Data Storage and Representation

Practice vocabulary flashcards covering computer data storage, bit representations, logic circuits, memory addressing, endianness, number systems, and storage media from Chapter 1 lectures.

Bit (Binary Digit)

The most fundamental unit of information in digital computing, representing one of two states denoted as $0$ or $1$ (or false and true).

Boolean Operation AND

A fundamental logic operation that yields an output of $1$ only when both input operands are $1$, producing $0$ in all other cases.

Boolean Operation OR

A fundamental logic operation that yields an output of $1$ if at least one input operand is $1$, producing $0$ only when both inputs are $0$.

Boolean Operation XOR (Exclusive OR)

A logic operation that produces an output of $1$ when the two input bits differ, and an output of $0$ when both inputs are identical ($0$ and $0$, or $1$ and $1$).

Logic Gate

A hardware building block in digital circuits that computes a Boolean operation, where the binary values $0$ and $1$ are physically represented by distinct voltage levels.

Flip-flop Circuit

A fundamental digital circuit that produces an output value of $0$ or $1$ that remains constant until a temporary external pulse shifts it to the other value.

SR Latch (Set-Reset Latch)

A fundamental memory circuit constructed using cross-feedback logic gates that stores a bit of information based on temporary set and reset input signals.

Magnetic-core Memory

The predominant form of random-access computer memory between about $1955$ and $1975$, which stored bits via tiny ferrite rings magnetized in one of two directions.

Dynamic Memory

A semiconductor memory technology where bits are stored as electric charges on microscopic capacitors on an integrated circuit chip.

Refresh Circuit

A supporting electronic circuit in dynamic memory systems that repeatedly restores dissipating electrical charges stored on capacitors to avoid data loss.

Byte

A small cell of computer memory storage typically comprised of a contiguous pattern of $8$ bits.

Hexadecimal Coding System

A base-$16$ shorthand notation using the symbols $0$ through $9$ and $A$ through $F$, where each symbol represents a pattern of exactly $4$ bits.

Memory Cell Address

A unique identifying integer assigned to each memory cell on a byte-addressable system that allows programs and the CPU to target specific storage locations.

Random Access Memory (RAM)

Volatile main semiconductor memory organized into addressable cells that can be read from or written to directly in approximately equal time regardless of physical location.

Big-endian

An architectural memory convention where the most-significant (leftmost) byte of a multi-byte integer is stored at the lowest (initial) memory address.

Little-endian

An architectural memory convention where the least-significant (rightmost) byte of a multi-byte integer is stored at the lowest (initial) memory address.

Hex Dump

A tabular visual display of raw memory used by debuggers and hex editors, presenting bytes in hexadecimal across rows (often $16$ per line) preceded by the starting row address.

C Data Type char

An integer data type in the C programming language that typically occupies $1\,\text{byte}$ ($8\,\text{bits}$) of memory.

C Data Type short

An integer data type in the C programming language that typically occupies $2\,\text{bytes}$ ($16\,\text{bits}$) of memory.

C Data Type int

The default integer type in the C programming language that typically occupies $4\,\text{bytes}$ ($32\,\text{bits}$) and represents integers roughly in the range from $-2\,\text{billion}$ to $+2\,\text{billion}$.

C Data Type long

An extended integer type in the C programming language that typically occupies $8\,\text{bytes}$ ($64\,\text{bits}$), chosen when variables must store numbers larger than $2\,\text{billion}$.

Memory Padding

Unused bytes inserted between allocated variables by a compiler to align data on specific hardware boundary offsets for architectural optimization.

Magnetic Disk Track

One of the concentric circular rings on the surface of a magnetic disk platter along which data bits are recorded.

Magnetic Disk Sector

A physical subdivision of a disk track containing a uniform block of data, specified in the notes as typically holding $512\,\text{KB}$ or $1024\,\text{KB}$.

Disk Formatting

The physical and logical initialization procedure that establishes the positions and layout of tracks and sectors on a disk storage medium.

Seek Time

The performance metric measuring the mechanical delay required for a disk drive's read/write head to move across platters to the target track.

Latency Time (Rotational Delay)

The rotational delay required for the desired sector on a magnetic disk platter to rotate underneath the positioned read/write head.

Transfer Rate

The rate at which data bits are actively transmitted to or read from a mass storage device once the read/write mechanism is fully positioned.

Magnetic Tape

A sequential mass storage medium utilizing a ribbon of magnetic tape, offering minimal random access but providing a cost-effective solution for offline archives.

Physical Record

A block of data on a mass storage medium whose size and organization conform to the physical hardware characteristics of the storage device.

Logical Record

A division of data within a file determined by the natural meaning, structure, and semantic boundaries of the represented information.

Buffer

An intermediate memory holding area used to temporarily store blocks of data during transfer between mass storage and running programs, resolving issues with scattered data.

ANSI

The American National Standards Institute, a standards body that oversees the development of voluntary technical and encoding standards in the United States.

ISO

The International Organization for Standardization, a worldwide federation that coordinates global technical and data representation standards.

ASCII

The American Standard Code for Information Interchange, an encoding standard that assigns specific numeric values to characters, punctuation, and control commands.

Non-printing ASCII Characters

The first $32$ codes (decimal $0$ to $31$) in the ASCII character table, originally designed to control teletype hardware actions such as carriage return (CR) or line feed (LF).

Extended ASCII

A series of $8$-bit character encodings that utilize codes $128$ through $255$ to represent regional alphabetic characters, box-drawing symbols, and mathematical notation.

Radix Point

The delimiter symbol separating the whole number part from the fractional part in a positional numeral system, such as the decimal point in base-$10$ or the binary point in base-$2$.

Decimal-to-Binary Fraction Conversion

A step-by-step conversion method where a decimal fraction is repeatedly multiplied by $2$, extracting the whole number part ($0$ or $1$) at each step as the next binary digit.

Two's Complement Notation

The standard fixed-width binary encoding system used to represent signed integers in computers, allowing subtraction to be performed with standard addition circuitry.

Sign Bit

The leftmost (most-significant) bit in signed integer representations, where a value of $0$ represents a non-negative integer and $1$ represents a negative integer.

Two's Complement Overflow

An arithmetic error that occurs when a mathematical operation yields a result outside the representable range of a fixed-width two's complement field, corrupting the sign bit.

Floating-point Notation

A representation standard for real numbers and fractions that encodes values using three separate fields: a sign bit, an exponent, and a mantissa.

Mantissa

The significand field of a floating-point number that represents the significant binary digits of the numeric value.

Exponent (Floating-point)

The component in floating-point notation that specifies the power of the base by which the mantissa is scaled, indicating the position of the radix point.

Truncation Error

A mathematical error that occurs when a fractional value cannot be recorded with complete precision due to the finite number of bits allocated to the mantissa.

DVD-ROM

A mass-produced, read-only optical disc format where stored data cannot be overwritten, modified, or used to record new play data.

DVD-RAM

A rewritable optical disk standard that functions as read-write media, allowing stored software or files to be repeatedly changed and overwritten.

Hard Disk Drive (HDD)

A non-volatile mass storage device utilizing spinning magnetic platters that delivers fast sequential data access but slower random access due to head positioning overhead.

Volatile Memory

A class of computer memory, such as RAM, that requires a continuous electrical power supply to retain stored data and loses its contents as soon as power is turned off.