IB Comp Sci topic 3 (old questions)

all topic 3 questions + answers from before 2014

Outline two precautions that a mobile device user can take to prevent their data from being compromised if they lose their mobile device.

Assign a password to the device; So it cannot be accessed by an unauthorized user and do not store sensitive data on the smartphone; So that it is not there to be found if the device is lost

Compare the use of Ethernet with Bluetooth for data communication in smartphones.

Bluetooth is much slower than Ethernet; Ethernet requires a physical connection, Bluetooth does not; Ethernet is more secure than Bluetooth; An Ethernet network requires additional hardware (routers, hubs, etc). Bluetooth does not;

Discuss the advantages of letting a mobile device transmit the user’s location.

Emergency services can locate a distress call; Friends can see where you are and meet you; Advertisements could be tailored for things that are near you.

Discuss the disadvantages of letting a mobile device transmit the user’s location.

Illegal surveillance is possible; Advertisers could profile your physical habits as well as your online; Loss of location information (eg in a tunnel) could create erroneous data in systems.

Outline one way in which this use can harm the health of mobile phone users.

By being too engaging; Causing the user to not pay attention to the real world

By taking up too much of the users’ time; Causing them to exercise or socialize less

Explain two consequences of the change of protocols for 4G phones.

Seamless integration with internet service; Allows more effective communication.

The IP routing/handling hardware and software design is standard; So designs can be re-used thereby reducing unit.

Discuss the positive effects that the widespread ownership of smartphones is having on students

Contact teachers with queries

Research topics

Replace expensive textbooks

Make study schedules

Store PowerPoint presentations

Discuss the negative effects that the widespread ownership of smartphones is having on students

Become a distraction in class

Reliance on smartphones as knowledge source Plagiarism issues

Cheating in exams

State two differences between Wi-Fi and WiMAX

WiMax has much greater range than Wi-Fi, WiMax has a greater bandwidth than Wi-Fi, WiMax is more secure than Wi-Fi

State two differences between Wi-Fi and Bluetooth

Bluetooth has much less range than Wi-Fi, Bluetooth has much less power than Wi-Fi, Bluetooth cannot work through building walls, Wi-Fi can.

Describe the purpose and structure of a data packet

A standard message format used within a network, contains header and data, header identifies sender and recipient.

Compare the transfer of data in a 4G cellular network to that of a wired Internet connection.

4G bandwidth is shared with others users, wired access is dedicated; wired access only available in one place,4G accessible everywhere; wired access more reliable than 4G.

Define the terms *client* and *server* in terms of a computer network

Client: process of desk top computer or terminal that make requests from a server in a network.

Server: computer system (hardware and software) that controls and co-ordinates clients requests to use or access a major function on a network.

State two functions included in a network data community protocol

Control the error checking, control the structure of the bit packets, control the error correction

Explain one advanatge of a star network topology over a bus network topology.

reduces congestion as a network link is not shared, reduces full network failure because if hub to device cable breaks the entire network can continue to function, additional lines can be added without causing disruption to other network devices.

Outline one key task a packet network protocol must be able to achieve.

packets can be shipped via any combination of nodes, hence the protocol must be able to enable the packets to be assembled into the correct order at the receiving end.

State two network topologies.

Star, Bus, Ring

Outline the need for a protocol in data transmission across a network.

To establish standard method, for transferring data between devices.

In relation to computer networks, define the meaning of the term wide area network

WAN; communications network that connects geographically dispersed hosts. These are often used by multi-national companies.

Outline three characteristics of a communications network.

Network is a collection of data communication hardware, Connected in a way to allow users to share resources, Communications media.

Describe how a check sum could ensure data integrity in the transmission of data.

Checksum is computed from data, Groups of bits, are added before transmission and the sum appended to the group, When the data is received the actual sum is compared with the check sum.

A hospital has a large networked computer system. Data in the computer system in confidential. Identify two ways in which the security of the network within the hospital can be ensured.

Each user should have a personal password, Passwords should be regularly changed, Each computer should have access rights depending on its location.

Describe how data could be recovered in case of corruption.

All data files should be backed up, Backing up needs to be performed daily/weekly, In case of corruption the most recent backup of the master file is loaded.

Outline the network administrator can reduce the risk that sensitive patient data is seen by someone other than a doctor.

Each user should have appropriate access rights, Passwords should be encrypted, File systems should be encrypted, Administrator should record who has logged on from which computer and for how long.

