Quiz no. 8

1. Define the term, database,and explain how a database interacts with data and information.

     A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels), in a way that supports processes requiring this information (for example, finding a hotel with vacancies). The term "database" refers both to the way its users view it, and to the logical and physical materialization of its data, content, in files, computer memory, and computer data storage. This definition is very general, and is independent of the technology used. However, not every collection of data is a database; the term database implies that the data is managed to some level of quality (measured in terms of accuracy, availability, usability, and resilience) and this in turn often implies the use of a general-purpose Database management system (DBMS). A general-purpose DBMS is typically a complex software system that meets many usage requirements, and the databases that it maintains are often large and complex.
     The term database is correctly applied to the data and data structures, and not to the DBMS which is a software system used to manage the data. The structure of a database is generally too complex to be handled without its DBMS, and any attempt to do otherwise is very likely to result in database corruption. DBMSs are packaged as computer software products: well-known and highly utilized products include the Oracle DBMS, Access and SQL Server from Microsoft, DB2 from IBM and the Open source DBMS MySQL. Each such DBMS product currently supports many thousands of databases all over the world. The stored data in a database is not generally portable across different DBMS, but can inter-operate to some degree (while each DBMS type controls a database of its own database type) using standard like SQL and ODBC. A successful general-purpose DBMS is designed in such a way that it can satisfy as many different applications and application designers as possible. A DBMS also needs to provide effective run-time execution to properly support (e.g., in terms of performance, availability, and security) as many end-users (the database's application users) as needed. Sometimes the combination of a database and its respective DBMS is referred to as a Database system (DBS).

2.Describe file maintenace techniques (adding records,modifying records,deleting records) and validation techniques.

File Maintenance Techniques
 ›File maintenance refers to the procedures that keep data current. File maintenance procedures include adding records to correct inaccurate data or to update old data with new data, and deleting records when they no longer are needed.

Validation Techniques

 ›Validation is the process of comparing data with a set of rules or values to find out if the data is correct. Many programs perform a validity check that analyzes data, either as you enter it or after you enter it, to help ensure that it is correct.

›Types of validity checks include an alphabetic check, a numeric check, a range check, a consistency check, a completeness check, and a check digit.

3.Discuss the terms character,field,record,and file.

Character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language.

Field is an open-source software project initiated by OpenEnded Group, for the creation of their digital artworks. It is an environment for writing code to rapidly and experimentally assemble and explore algorithmic systems. It is visual, it is hybrid, it is code-based. We think that it has something to offer a diverse range of programmers and artists.

Enter your data, and then press TAB to go to the next field.

To Edit a Record :

       You can change the data in one or more fields in a record. For example, if you want to correct the spelling of a customer name, you can open the Customers form in Form view, move to the record that corresponds to the customer, and edit the Name field in the form. When you move to a different  record, Access will automatically update the field in the underlying table.

1. Open the form (in Form view), page (in your Web browser or in Page view), or table (in Datasheet view) that has the record that you want to edit.
2. Move to the record by using the buttons on the navigation toolbar.
3. Use the mouse or the TAB or arrow keys to move to the field that you want to edit.

 To replace the entire contents of a field in a datasheet, click near the left edge of the field when the pointer turns to a plus, as shown in the following example. In a form, click the field's label.

To add to the existing contents of a field, place the insertion point where you want to enter the new characters. You can move the insertion point by using the arrow keys. In the following example, the insertion point is at the end of the current contents of the field, so anything that you type will be appended to the string "Alfreds FutterKiste".

4.Discuss the functions common to most database management systems:data dictionary, file retrieval and maintenance, data security, and backupand recovery.

  Enter your text in the field. If text in the field was selected before you started typing, the characters that you type will replace that text.

Delete a contents of a field or an entire record
You can delete the text in a field to either leave the field blank (if the field supports Null values), or to replace the text with another value. You can also permanently delete one or more records in a table:

• To delete text in a field, select the text and then press DEL.

For information on how to select a field, see Select fields and records.

• To delete one or more records in a datasheet or a form, select the records and then press DEL.
• To delete a record on a data access page, click the Delete button on the record navigation toolbar.

5. Differentiate between a file processing approach and the database approach.

• A database coordinates the physical and logical access to the data; a file-processing system only coordinates physical access to the data
• A DBMS reduces the amount of data duplication
• A DBMS is designed to allow flexibility in what queries give access to the data, where a file-processing system only allows pre-determined access to data (by specific compiled programs)
• A DBMS is designed to coordinate and permit multiple users to access data at the same time. A file processing system is much more restrictive in simultaneous data access.

6. Describe characteristics of relational, object-oriented, andmultidimensional databases.

Relational database-stores data in tables that consists of rows and columns. Each row has a primary key and each column has a unique name.

