Computer Science EST revision

What is the role of documentation in the SDLC?

• To ensure that the system is secure

• To maintain the system

• To design the system

• To test the system

Answer explanation

Documentation is an important part of the Software Development Life Cycle (SDLC) as it helps maintain the system and provides information for future maintenance, troubleshooting, and enhancement of the system.

Which notation is used to create context diagrams?

• Use Case diagrams

• Entity-Relationship diagrams

• Yourdon/DeMarco notation

• Flowcharts

Answer explanation

Yourdon/DeMarco notation is a popular notation used to create context diagrams. It is a visual representation of the scope and boundaries of the system and shows external entities and their interactions with the system.

What are the functions of the components of the CPU?

• Input and Output

• Memory and Storage

• Arithmetic Logic Unit and Control Unit

• Operating System and Applications

Answer explanation

The two main functions of the CPU are performed by the Arithmetic Logic Unit (ALU), which performs arithmetic and logical operations, and the Control Unit (CU), which manages the flow of data between the CPU and other components.

Which component of the CPU manages the execution of instructions?

• Arithmetic Logic Unit

• Control Unit

• Registers

• Program Counter

Answer explanation

The Control Unit (CU) manages the execution of instructions by managing the flow of data between the CPU and other components. It fetches the instruction from memory, decodes it, and then executes it.

What is the purpose of a context diagram?

• To identify system requirements

• To identify system inputs, processes, and outputs

• To identify external entities and data flows in a system

• All of the above

Answer explanation

A context diagram is used to show the scope and boundaries of the system and to identify external entities, inputs, processes, and outputs of the system. It helps to understand the requirements of the system and the interactions between different components.

Which step in the fetch-execute cycle involves decoding the instruction?

• Fetch

• Decode

• Execute

• Store

Answer explanation

The fetch-execute cycle is the process used by the CPU to execute instructions. The steps involved are fetch, decode, execute, and store. During the decode step, the instruction is decoded to determine what operation needs to be performed.

Which data protection method converts data into a coded language to prevent unauthorized access?

• Encryption

• Authentication

• Digital Signature

• None

Answer explanation

Encryption is a method used to protect data by converting it into a coded language to prevent unauthorized access. The data can only be accessed by those who have the encryption key to decode the data.

Which data type represents numerical values?

• Text

• Number

• Boolean

• Date/Time

Answer explanation

The data type "Number" is used to represent numerical values such as integers and floating-point numbers.

What is the purpose of a primary key in a database?

• To identify the attributes of an entity

• To ensure data integrity

• To prevent data redundancy

• To uniquely identify each record in a table

Answer explanation

A primary key is a field or set of fields that uniquely identifies each record in a table. It is used to ensure data integrity, prevent data redundancy, and establish relationships between tables in a database.

Systems development documentation is not an essential part of the SDLC.

• True

• False

Answer explanation

Systems development documentation is an essential part of the SDLC. It provides a record of the development process and helps ensure that the system is developed according to requirements.