Common Technical Interview Questions and Answers Update on October 30, 2021

Exam Question 81

Do I have to create my own server implementation to use communications APIs?

A. Yes. You are expected to call the communications API’s REST interface from your own back end.
B. No. Communications APIs are created so you don’t have to build your own back end at all.
C. It is up to you and the communications API vendor.

Correct Answer:
C. It is up to you and the communications API vendor.
Answer Description:
In many cases, the expectation is to create a back end of your own to store the logic of your application. You will probably need that in any case, especially when you have some business logic other than the call or message that is being invoked.

That said, some communications API vendors offer serverless implementations, usually called functions, enabling you to run some of that logic you need to create on their own machines. This reduces the complexity of the implementation and the latency of the decisions taking place in your application, as they are done closer to the source.

Exam Question 82

What is the least common denominator across communications API vendors?

A. Support for SMS.
B. Support for SMS and voice.
C. Support for SMS, 2FA and voice.
D. There is no least common denominator.

Correct Answer:
D. There is no least common denominator.
Answer Description:
Communications APIs have no specific definition and no least common denominator across the vendors offering them. Some vendors offer solid SMS and voice capabilities. Others focus on pure IP communications. Others only care about video calling or omnichannel messaging.

As time goes by, the definition and span of communications APIs change. In the future, expect it to be harder to decide what falls into the category of communications APIs and which vendors offer such capabilities.

At the end of the day, if it offers the functionality you need for your application’s communications, it should be good enough.

Exam Question 83

Which is true about DAS?

A. It’s a simpler approach to storage that’s connected directly to the host computer.
B. An external hard drive is the most basic DAS system.
C. Larger DAS systems include multiple solid-state drives or HDDs.
D. It’s a practical choice for small businesses that share data locally and use local storage devices.
E. All of the above.

Correct Answer:
E. All of the above.
Answer Description:
DAS is attached to and managed by a single host computer. It’s a basic form of storage that isn’t networked. Solid-state or hard disk drives in the host computer or in an external enclosure are directly connected to storage controllers in the host.

Exam Question 84

Which is true about NAS?

A. It connects storage to the network using a network fabric.
B. It gives block access to data.
C. It provides dedicated file storage with its own file system.
D. It’s preferred for structured data.
E. It uses protocols such as iSCSI or Fibre Channel.

Correct Answer:
C. It provides dedicated file storage with its own file system.
Answer Description:
NAS provides remote file serving and file sharing, using protocols such as NFS and SMB. Users on a network retrieve stored shared data via a standard Ethernet connection. NAS is preferred for unstructured data, such as email, social media content, images and videos.

Exam Question 85

Which is true about SAN?

A. It uses a switch to connect servers to storage.
B. It must use Fibre Channel networking.
C. It’s best for file-based storage.
D. It attaches directly to a host computer.
E. It accesses files using a protocol, such as NFS or SMB.

Correct Answer:
A. It uses a switch to connect servers to storage.
Answer Description:
A SAN is a high-speed, dedicated network that connects servers to shared pools of storage over a network hardware fabric. It usually uses a switch to let multiple servers easily access the storage. A SAN used to require Fibre Channel switches but now supports Ethernet. A SAN is mainly used for block storage.

Exam Question 86

Which is not part of a SAN architecture?

A. Host layer
B. Fabric layer
C. Object layer
D. Switches
E. Storage layer

Correct Answer:
C. Object layer
Answer Description:
A SAN architecture has a host layer consisting of servers, host bus adapters and the software that HBAs use to communicate with the fabric layer. The fabric layer connects the hosts to the storage devices. The switches are part of the SAN network, which also includes data routers, cables and the communications protocol. The storage layer includes the storage arrays and storage processors.

Exam Question 87

A user sees a NAS device like any network-connected device.

A. True
B. False

Correct Answer:
A. True
Answer Description:
Because it’s attached to a network via a standard Ethernet connection, a NAS system or device appears to users like any network-connected device. The user accesses files by connecting to the NAS, which has an OS that manages data writes and reads.

Exam Question 88

A SAN also appears to users like a network-connected device.

A. True
B. False

Correct Answer:
B. False
Answer Description:
A SAN gets mounted on a user’s computer, where it appears and functions like any local drive. Unlike a NAS system, the OS on the user’s computer handles the reading and writing of data.

Exam Question 89

Which of the following is true when it comes to NAS, SAN and DAS performance?

A. DAS has no performance advantage over NAS or SAN.
B. NAS outperforms SAN, especially for larger numbers of users.
C. For enterprise storage, SAN has the performance edge over NAS.
D. Performance for all three storage types varies with the type of data used and the number of users.

Correct Answer:
C. For enterprise storage, SAN has the performance edge over NAS.
Answer Description:
DAS can outperform networked storage because the server doesn’t cross the network to read and write data. But DAS has limitations: Its storage resources are dedicated to one host, and it can’t be managed via a network. Because they use file systems, NAS systems have lower throughput and higher latency than SAN, although flash use can speed up a NAS. As an independent storage network, SAN can meet the demands of high-performance enterprise applications.

Exam Question 90

Which is true about the costs of the SAN, NAS and DAS?

A. DAS can be the most inexpensive approach to storage.
B. SAN is likely to be the most expensive type of storage.
C. NAS is likely to be more expensive than DAS but less expensive than NAS.
D. All of the above.

Correct Answer:
D. All of the above.
Answer Description:
When it comes to raw storage, DAS is less expensive than SAN or NAS. NAS provides higher capacity storage at a lower cost than SAN. A SAN is built with expensive hardware and tends to be more complex, requiring more skill and knowledge than the other two storage types.