Test: Computer System - Grade 9 MCQ

The Internal Storage Unit is responsible for holding the input data, intermediate results, output results, and program. It makes the stored information available for processing as and when required. Here is a detailed explanation:
Function of Internal Storage Unit:
The Internal Storage Unit, also known as the primary memory or main memory, has the following functions:
1. Storage of Input Data: When data is entered into the computer system through input devices, such as keyboards or mice, it is temporarily stored in the internal storage unit.
2. Storage of Intermediate Results: During the execution of a program, the internal storage unit holds intermediate results generated by the computer's processor.
3. Storage of Output Results: Once the processing is complete, the internal storage unit holds the output results before they are displayed or transferred to an output device.
4. Storage of Programs: The internal storage unit holds the instructions of a program that is being executed by the computer's processor.
5. Access and Retrieval: The internal storage unit allows for quick access and retrieval of data and instructions required for processing.
6. Temporary Storage: The internal storage unit provides temporary storage for data and instructions. It is volatile memory, meaning it loses its contents when the power is turned off.
7. Fast Processing: The internal storage unit enables faster processing of data compared to secondary storage devices like hard drives or solid-state drives.
Components of Internal Storage Unit:
The internal storage unit consists of the following components:
1. Random Access Memory (RAM): This is the primary memory that stores data and instructions currently being used by the processor. It provides faster access to data but is volatile.
2. Cache Memory: Cache memory is a small, high-speed memory that stores frequently used data and instructions to speed up processing.
3. Registers: Registers are small, high-speed storage locations within the processor. They hold the most frequently accessed data and instructions for immediate processing.
4. Virtual Memory: Virtual memory is a technique that uses a portion of the computer's hard drive as an extension of the primary memory. It allows for efficient management of larger programs and data sets.
In conclusion, the internal storage unit plays a crucial role in holding and managing input data, intermediate results, output results, and programs in a computer system. It ensures that the necessary information is readily available for processing by the computer's processor.

Thermal Printers print images by selectively heating coated thermochromic paper which is commonly known as thermal paper. Laser printers prints by using the electrostatic digital printing process.

Dot-Matrix Printer
A dot-matrix printer is a type of printer that uses a print head containing banks of pins to create characters and images on paper. Here is a detailed explanation of how a dot-matrix printer works:
Print Head:
- The print head of a dot-matrix printer consists of a series of pins arranged in a grid.
- These pins are connected to solenoids or tiny electromagnets that control their movement.
- The pins can move in and out rapidly, striking an inked ribbon and paper to create printed characters or images.
Inked Ribbon:
- The inked ribbon is placed between the print head and the paper.
- The ribbon is made of fabric or plastic and is coated with ink.
- When the pins strike the ribbon, they transfer ink onto the paper, creating the desired print.
Paper Feed:
- The paper is fed through the dot-matrix printer using a tractor feed or friction feed mechanism.
- The tractor feed uses sprockets or gears to pull the paper through the printer.
- The friction feed system uses rubber rollers to grip and advance the paper.
Printing Process:
- The dot-matrix printer operates by selectively activating the pins in the print head.
- When a character or image needs to be printed, the printer receives data from the connected device.
- The pins in the print head are then controlled to strike the inked ribbon and paper in specific patterns, forming the desired shapes and characters.
- The pins can create a matrix of dots, which when combined, form characters and images.
Advantages and Disadvantages:
- Dot-matrix printers are known for their durability and ability to print through multipart forms.
- They are relatively inexpensive compared to other types of printers.
- However, dot-matrix printers are slower and noisier compared to modern inkjet or laser printers.
- The print quality is also lower, with characters appearing as a series of dots rather than smooth lines.
In conclusion, a dot-matrix printer uses a print head with pins that move at high speed against an inked ribbon and paper to create printed characters and images. It is a reliable and affordable printing option, although it may not offer the same print quality and speed as more modern printers.

The type of memory used in a pen drive is Flash Memory.
Flash memory is a type of non-volatile memory that can be electrically erased and reprogrammed. It is a solid-state storage device that retains data even when the power is turned off. Here are some key points about flash memory:
- Definition: Flash memory is a type of EEPROM (Electrically Erasable Programmable Read-Only Memory) that can be electrically erased and reprogrammed. It is a popular storage medium for portable devices like pen drives, USB flash drives, and solid-state drives (SSDs).
- Operation: Flash memory functions by storing data in memory cells made of floating-gate transistors. The data is written to and read from the cells using electrical voltages. The cells can be programmed (data written) and erased (data deleted) using specialized circuits.
- Advantages: Flash memory offers several advantages, including high speed, small size, low power consumption, and durability. It is resistant to shock, vibration, and extreme temperatures, making it suitable for portable storage devices.
- Usage: Flash memory is widely used in portable storage devices like pen drives, also known as USB flash drives. These small, portable devices can store large amounts of data and can be easily connected to computers and other devices via a USB port.
- Other Applications: Flash memory is also used in various other applications, such as digital cameras, smartphones, tablets, and embedded systems. It has become a popular choice for primary storage in many electronic devices.
In conclusion, the type of memory used in a pen drive is flash memory. This type of non-volatile memory provides portable storage with high speed, small size, and durability, making it ideal for data storage in pen drives and other portable devices.