IGCSE Computer Science Notes (2)

Why is the binary system essential for computers?

Any form of data must be converted to binary to be processed by a computer.

What is the denary number system?

A base 10 system that uses digits from 0 to 9.

What are the two possible values in the binary number system?

0 (OFF) and 1 (ON).

How is the hexadecimal number system structured?

It is a base 16 system that uses values from 0 to 9, followed by A to F (10 is A, 11 is B, and so on up to 15 is F).

What is the process for converting denary to binary?

Write down the powers of 2 from right to left until 128, and place 1 or 0 according to whether the power of 2 is less than or equal to the number being converted.

What is the first step in converting binary to denary?

Write down the powers of 2 in binary from right to left until 128.

How do you convert binary to hexadecimal?

Group the binary digits into groups of 4, from the rightmost digit, and replace each group with its corresponding hexadecimal value.

What is one advantage of hexadecimal over binary?

Hexadecimal is easier for humans to understand than binary, as it represents binary in a shorter format.

What happens during a binary overflow error?

An overflow error occurs when a value greater than what can be represented in an 8-bit register is returned.

What is a logical left shift in binary?

It multiplies the binary number by a power of 2, shifting bits to the left and introducing zeros on the right.

How does two’s complement work for negative numbers?

Invert all bits of the positive equivalent and add 1 to the resultant binary representation.

What is Unicode?

A character set that supports a greater range of characters and symbols compared to ASCII.

What is the impact of sampling rate on digital sound quality?

Higher sampling rates result in more accurate recordings but also larger file sizes.

What is resolution in relation to images?

Resolution refers to the number of pixels in an image; higher resolution leads to sharper and more detailed images.

What is a nibble in data measurement?

A nibble is a group of 4 bits.

What type of memory is RAM?

Volatile memory that temporarily stores data, instructions, and software currently in use.

What is cloud storage?

Storage that can be accessed remotely, as opposed to being stored locally.

What is the main function of the CPU?

To process data and execute instructions that are input into the computer.

What is a router's primary function?

To analyze data packets and send data to a specific destination on a network.

What is an actuator in output devices?

A component that converts electrical signals into mechanical processes.

What is the purpose of error detection methods like parity checks?

To determine whether bits in transmission have been corrupted.

How does asymmetric encryption work?

It uses two keys: a public key available to everyone and a private key known only to the user.

What does a checksum do?

It is a value calculated from block data to verify the integrity of the data when received.

What type of attack is DDoS?

A flood of a server with requests, causing disruption or making it unavailable.

What is the function of an IDE?

It aids programmers in writing and testing software by providing features like code editors and translators.

What is the difference between high-level and low-level programming languages?

High-level languages use English-like syntax for easier understanding, whereas low-level languages are closer to machine code.