Object-oriented database (OODB) - stores data in objects;often use an object query language to manipulate and retrieve data.

Multidimensional databas-stores data in dimensions;allows users to access and analyze any view of the database data and no standard query language exists.

 

7.Explain how to access web databases.

 

A Web database links to a form on a Web page. To access data in a Web database, you fill on the form or enter search text on a Web page. A Web database usually resides on a database server, which is a computer that store and provides access to a database.

 

8.Define the term, computer security risks, and briefly describe the typeof cybercrime perpetrators: hacker, cracker, script kiddie, corporate spy,unethical employee, cyberextortionist, and cyberterrorist.

 

Computer security is a branch of computer technology known as Information Security as applied to computers and networks. The objective of computer security includes protection of information and property from theft, corruption, or natural disaster, while allowing the information and property to remain accessible and productive to its intended users. 

 

Cybercrime Perpetrators

Hacker refers to a computer programmer who is able to create usable computer programs where none previously existed. 

Cracker is a variation of hacker , with the analogy equal to a safe cracker. Some individuals use the term cracker in an attempt to differentiate from the honorable computer programmer definition of hacker.

Script kiddy is an individual who executes computer scripts and programs written by others. Their motive is to hack a computer by using someone else’s software. Examples include password decryption programs and automated access utilities. Corporate Spy - have excellent computer and networking skills and are hired to break into a specific computer and steal its proprietary data and information.

Unethical employee - break into their employers' computer for a variety of reasons. Some simply want to exploit security weakness.

Cyberextortionist - is someone who uses e-mail as a vehicle for extortion. These perpetrator s send an organization a threatening e-mail message indicating they will expose confidential information, exploit a security flaw, or launch an attack that will compromise the organization s network - if they are not paid of a sum of money.

Cyber-terrorist - a programmer who breaks into computer systems in order to steal or change or destroy information as a form of cyber-terrorism.

 

9.Identify database design guidelines and discuss the responsibilities of database analysts and administrators.
Database Analysts and Database Administrators are responsible for managing and coordinating all database activities.

Database Analysts (DA) - focuses on the meaning and usage of data. The DA decides on the placement of fields, defines the relationships among data, and identifies user's access privilege.

Database Administrators (DBA) requires a more technical inside view of the data. The DBA creates and maintains the data dictionary, manages data security, monitors database performance, and checks backup and recovery procedures. 

 

10.Discuss techniques to prevent unauthorized computer access and use

Operating system and software patches and updates

There is no such thing as perfect software, often a software program may have several issues and could potentially have security vulnerabilities that can leave your computer open to attacks that compromise your computer and your data.

Software patches, updates, and drivers are made available, often for free, to consumers to help keep a software program and operating systems running properly and secure. If the program you're using does not have any method of checking for updates on its own it is up to you to verify the program is up-to-date. Often this can be done by visiting the web site of the developer who created the program. A listing of third-party companies and links to each of their pages can be found on our third-party support page.

• How to update a Microsoft Windows computer.

Passwords

Make sure a password has been set on computer. Default passwords such as password, root, admin or no password will allow easy access to your computer or your Internet account.

1. Change passwords often. It is recommended at least once every few months.
2. Create a BIOS password.
3. When creating a password, add numbers or other characters to the password to make it more difficult to guess; for example: 1mypassword23!.
4. Do not use sticky notes around your computer to write down passwords. Instead use a password manager.

• Complete information and links to information about computer passwords.

Get a hardware or software firewall

We highly recommend all computer users have a firewall solution. There are two ways a firewall can protect your computer and network.

1. Hardware firewall - A hardware firewall is a hardware device that is connected to your network. Often many home users who have a home network use their network router as a firewall solution.
2. Software firewall - A software firewall is a software program that you install on your computer that helps protect that computer from unauthorized incoming and outgoing data. Below is a listing of a few of the more widely used software firewall programs.

Agnitum Outpost Firewall
BlackICE PC Protection
Kerio Personal Firewall
Sygate Firewall
Tiny software Tiny Personal Firewall
Network Associates
Zone Labs Zone Alarm

Note: A software firewall is only going to protect the computer that has the firewall installed on it.

In addition to the above listed firewall software programs many of the antivirus scanners released today also include their own version of a firewall program. If you have an antivirus scanner that also has a firewall program you do not need to worry about getting one of the above programs or another third-party firewall program.

• How to enable or disable the Microsoft Windows firewall.

Trojans, viruses, spyware, and other malware

Software Trojans, viruses, spyware, and other malware can not only damage or destroy your computer data Internet or even log all your keystrokes to capture sensitive data such as passwords and credit card information. but is also capable of monitoring your computer to learn more about your viewing habits on the

To help protect your computer from these threats we suggest installing a virus protection program as well as a spyware protection program.

