3. CPU

CPU (Central Processing Unit)

The main brain of the computer that fetches, reads, and executes program instructions.

ALU (Arithmetic Logic Unit)

The math part of the CPU that does calculations (like adding/subtracting) and basic logic checks on binary numbers.

Control Unit (CU)

The manager of the CPU that pulls instructions from memory, figures out what they mean, and directs the other parts on what to do.

Registers

Super fast, tiny storage slots built right inside the CPU core to hold data the processor is using at that exact microsecond.

Accumulator

The most active register in the CPU, used to quickly hold temporary math results while calculations are being made.

MAR (Memory Address Register)

The register that holds the physical address location of the next piece of data the CPU needs to grab from memory.

MDR (Memory Data Register)

The register that holds the actual data that was just read from memory, or the data waiting to be saved into memory.

Program Counter (PC)

A tracker register that holds the memory address of the very next instruction waiting in line to be processed.

Instruction Register (IR)

The specific placeholder register that holds the exact instruction the CPU is actively working on right now.

Pipelining

A speed trick where the CPU overlaps its steps—fetching the next instruction while decoding the current one—to get more work done faster.

32-bit vs 64-bit Data Path

How much data the CPU can move at once. 32-bit can only handle up to 4GB of RAM, while 64-bit can handle an enormous amount (up to 16 Exabytes).

CISC (Complex Instruction Set Computing)

A CPU style (like standard Intel x86) that uses large, complex commands to prioritize matching and running older software.

RISC (Reduced Instruction Set Computer)

A CPU design that uses a small, highly optimized set of simple commands to get tasks done at lightning speed.

ARM (Advanced RISC Machines)

A specific type of RISC processor built to use very little battery power, making it perfect for phones, tablets, and modern laptops.