Operating Systems & Computer Architecture CT049-3-1-OS&CA Ver: VE CPU and Memory Topics

CPU Registers and Components

• The Program Count Register (PC) holds the memory address of the next instruction to be fetched.
• The Instruction Register (IR) stores the current instruction being executed.
• The Memory Data Register (MDR) temporarily holds data being transferred between the CPU and memory.

Memory Capacity

• The memory capacity is determined by the number of address lines and the number of bits in each word.

RAM

• Dynamic RAM (DRAM) requires refreshing thousands of times each second to maintain the stored data.

ALU

• The Arithmetic Logic Unit (ALU) performs arithmetic and logical operations, such as addition, subtraction, AND, and OR.

Control Unit

• The control unit retrieves and decodes instructions, generates control signals, and manages data flow between components.

Registers

• Registers in a CPU are small amounts of on-chip memory that store data temporarily while it is being processed.
• The purpose of registers is to provide quick access to data and reduce the time it takes to access memory.

Control Unit Function

• The control unit is responsible for supervising the fetch-decode-execute cycle, which includes fetching instructions and data from memory.

General Purpose Registers

• General Purpose Registers in a CPU are used to store both data and addresses, and are used for various operations, such as arithmetic and logical instructions.

Test your knowledge of CPU components, memory unit, fetch-execute cycle, buses, instructions, and word formats in the context of operating systems and computer architecture.