Explain two ways of reducing the time required to transmit data in a computer network.

Data could be compressed before sending, which means less data to send; High speed lines, fibre optics, or dedicated lines could be used, which allows faster transmission than traditional lines.

Outline the role of a gateway in a Wide Area Network

A gateway provides the link between systems by providing the appropriate conversions and adding the appropriate data.

Packet switching over the Internet makes use of standard protocols during its operation. Define the term standard protocol.

Rules/procedures governing the transmission of data that allow data to be correctly received.

Outline the main difference between data security and data integrity.

Deals with preventing the data being intercepted by a third party

Outline how packet switching helps to provide better security for the data being sent.

Data is not sent as on unit, but is divided into separate packets that are formatted, addressed and routed, making the complete message difficult to intercept.

Outline how packet switching is less likely to be affected by network failure.

Individual packets can be sent by different routes, so if one route is down, others can be used.

Identify three pieces of information that a data packet must contain.

Senders IP address, Receivers IP address, Paket number, Total # of packets, Data, Parity bit.

A company has set up a nationwide telephone call centre for enquiries. Depending on the phone number of the caller, a mainframe redirects incoming calls to one of the four servers, each of them located at a regional centre, working with their computers. The network developed is hybrid. __Suggest a physical transmission medium for communication.__

Optical cable, general telecom lines.

A company has set up a nationwide telephone call centre for enquiries. Depending on the phone number of the caller, a mainframe redirects incoming calls to one of the four servers, each of them located at a regional centre, working with their computers. The network developed is hybrid. __Suggest a physical transmission for communication between the server and operators computer.__

Twisted pair coaxial cable (also acceptable: Ethernet cable)

A company has set up a nationwide telephone call centre for enquiries. Depending on the phone number of the caller, a mainframe redirects incoming calls to one of the four servers, each of them located at a regional centre, working with their computers. The network developed is hybrid. Explain why switches would be used rather than hubs in this hybrid network.

Because a switch inspects the data packet received, it forwards the packet to the appropriate server only, Hence the performances of the network are better than with a hub that would broadcast.

State two resources that could be shared on a LAN.

Database/data files, Software, Backing storage devices, Output devices/printer

State two possible communication links that could be used to connect the LAN to a WAN.

Fibre optic cable, Digital line/ISDN line, Satellite link

Outline one advantage and disadvantage to protest groups of communication by social networks.

Pervasiveness, Immediacy, Accessibility, Anonymity, Visibility, Multimedia nature of social networks, Information stored on the server.

A LAN in a healthcare centre allows two receptionist and four doctors to share three PC’s and a printer which are connected to server. The LAN has a star topology, and uses cables. __Define the terms server and client.__

Server: A computer and its software that provides services available through the network.

Client: A computer/terminal and its software used to access the services in a network by sending requests to the server.

The doctors can access only the medical records of the patients; the receptionists cannot access the medical records of the patients and deal only with registering new patients and booking appointments. __Describe how the access of the doctors and the receptionists can be restricted to the appropriate parts of the file system.__

Assign different access rights to the files/parts of the file system to different groups of users.

5\. A school network is connected to the Internet. Outline one threat to the security of the school’s data that may arise from the use of the Internet.

Hackers will attempt to gain access rights or viruses could damage important data/hardware.

Outline two implications of a school administrator being able to monitor students’ use of the Internet.

Lack of privacy-Students could be prevented from visiting unsuitable sites.

A fashion designer works from home to create a new clothing range for a company. __Outline 2 advantages of using a graphic tablet to create a design.__

The design can be precisely drawn/inputted by pen then held in a graphics file/stored within memory, Using the pen changes can be easily made and memory contents easily updated.

A fashion designer works from home to create a new clothing range for a company. __Describe a communication system that would allow a fast transmission of data files from the designer to the company.__

Designer’s computer connected to the Internet with a secure link to the company’s server.

A fashion designer works from home to create a new clothing range for a company. __Outline the benefits of data compression in storing and sending the designer’s work to the company.__

When large graphic files are compressed they occupy less memory space on the designer’s and company’s computers, transmission is quicker and cheaper.

A fashion designer works from home to create a new clothing range for a company. __Explain the need for encryption when sending the designer’s work to the company.__

The data files should be encrypted/secured because they may be intercepted/read, then misused by other designers/companies.