1.1 Systems Architecture

CPU (Central Processing Unit)

The "brain" of the computer that processes instructions.

Von Neumann Architecture

-Describes how computers are built.

-One memory for both data and instructions.

-Instructions are fetched, decoded, and executed

ALU (Arithmetic Logic Unit)

Performs calculations and logic operations

CU (Control Unit)

Sends control signals and manages the FDE cycle

Program Counter

Holds the memory address of the next instruction to be executed

Accumulator

Stores results of calculations in the ALU

MDR (Memory Data Register)

Holds the data fetched from, or to be written to the memory

MAR (Memory Address Register

Holds the address of where data is to be fetched or stored

Fetch-Decode-Execute Cycle (FDE)

1.Fetch: Get instruction from memory (PC → MAR, then MDR).

2.Decode: CU decodes the instruction.

3.Execute: ALU or other components carry it out.

Clock speed (GHz)

-The speed of microprocessors, called the clock speed, often is measured in gigahertz which is 1 billion cycles per second

-Faster = more instructions per second

Number of cores

The more cores a CPU has, the more instructions it can carry out at once.

Cache size

-Fast access memory that is faster to access than RAM. Stored frequently used instructions

-Bigger cache = faster access to data.