Data Representation – Key Vocabulary

Vocabulary flashcards covering key terms and concepts from the lecture on Data Representation, including number systems, binary arithmetic, storage units, character encoding, and error conditions.

Denary (Decimal) Number System

Base-10 numbering system that uses the digits 0–9.

Binary Number System

Base-2 numbering system that uses only the digits 0 and 1.

Binary Place Value

Each bit’s value is a power of two (…128, 64, 32, 16, 8, 4, 2, 1).

Bit

The smallest unit of data; a single binary digit (0 or 1).

Nibble

A group of 4 bits (half a byte).

Byte

A group of 8 bits.

Kilobyte (kB)

Approx. 1 000 bytes using decimal prefixes (IEC: kibibyte ≈ 1 024 bytes).

Kibibyte (KiB)

1 024 bytes, the binary-prefix version of a kilobyte.

Megabyte (MB)

Approx. 1 000 000 bytes; binary equivalent is mebibyte (MiB ≈ 1 048 576 bytes).

Gigabyte (GB)

Approx. 1 000 000 000 bytes; binary equivalent is gibibyte (GiB ≈ 1 073 741 824 bytes).

Terabyte (TB)

Approx. 1 000 000 000 000 bytes; binary equivalent is tebibyte (TiB).

Binary-to-Denary Conversion

Sum the products of each bit and its power-of-two place value.

Denary-to-Binary Conversion

Repeated division by 2 (track remainders) or fill place-value columns with 1s and 0s.

Binary Addition

Add bits column-wise; 1+1=10, carrying the 1 to the next column.

Binary Subtraction

Subtract bits column-wise; borrow from higher place values when needed.

Overflow Error

Occurs when a calculation produces a value too large for the fixed number of bits (word size).

Word Size

The number of bits a CPU register can hold (e.g., 8-, 32-, or 64-bit).

Unsigned Binary Number

Binary value assumed to be non-negative; all bits represent magnitude.

Signed Binary Number

Binary value that may be positive or negative, indicated by a sign method (e.g., MSB).

Most Significant Bit (MSB)

Left-most bit in a binary number; often used as the sign bit in signed formats.

Sign and Magnitude

Signed format where MSB represents sign (0=+ , 1=-) and remaining bits give magnitude.

One’s Complement

Invert every bit (0→1, 1→0) to represent the negative of a binary number.

Two’s Complement

Invert all bits then add 1; standard method for signed integers in computers.

Hexadecimal Number System

Base-16 system using digits 0–9 and letters A–F.

Binary–Hex Conversion

Group binary digits in sets of four; map each quartet to one hex digit (and vice versa).

Hexadecimal-to-Denary Conversion

Sum each hex digit multiplied by its power-of-16 place value.

Denary-to-Hexadecimal Conversion

Repeatedly divide the denary number by 16; collect remainders as hex digits.

Binary Coded Decimal (BCD)

Encoding where each decimal digit is stored in its own 4-bit binary pattern.

Packed BCD

Stores two decimal digits per byte—one digit per nibble.

Unpacked BCD

Stores one decimal digit per byte; upper nibble is unused.

ASCII (American Standard Code for Information Interchange)

7-bit character code mapping 128 symbols (letters, digits, control codes).

Extended ASCII

8-bit superset of ASCII providing 256 code points for additional symbols.

Unicode

Universal character-encoding standard assigning a unique code point to over 128 000 characters.

Code Point

Numeric value assigned to a character in Unicode, written as U+ followed by hex digits.

Network Interface Card (NIC) Address

Unique 48-bit identifier (often displayed in hexadecimal) assigned to network hardware.