Question

1. Select the characteristics of software quality in use from below.

   		Performance efficiency
   		Freedom from Risk
   		Effectiveness
   		Satisfaction
   		Functional suitability
   		Efficiency
   		Security
   		Maintainability

3- List two main problems that are important for almost all of the software architecture principles.

5- What is the difference between external and internal product quality?

6- What types of software architecture patterns will you choose if your system requires multiple expertise and needs to be used in a distributed environment? Justify your choice

Answer 1

From the given options the characteristics of software quality in use are:

Functional suitability:

It refers to the purpose of a product. More functions in a product mean it will be more complicated.

Efficiency:

It refers to the resources in the system to offer the required functions. It includes disk space, network, memory, etc.

Maintainability:

It refers to the ability to fix faults in the software. It is impacted by the modularization of the software and the readability of the code.

Note: Other given options such as performance efficiency is related to other mentioned factors such as freedom from risk, effectiveness, satisfaction, and security.

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3-Two main problems important for all of the software architecture principles:

Separation of concerns problems:

If the program is written in one block, it can cause various problems in terms of security, testing, and maintainability. Such a code develops high coupling among the modules.

It is very important that the program is not written as one block. Program should be broken into modules and every single piece should be finalized for different kinds of jobs. It involves two concepts cohesion and coupling. According to separation of concerns the coupling should be reduced and the cohesion should be increased.

• Cohesion refers to the similarity of tasks as per the details and how strong they are connected.
• Coupling measures the dependency of different components of system on each other.
• With loose coupling and high cohesion, code becomes clear.
• It helps in achieving separation of concerns too.
• The code becomes easier to understand and can be reused effectively.
• The testing of modules also becomes easier.

The project can be organized easily and new updates can be introduced as and when required.

Single responsibility principle:

If one class or module is made responsible for various functions in the software, it can make it hard to perform the functions accurately. Every module of the program should take over a single responsibility. It should deal with one type of functionality only. It is also important when there are a number of classes in the program.

• It helps in protecting classes from various kinds of modifications as the program is maintained.
• Here, a class is made responsible for one actor or requirement.
• It also helps in understanding the code easily and classes can be maintained without much efforts.
• Classes can be reused easily.

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5-Difference between external and internal product quality:

• Internal product quality deals with monitoring of the daily precision and correctness of different methodologies. External product quality refers to long term correctness based on outer results.
• Internal quality refers to the design of the overall software. External quality deals with the purpose of the entire software.
• Internal quality makes sure that modifications can be made easily in the system. External quality deals with testing of bugs and errors upon product release.
• Internal quality is the maintaining of everything the customer never gets to see. External quality deals with the user’s view of the software.
• Internal quality includes low coupling, cohesion, clarity, generality, etc. External quality includes reliability, robustness, accuracy, etc.

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6-Software architecture patterns for a distributed environment where the system needs multiple expertise:

Layered pattern:

In a layered pattern, work is divided into layers to accomplish subtasks of various processes. All the layers are different from one another. They can work simultaneously. Higher-level layers use services offered by lower-level layers.

Client-server pattern:

In this pattern there are many distributed nodes called clients, and on centralized node called server. The server offers services to all the clients based on their requirements. All the clients can send their requirest at the same time and for different tasks. Client and server make use of different processors. There can be one or more servers in the system.

Master-slave pattern:

In a master-slave pattern, there are many nodes. Master is responsible for distributing several tasks among nodes called slaves. It is similar to parallel computing. It follows divide and rule notion. After all the slave nodes have fashioned their tasks, the master gathers the output from all of them.