Hardware and Operating System
Essentials
A Flashcard-Style Study Guide
Key terms and concepts covering CPU architecture, memory and cache,
storage, motherboards, I/O, and core operating system topics including
processes, memory management, file systems, security, and networking.
Original study material prepared for review and practice.
,CPU Architecture & Registers
Program Counter (PC)
A register that holds the memory address of the next instruction to be executed. It
increments automatically after each fetch unless changed by a jump, branch, or call.
Instruction Register (IR)
Holds the current instruction being decoded and executed by the control unit.
Page 1
,Accumulator (ACC)
A general-purpose register used to store intermediate results of arithmetic and logic
operations performed by the ALU.
Memory Address Register (MAR)
Holds the address of the memory location that is about to be read from or written to.
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, Memory Buffer Register (MBR)
Sometimes called the Memory Data Register; temporarily stores data being
transferred to or from memory.
Arithmetic Logic Unit (ALU)
The component of the CPU responsible for performing arithmetic operations
(addition, subtraction) and logical operations (AND, OR, NOT, comparisons).
Page 3
Essentials
A Flashcard-Style Study Guide
Key terms and concepts covering CPU architecture, memory and cache,
storage, motherboards, I/O, and core operating system topics including
processes, memory management, file systems, security, and networking.
Original study material prepared for review and practice.
,CPU Architecture & Registers
Program Counter (PC)
A register that holds the memory address of the next instruction to be executed. It
increments automatically after each fetch unless changed by a jump, branch, or call.
Instruction Register (IR)
Holds the current instruction being decoded and executed by the control unit.
Page 1
,Accumulator (ACC)
A general-purpose register used to store intermediate results of arithmetic and logic
operations performed by the ALU.
Memory Address Register (MAR)
Holds the address of the memory location that is about to be read from or written to.
Page 2
, Memory Buffer Register (MBR)
Sometimes called the Memory Data Register; temporarily stores data being
transferred to or from memory.
Arithmetic Logic Unit (ALU)
The component of the CPU responsible for performing arithmetic operations
(addition, subtraction) and logical operations (AND, OR, NOT, comparisons).
Page 3