• What are the current available antivirus programs?
• My web browser has been hijacked.

Know how to handle e-mails

Today, e-mail is one of the most popular features on the Internet. Being able to identify threats sent through e-mail can help keep your computer and your personal information safe. Below are some of the most common threats you may encounter while using e-mail.

• Attachments - Never open or run e-mail attachments. Viruses, spyware, and other malware are commonly distributed through e-mails that have attachments. For example, an e-mail may want you to open an attachment of a funny video, when it's actually a virus.
• Phishing - Phishing or an e-mail phish is an e-mail that appears to be from an official company (such as your bank) indicating you need to log onto the site to check your account settings. However, the e-mails are actually sites setup to steal confidential information such as your passwords, credit card information, social security information, etc. See the phishing definition for additional information about this term as well as examples of these e-mails.

Alternative browser

Before the release of Microsoft Windows XP SP2 and Internet Explorer 7.0, Microsoft Internet Explorer was notorious for security and spyware related issues. Although it has improved since then we still highly recommend considering an alternative browser such as Mozilla Firefox.

Run system scans to check for vulnerabilities

There are several sites on the Internet that allow users to check their computers for potential threats or issues their network or computer may have that can allow users unauthorized access to their computer. Below are a listing of recommend sites to try: 

Gibson Research Corporation - The Gibson Research Corporation, or GRC, is a great location to learn about network security as well as well as test your computer or network for vulnerabilities. 

 

 

 

 

 

 

 

 

Quiz no. 7

1.Discuss the components required for successful commmunications.


      Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information. Successful communications requires a sending device that initiates a transmission instruction, a communications device that connects the sending device to a communications channel, acommunications channel on which the data travels, a communications device that connects the communications channel to a receiving device, and a receiving device that accepts the 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 communication

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. Many software products provide a means to collaborate, or work online with other users connected to a server. A document management system provides for storage and management of a company’s documents, such as word processing documents, presentations, and spreadsheets. Groupware is software that helps people work on projects or share information over a network. Voice mail allows someone to leave a voice message for one or more people. Web services describe standardized software that enables programmers to create applications that communicate with other remote computers.

4.List of advantages of using a network.

A user can logon to a computer anywhere on the network and access their work files from the file server.

Computers can be managed centrally - with the same software installed on each one.

Time - it is much faster to install an application once on a network - and copy it across the network to every workstation.

Sharing printers, plotters, modems etc saves money and time.

Security - the Network Manager can allocate usernames and passwords to all users to try to prevent unauthorised access.

It is easy and convenient to monitor users - for example websites visited or documents printed - this can be done using software running on the server.

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

Client/server-describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request.

Peer-to-peer (P2P)-computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes.

 

6.Describe the various network communications standards.

 

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.

 

9.Describe commonly used communications devices.

 

Radios are communication systems that send and/or receive electromagnetic waves and consist of a transmitter, receiver, and antenna. Pagers are electronic communications devices that are used to notify or alert a user. Communication received by pagers may be numeric or alphanumeric, depending on the model and complexity of the device.

Other types of communication devices include navigation systems, such as global positioning systems (GPS) instruments and radar systems. GPS communication devices receive satellite communications and use it to provide position information. Radar communication devices use synchronized transmitters and receivers to send radio waves and detect their reflections from objects, surfaces and sub-surface structures.

 

 

 

Quiz 6


1.Define system software and identify the two types of system software.   
 
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it. In other words, software is a conceptual entity which is a set of computer programs, procedures, and associated documentation concerned with the operation of a data processing system. We can also say software refers to one or more computer programs and data held in the storage of the computer for some purposes. In other words software is a set of programs, procedures, algorithms and its documentation. Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. The term was coined to contrast to the old term hardware (meaning physical devices). In contrast to hardware, software is intangible, meaning it "cannot be touched".Software is also sometimes used in a more narrow sense, meaning application software only. Sometimes the term includes data that has not traditionally been associated with computers, such as film, tapes, and records.Examples of computer software include:

• Application software includes end-user applications of computers such as word processors or video games, and ERP software for groups of users.
• Middleware controls and co-ordinates distributed systems.
• Programming languages define the syntax and semantics of computer programs. For example, many mature banking applications were written in the COBOL language, originally invented in 1959. Newer applications are often written in more modern programming languages.
• System software includes operating systems, which govern computing resources. Todaylargeapplications running on remote machines such as Websites are considered to be system software, because the end-user interface is generally through a graphical user interface, such as a web browser.
• Testware is software for testing hardware or a software package.
• Firmware is low-level software often stored on electrically programmable memory devices. Firmware is given its name because it is treated like hardware and run ("executed") by other software programs.
• Shrinkware is the older name given to consumer-purchased software, because it was often sold in retail stores in a shrink-wrapped box.
• Device drivers control parts of computers such as disk drives, printers, CD drives, or computer monitors.
• Programming tools help conduct computing tasks in any category listed above. For programmers, these could be tools for debugging or reverse engineering older legacy systems in order to check source code compatibility.

