ENG210 Computer Architecture Chapter 5: CPU & Memory

These flashcards cover key concepts related to CPU and memory architecture as described in the lecture notes for ENG210.

What does the ALU stand for and what is its main function?

Arithmetic Logic Unit; it performs calculations and comparisons.

What does the CU in a CPU do?

Control Unit performs the fetch/execute cycle and accesses program instructions.

What is the role of the Memory Management Unit?

It supervises fetching instructions and data from memory.

What is the primary purpose of Registers in a CPU?

Registers serve as small, permanent storage locations used for specific purposes.

What is the function of the Program Counter Register (PC)?

It keeps track of the address of the next program instruction to be executed.

What does the Instruction Register (IR) do?

Stores instructions fetched from memory.

What information does the Memory Address Register (MAR) hold?

It holds the address of the memory location that needs to be accessed.

What is the Memory Data Register (MDR)?

It temporarily holds data that is being transferred to or from memory.

What is the primary function of memory in a computer system?

To hold information temporarily while the processor is acting on it.

What determines the memory capacity of a system?

The number of bits in the MAR and the size of the address portion of the instruction.

Difference between DRAM and SRAM?

DRAM (Dynamic RAM) is cheaper and must be refreshed frequently, while SRAM (Static RAM) is faster and more expensive.

What is ROM?

Read-Only Memory; it holds software that is expected to remain unchanged.

What does EEPROM stand for and what is its function?

Electrically Erasable Programmable Read-Only Memory; it can be reprogrammed and erased electrically.

What are the two phases of the Fetch-Execute Cycle?

Fetch and Execute phases.

What occurs during the Fetch phase of the cycle?

The instruction is located, loaded from memory into the register, and signaled to the ALU.

What is involved in the Execute phase of the Fetch-Execute Cycle?

The operation that the instruction requires is performed.

What are the components of a simple memory address?

The address and value for accessing information.

What is the function of a Bus in computer architecture?

It is a physical connection that enables data transfer between different locations in the system.

What are the types of signals that can be carried on a Bus?

Data, addressing, control signals, and sometimes power.

Identify the two categories of buses based on transmission type.

Parallel and serial buses.

How does the throughput of parallel buses compare to serial buses?

Parallel buses generally have higher throughput because bits are transmitted simultaneously.

What is an OPCODE in the context of instructions?

The operation code that specifies the task to be performed.

What is the difference between explicit and implicit operands?

Explicit operands are included in the instruction while implicit ones are default assumed.

What do addressing modes refer to?

The method used to specify an operand's location in instructions.

What is the significance of Instruction Word Size?

It affects how much data can be processed in a single instruction.

Which type of memory is volatile and must be refreshed continuously?

DRAM (Dynamic RAM).

What is the purpose of the Instruction Set in a computer system?

It defines the functions performed by the processor and differentiates computer architectures.

What does the Fetch Cycle include in its operations?

It involves placing the program counter value into MAR, incrementing the PC, and loading the program line into the IR.

What is the purpose of Flags in Status Registers?

To track conditions like arithmetic carry and overflow.

How does the memory read operation work?

The CPU loads the memory address into the MAR, sends a read signal, and the data is loaded into the MDR.

What happens during a memory write operation?

The CPU loads the address into the MAR, puts data in the MDR, and sends a write signal to store the data.

What defines the characteristics of a Bus?

The number of conductors, data width, addressing capacity, and throughput.

What are Multipoint Buses?

Buses that connect multiple points together.

What distinguishes half duplex from full duplex buses?

Half duplex allows data transmission in one direction at a time, while full duplex allows simultaneous bidirectional transmission.

What is the definition of a control signal in a bus?

A signal that controls the operations of devices on the bus.

How are instruction sets essential for computer architecture?

They define the operations that the processor can perform and impact performance and capability.

What is the function of the accumulator in the fetch/execute cycle?

It temporarily holds data that is being processed.

What can cause electrical interference in parallel buses?

Radio-generated electrical interference.

What is the purpose of architecture-specific instruction formats?

To specify the layout and parameters of instructions within a computer architecture.

What is Instruction Format?

A machine-specific template that specifies the length of the op code and the number of operands.

Why is pipelining important in modern CPU architecture?

Pipelining increases instruction throughput by allowing multiple instructions to overlap in execution.

What is an example of a single operand manipulation instruction?

Negating, decrementing or incrementing a value.

Define the term 'bus throughput.'

It is the data transfer rate of a bus, measured in bits per second.

Explain what a control unit does in the CPU.

It orchestrates the operations of the CPU components and the execution of instructions.

What is the main difference between volatile and nonvolatile memory?

Volatile memory loses its data when power is off, while nonvolatile memory retains its data.