CPU Architecture, Instruction Set Principles, and Computer Fundamentals

Comprehensive vocabulary flashcards covering CPU architecture, instruction set principles, operating system structures, digital computer components, and digital logic circuits.

Operating System (OS)

A program that manages computer hardware, provides a basis for application programs, and acts as an intermediary between the computer user and hardware.

Bootstrap Program

The initial program stored in ROM that executes when a computer is powered up or rebooted; it locates and loads the operating system kernel into main memory.

Interrupt

A hardware or software signal sent to the CPU that causes it to halt current execution and immediately transfer control to an interrupt service routine.

System Call

A special software-triggered operation (also known as a monitor call) that requests services directly from the operating system kernel.

Interrupt Service Routine (ISR)

A predefined software routine located at a fixed memory address that specifies the exact instructions executed to handle a specific interrupt.

Direct Memory Access (DMA)

An I/O technique where the device controller transfers an entire block of data directly to or from its own buffer to main memory without CPU intervention, generating only one interrupt per block.

Multiprogramming

An operating system technique that increases CPU utilization by holding multiple jobs in memory simultaneously, allowing the CPU to execute another program whenever one waits for I/O.

Multitasking (Time-Sharing)

A logical extension of multiprogramming in which the CPU switches between user jobs in small time slots so rapidly that users can interact with each program while it runs.

Mechanism vs. Policy

A fundamental software engineering design separation where mechanisms determine how something is done, while policies determine what will be done.

Microkernel

An operating system structure that strips non-essential components from the kernel and implements them as user-level system programs communicating via message passing.

Computer Architecture

The design and structure of a computer system visible to the programmer/user, including the instruction set, addressing modes, data types, and I/O mechanisms (what the system does).

Computer Organization

The internal operational units and physical interconnections that implement architectural specifications, such as memory technology, control signals, and bus structures (how the system works).

Arithmetic and Logic Unit (ALU)

The functional hardware unit within the CPU that executes arithmetic operations (such as addition and subtraction) and Boolean logical operations.

Control Unit (CU)

The processing component that directs and coordinates the flow of data and instructions between all units of a computer by issuing timed control signals.

Mainframe Computer

A large, powerful computer system designed for multi-user enterprise environments and high-volume, intensive computational tasks such as banking and reservations.

Supercomputer

The most powerful class of computers, utilizing massive multiprocessing and parallel processing architectures to execute complex scientific simulations such as weather modeling.

Macro-operation

A high-level operation defined at the architecture level by an individual machine instruction opcode, which is decomposed into one or more register transfer operations.

Micro-operation

An elementary hardware operation performed on data residing in registers during a single clock cycle, including register transfers, arithmetic, logic, and shifts.

Datapath

The hardware subsystem of a processor responsible for processing and storing data, consisting of the ALU, internal registers, buses, and signal driver/receiver circuits.

Program Status Word (PSW)

A register containing both status flags (reflecting arithmetic/logical operation outcomes) and control flags (governing CPU behavior such as interrupt handling).

Trap Flag (TF)

A processor control flag that enables single-step execution mode for program debugging by generating an internal interrupt after each individual instruction is executed.

XLAT Instruction

A translate instruction that converts a data code from one format or encoding into another using a memory lookup table.

ESC Instruction

A processor control instruction indicating that the subsequent instruction is intended for execution by an attached coprocessor rather than the host CPU.

LOCK Instruction

A bus-control instruction prefix that reserves the shared system bus and memory until the operation immediately following it finishes executing.

Bit

The smallest fundamental unit of binary data, representing one of two discrete electrical states: logic $0$ or logic $1$.

NAND Gate

A universal logic gate representing an inverted AND function ($(A \cdot B)'$) whose output is logic $0$ only when all inputs are logic $1$.

NOR Gate

A universal logic gate representing an inverted OR function ($(A + B)'$) whose output is logic $1$ only when all inputs are logic $0$.

Exclusive-OR (XOR) Gate

A logic gate whose output is $1$ if any single input is $1$, but evaluates to $0$ if both inputs are identical ($0$ and $0$, or $1$ and $1$).

Exclusive-NOR (XNOR) Gate

A logic gate producing an output of $1$ only when both inputs are equal to each other ($0$ and $0$, or $1$ and $1$); the logical complement of the XOR gate.

DeMorgan's First Theorem

A Boolean identity stating that the complement of a logical sum equals the logical product of the individual complements: $(x + y)' = x' \cdot y'$.

DeMorgan's Second Theorem

A Boolean identity stating that the complement of a logical product equals the logical sum of the individual complements: $(x \cdot y)' = x' + y'$.

Minterm

A Boolean product term containing every variable of a function in either complemented or uncomplemented form, corresponding to a single row in a truth table.

Karnaugh Map (K-Map)

A visual, grid-based representation of a truth table used to simplify Boolean expressions by grouping adjacent minterm cells in powers of two ($2^n$).