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. This brand includes the following software:
   .UNIX-(officially trademarked as UNIX, sometimes also written as Unix) is a multitasking, multi-use 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 in C, 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.
   .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, to desktop computers, mainframes and supercomputers. Linux is a leading server operating system, and runs the 10 fastest supercomputers in the world.
   .Solaris-is a Uni 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 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 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 a real-time operating system for a wide range of small-footprint consumer and enterprise devices. Development tools like Platform Builder, a Visual Studio 2005 plug in, provide an integrated development environment (IDE) that enables you to build applications and Windows Embedded CE operating system software in a familiar environment.
    .Windows Mobile- is a mobile operating system developed by Microsof that was used in smartphones and mobile devices,but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone 7, which does not run Windows Mobile software. Unlike operating systems for desktop computers, it is usually not possible to upgrade the operating system on a Microsoft based mobile phone via official and legeal means, even by a later release of the same basic operating system let alone a different one; hardware replacement is the only way for less popular and older devices.
     .Palm OS-(also known as Garnet OS) is a mobile operating system initially developed by Palm Inc., for personal digital assistants (PDAs) in 1996. Palm OS is designed for ease of use with a touchscreen-based graphical user interface. It is provided with a suite of basic applications for personal information management. Later versions of the OS have been extended to support smartphones. Several other licensees have manufactured devices powered by Palm OS.
     .iPhone OS-is Apple's mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple devices such as the iPod touch, iPad and Apple TV. Apple doesn't license iOS for installation on third-party hardware. As of May 31, 2011 (2011 -05-31), Apple's App Store contains more than 500,000 iOS applications,which have collectively been downloaded more than 15 billion times. In the last quarter of 2010, it had a 26% share of the smartphone operating system market in terms of units sold, behind Google's Android and Nokia's Symbian. As of May 2010, it accounted for 59% of mobile web consumption—not including the iPad—in North America.
     .BlackBerry- a line of mobile e-mail and smartphone devices developed and designed by Research In Motion (RIM) since 1999.BlackBerry phones function as a personal digital assistant and portable media player. They are primarily known for their ability to send and receive (push) Internet e-mail wherever mobile network service coverage is present, or through Wi-Fi connectivity. They support a large array of instant messaging features, including BlackBerry Messenger.
     .Google Android-is a software stack for mobile devices that includes an operating system, middleware and key applications. Google Inc.purchased the initial developer of the software, Android Inc., in 2005.Android's mobile operating system is based on the Linux kernel. Google and other members of the Open Handset Alliance collaborated on Android's development and release.. The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android. Android was listed as the best-selling Smartphone platform world-wide in Q4 2010 by Canalys.
     . Embedded Linux-is the use of Linux in embedded computer systems such as mobile phones, personal digital assistants, media players, set-top boxes, and other consumer electronicsdevices, networking equipment, machine control, industrial automation, navigation equipment and medical instruments. According to survey conducted by Venture Development Corporation, Linux was used by 18% of embedded engineers.
     .Symbian OS-is a mobile operating system (OS) and computing platform designed for smartphones and currently maintained by Nokia. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user interface component based on S60 5th Edition. The latest version, Symbian^3, was officially released in Q4 2010, first used in the Nokia N8.
4.Explain the purpose of several utility programs:     
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, view, print, play, rename, move, copy, delete, search/find, and modify attributes, properties and permissions. Files are typically displayed in a hierarchy. Some file managers contain features inspired by web browsers, including forward and back navigational buttons.
     .search utility-is a free search utility that will locate a file or folder by name located on any of your hard drives in less than a second. 
    .image viewer- is a computer program that can display stored graphical image; it can often handle various graphics file formats. Such software usually renders the image according to properties of the display such as color depth, display resolution, and color profile.
     .uninstaller-also 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 cleanup-s 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. There are a number of different file categories that Disk Cleanup targets when performing the initial disk analysis:
     .disk defragmenter-is a utility in Microsoft Windows designed to increase access speed by rearranging files stored on a disk to occupy contiguous storage locations, a technique called defragmentation. Defragmenting a disk minimizes head travel, which reduces the time it takes to read files from and write files to the disk. Beginning with Windows XP, Disk Defragmenter also reduces system startup times.     .backup and restore utilities-refers to making copies of data so that these additional copies may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup (often used like an adjective in compound nouns).
     .screen saver-s a type of computer program initially designed to prevent phosphor burn-in on CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use. Contemporary screensavers are used primarily for entertainment or security.
     .personal firewall-is an application which controls network traffic to and from a computer, permitting or denying communications based on a security policy.