Cambridge 9618 AS Computer Science - Number Systems

Vocabulary flashcards covering Cambridge 9618 AS Computer Science course structure and Unit 1 number representation concepts including denary, binary, and hexadecimal number systems and conversion techniques.

Denary (Base 10)

A numbering system that utilizes the digits $0$ through $9$, with column place values increasing as powers of ten ($\times 10^n$).

Binary (Base 2)

A numbering system that uses only two digits, $0$ and $1$, with column place values increasing as powers of two ($\times 2^n$).

Hexadecimal (Base 16)

A numbering system that utilizes sixteen symbols consisting of digits $0$ through $9$ followed by letters $\text{A}$ through $\text{F}$, with column place values increasing as powers of sixteen ($\times 16^n$).

Nibble

A data unit consisting of exactly $4$ binary bits, which directly represents one hexadecimal digit.

Subscript (in Number Systems)

A small number notation placed at the base of a numerical value to specify its base system (for example, $173_{10} = 10101101_2 = \text{AD}_{16}$).

Place-Value Method (Denary to Binary)

A conversion process in which powers of $2$ ($128, 64, 32, 16, 8, 4, 2, 1$) are listed, and the largest power less than or equal to the remaining value is repeatedly subtracted, writing a $1$ where it fits and a $0$ elsewhere until the remainder reaches $0$.

Binary to Denary Conversion

A conversion process in which place values ($128, 64, 32, 16, 8, 4, 2, 1$) are written above each bit and only the values aligned with a $1$ are added together.

Hexadecimal Digits A through F

The letters used in base $16$ to represent two-digit denary values: $\text{A} = 10$, $\text{B} = 11$, $\text{C} = 12$, $\text{D} = 13$, $\text{E} = 14$, and $\text{F} = 15$.

Binary to Hexadecimal Conversion

The method of converting a binary number into hexadecimal by grouping bits into sets of $4$ (nibbles) from right to left and replacing each nibble with its equivalent hexadecimal digit.

Leading Zero Padding

The technique of prefixing zeros to the leftmost end of a binary string so that its length becomes an exact multiple of $4$ before splitting into nibbles.

Memory Dump

A display of computer memory contents typically shown to engineers in hexadecimal rather than binary because hexadecimal represents binary data in a much more compact and readable format.