systems. It does this by physically organizing the contents of the mass storage device to store files in a contiguous region if possible, or in the smallest possible number of regions (fragments) if not. It also attempts to create larger regions of free space using compaction to impede the return of fragmentation. Some defragmenters also try to keep smaller files within a single directory together, as they are often accessed in sequence.
  • Backup Utility - allows users to copy files to another storage medium.
  • Restore Utility - reverses the process and returns backed up files to their original form
  • Screen Saver - causes a display device’s screen to show a moving image or blank screen if no activity occurs for a specified time
  • Personal Firewall - detects and protects a personal computer from unauthorized intrusions
  • Anti Virus Program - protects a computer against viruses
  • Spyware removers - detects and deletes spyware and other similar programs
  • Adware remover-  is a program that detects and deletes adware
  • Internet Filtersare programs that remove or block certain items from being displayed
  • File Compression - shrinks the size of a file(s), compressing files frees up room on the storage media.
  • Media Playerallows you to view images and animation, listen to audio, and watch video files on your computer
  • Disc Burning - writes text, graphics, audio, and video files on a recordable or rewritable optical disc.
  • Personal Computer Maintenance - identifies and fixes operating system problems, detects and repairs disk problems, and includes the capability of improving a computer’s performance