Test Your Knowledge: Multiple Choice Questions

Abstraction

Task 1: Multiple Choice Questions (0-30 marks)
These questions test your knowledge, degree of understanding, and ability to analyze a scenario. Each question has one right or best answer. In addition to determining this answer you are also asked to reflect on your confidence in whether you selected the right or best answer.
The marking scheme for this task is based on the correctness and your degree of confidence. In total, you may get as many as 30 marks, but not fewer than 0.

Question 1: Abstraction
In Computer Science, we use abstraction when we talk about systems to:
1. Focus on the details relevant for the discussion at hand.
2. Include all possible details into the discussion and not miss anything.
3. Focus on the purely technical aspects and disregard non-technical ones.
4. Hide complexity that we do not understand readily.

Question 2: Network Protocols
Network protocols set rules that govern the exchange or transmission of data between devices.
This means, they:
1. Define which data is transmitted between devices.
2. Define which concrete path data takes through a network.
Define how data is represented and how it is packaged for transfer.
4. Define how the layers of the protocol stack relate to each other.

Question 3: Cost
You and a colleague won a startup grant to build a cloud-based application. The project is limited to one year of funding, with a potential later extension. Which of the following options is likely going to have the best balance between cost and minimizing effort for you and your colleague for the first year:
1. Buying a server system, with preinstalled operating system at a price of £1,000 that satisfies all performance and technical requirements.
2. Renting a server in a data center, with preinstalled operating system, at a price of £1,000 for one year, satisfying all performance and technical requirements.
3. Renting on-demand computational and storage capacities from a Platform/Function-as-a-Service provider. Depending on usage, the price is predicted to be in the £1,000 per year range.

Question 4: GDPR
You are maintaining an online store that has components for the store, ordering, billing, and customer relationship management. To be GDPR compliant, which of the following designs is the least worst, i.e., violates the least rights of your customers and provisions of the regulation?
One assumption is that the customers only agreed for data being used for billing purposes. 1. The system consists of a single well integrated application. Customer data is tracked by the software components to enable adaptation to usage patterns. The system allows to inspect and update customer data. It is designed based on events, with an append-only storage system.

Network Protocols

2. The system consists of a single well integrated application. Customer data is tracked by the components to enable automatic adaptation to usage patterns. The customer data is specific to these parts. Whole system backups are stored off-site.

3. The system consists of multiple parts designed in isolation. It offers access to all data about a customer in a single place, and allows to remove the data. Backups are created incrementally, with whole system backups stored off-site.
4. The system consists of multiple parts designed together and allows to inspect and update customer data. The parts do not track customer data. There are no backups. The system is designed based on events, with an append-only storage system.

Question 5: Environmental Impact
The heat produced by data centers is one of their highest cost factors, and the energy used for cooling them one major factor of their environmental impact. Under which conditions is it more environmentally friendly to run a server in a local server room outside of a data center? 

When the server is performing tasks less 25% of the time and is kept cool by environmental airflow of cooling, without using energy.
2. When the server is performing tasks close to 100% of the time and is kept cool by environmental airflow of cooling, without using energy.
3. When the server is cooled without using energy, independent of how much of the time it is performing tasks.
4. When the server is using green energy, independent of how much of the time it is performing tasks.

Question 6: Command Line
The command line:
1. Allows us to use different commands together to solve problems or answer questions.
2. Is only useful to interact with the network.
3. Is always more effective and efficient than a graphical user interface.
4. Is how experts use computers.

Question 7: Type of Cloud Service
You are hired as a technical consultant for a local company that wants to move an existing server application into the cloud to be able to decommission their old server hardware that takes too much time maintaining. The application uses a similar technical design as the Chat337 application. It is built on Node.js, manages its own lifecycle, but otherwise does not have any complex requirements. Which of the following is the best advice to give to the company? Best means here correct and most cost effective, least development effort and long-term management effort.
1. Advice them to choose an Infrastructure-as-a-Service offering, which provides the highest flexibility. The application will not require any changes, because the IaaS can be setup with the same environment as the old server. However the provider will manage the operating system and middleware for them.
2. Advise them to choose a Platform-as-a-Service offering, which supports Node.js. The application will require only minimal configuration, but no major changes and the underlying software stack will be maintained for them.
3. Advise them to choose a Function-as-a-Service offering. While this will require changes to the application, it will always be the most cost-effective option and the provider will manage the whole software stack under the application.

Cost

Question 8: API Gateway
You are working on a function-as-a-service-based application that supports the Gulbenkian’s ticket booking service. You have two functions ready for deployment. The bookTickets function takes JSON as input that describes which tickets to book. The getEventsForDate function simply takes a date to retrieve all the events scheduled for the date. Which is the most suitable configuration for the API gateway?

Question 9: Packet Switching
Students were asked to describe all problems that may occur in packet switching networks. One student answered the following:
In a packet switching network, packets are transmitted one-by-one to the destination. However, in some cases, packets may get lost for example because they have been travelling too long through the network. Packet corruption is prevented by shielding cables from external
influences.
Rate the answer on the following scale:
1. Excellent, no omissions, no mistakes
2. Good understanding, one minor omission, nomistakes
3. Satisfactory understanding, two omissions or mistakes
4. Unsatisfactory, more omissions or mistakes

Question 10: Encapsulation
The Open Systems Interconnection (OSI) Protocol Model designs network layers with encapsulation in mind. This means lower layers encapsulate higher layers. In practice, the Internet Protocol comes with what we called a Service Code for its header elements (DSCP or ToS in IPv4 and Traffic Class in IPv6). Note, “independent” means that we cannot assume to know what a layer does, and what its data is for.
From the following explanations, which is the one that gets all of the details right?
1. Because of the encapsulation, lower layers are independent of higher layers. They only depend on the lower layers. However, if we want the network to be able to consider the payload of a higher layer, for instance, to ensure a level of service quality, we need to use the service code to have that information on the lower level.
2. Because of the encapsulation, higher layers are independent of lower layers. They only depend on the higher layers. If we want the network to be able to consider the payload of a lower layer, for instance, to ensure a level of service quality, we need to use the service code to have that information on the higher level.
3. Because of the encapsulation, higher layers are independent of lower layers. They only depend on the higher layers. The service code is not strictly needed anymore and a result of the Internet Protocol stack not strictly following the OSI ProtocolModel.
4. The encapsulation ensures that lower layers are independent of higher layers and higher layers are independent of lower layers. Thus, if we want the network to be able to consider the payload of an encapsulated layer, for instance, to ensure a level of service quality, we need to use the service code for the network to considerit.