Mixed Questions

Statement 1 and 2: correct

• OS allows the computer to manage its own resource such as memory, keyboard and printer

Statement 3: correct

• OS provides the user an easy to work user interface, so the user doesn’t have to learn a different UI every time.

Statement 4: correct

• Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory (RAM), independent of the central processing unit (CPU)
• Disk drive is a hardware subsystem

SRAM (static RAM) is random access memory (RAM) that retains data bits in its memory as long as power is being supplied.

Inside a dynamic RAM chip, each memory cell holds one bit of information and is made up of two parts: a transistor and a capacitor.

• For most computer languages, the name of the file that holds the source code to a program is immaterial
• However, in Java the name given to a source file is very important
• The Java compiler requires that a source file uses the .java filename extension
• Only file.java follow the properties in the given options
• In Java, a source file is officially called a compilation unit; It is a text file that contains one or more class definitions

The correct answer is a Business database.

Key Points

Business Database:

• A business database contains business customers’ past purchases; past volumes, prices, and profits.
•  It also contains buyer team remembers names (and ages, birthdays, hobbies, and favorite foods); status of current contacts; an estimate of supplier’s share of the customer’s business; competitive suppliers; assessment of competitive strengths and weakness in selling and servicing the account; and relevant customer buying practices, patterns, and policies.
• It is considered as a cloud where all the information is stored and kept for use.

The correct answer is option 1.

Concept:

Weak entity set :

A weak entity set is an entity set that does not contain sufficient attributes to uniquely identify its entities. In other words, a primary key does not exist for a weak entity set. However, it contains a partial key called a discriminator. Discriminators can identify a group of entities from the entity set.

ER diagram:

This ER diagram illustrates key information about the book, including entities such as author, Publisher, books, and Edition. It allows for understanding the relationships between entities.

Author:

For an author, the book dealer might want to keep track of the name (first, middle, and last), date of birth, and date of death.​

Publisher: 

For a Publisher, the book dealer might want to keep track of the phone, name, and address.

Book:

For a book, the book dealer might want to keep track of the id, title, and date.

Edition:

For an edition, the book dealer might want to keep track of the name and the total number of copies.

Relation ER diagram,

• The author can write a number of books and each number of books has many numbers of authors. So it has many to many relationships.
• The book can publish at most one publisher and each number of publishers has many numbers books. So it has many to one relationship.
• The book can has atmost one edition and each number edition has many numbers of books. So it has many to one relationship.

The ER diagram,

Here Edition is a weak entity because it can not have candidate key attributes.​

Hence the correct answer is Edition.

There are 4 library functions provided by C defined under header file to facilitate dynamic memory allocation in C programming. They are:

• malloc()
• calloc()
• free()
• realloc()

• In SQL, the function - avg, min, max, sum, count is called as aggregate function.
• Aggregate functions return a single value after calculating from a group of values.
• avg() function returns the average values, max() returns the maximum value, count() finds the number of rows that matches the specified condition, min() returns the minimum value, Max() returns the maximum value. sum() returns the sum of values.

Example:

SELECT AVG(salary

FROM employees

GROUP BY department_id;

The correct answer is Input.

• Devices that enter information into the computer and communicate with it are called Input devices.

Key Points

• An input device is a peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or other information appliance.
• The Central Processing Unit (CPU) of a computer receives the input and processes it to produce the output.

Additional Information

• Examples of input devices include
  • Keyboards, mouse, scanners, digital cameras, joysticks, Microphone, TouchPad, Webcam, remote, biometric devices, etc.
• Keyboard is a basic input device that is used to enter data into a computer or any other electronic device by pressing keys.
• Mouse is a hand-held input device that is used to move cursor or pointer across the screen. 
• Scanner uses the pictures and pages of text as input. 

The correct answer is Video Graphics Array.

• VGA is Video Graphics Array which is a computer chipset standard for displaying colour graphics. 
• VGA is a popular display standard developed by IBM and introduced in 1987.
• It provides 640 x 480 resolution color display screens with a refresh rate of 60 Hz and 16 colors displayed at a time. 
• VGA utilizes analog signals, which means it's only capable of lower resolutions and a lower quality display on screens.

• The VGA connector is used for display devices and is used to connect a computer to a monitor, projector, or TV.