C952 Computer Architecture

Explanation:

Pipelining allows instructions to be overlapped in execution stages. If four sets of instructions are executed using pipelining, each new instruction enters the pipeline before the previous one has finished. In an ideal pipeline with perfect stage utilization, the speedup for N instructions is roughly equal to the number of stages, assuming minimal stalls. For four sets of instructions, they would complete approximately 4 times faster compared to non-pipelined sequential execution because the pipeline allows multiple instructions to be processed simultaneously at different stages.

Correct Answer:

4 times

Why Other Options Are Wrong:

16 times is incorrect because this overestimates the speedup; pipelining does not multiply performance by the square of the number of instructions—it roughly provides linear speedup proportional to the number of pipeline stages.

8 times is incorrect because this also overestimates the speedup; the improvement for four instructions would not reach 8x unless multiple pipeline levels and perfect parallelism are assumed, which is unrealistic.

2 times is incorrect because this underestimates the performance gain; with four instructions and ideal pipelining, the speedup is closer to 4 times, not just 2.

Explanation:

Virtual memory allows a program to use more memory than is physically available in the primary memory (RAM) by temporarily transferring data to secondary storage, such as a hard disk or SSD. This technique enables the execution of large programs or multiple programs concurrently without being limited by the actual physical memory size. By providing an abstraction of a larger memory space, virtual memory improves system flexibility, multitasking capability, and efficient memory management.

Correct Answer:

It permits a program to exceed the size of primary memory

Why Other Options Are Wrong:

It allows reading and writing to main memory in virtual machines is incorrect because while virtual memory involves memory access, its primary advantage is not specific to virtual machines but to enabling larger logical memory spaces.

It shares a virtual address with the same physical address is incorrect because virtual memory typically maps virtual addresses to different physical addresses; sharing the same address defeats the purpose of abstraction and isolation.

It increases the size of the primary memory available is incorrect because virtual memory does not increase physical memory; it provides an illusion of a larger memory space by using secondary storage.

Explanation:

Code efficiency in a pipelined processor is often determined by how effectively instructions flow through the pipeline without stalls or hazards. When the frequency of pipeline hazards is lower, there are fewer situations where instruction execution must be delayed due to data, control, or structural conflicts. This allows the CPU to achieve higher throughput, minimize idle cycles, and utilize resources effectively, making the code execution more efficient than conventional code that might not optimize for hazard reduction.

Correct Answer:

Frequency of pipeline hazards is lower

Why Other Options Are Wrong:

Usage of LEGv8 architecture code is incorrect because while LEGv8 is a modern RISC architecture, merely using LEGv8 instructions does not inherently make code more efficient unless pipeline hazards and instruction scheduling are properly optimized.

Usage of Multimedia extensions (MMX) is incorrect because MMX improves performance for certain multimedia operations, but it does not universally make code more efficient for all instruction types, especially in non-multimedia contexts.

Frequency of pipeline hazards is higher is incorrect because higher pipeline hazards create more stalls, delays, and inefficiencies in instruction execution, which reduces performance rather than increasing code efficiency.

Explanation:

In LEGv8 architecture, the Exception Syndrome Register (ESR) is used to store information about the cause of an exception.

When an exception occurs, the processor automatically populates the ESR with a code that identifies the type of exception, such as an illegal instruction, memory access violation, or system call. This allows the operating system or exception handler to determine the appropriate response and take corrective actions based on the exception type.

Correct Answer:

ESR

Why Other Options Are Wrong:

FSUBS is incorrect because this is a floating-point subtraction instruction, not a register for storing exception information. It performs arithmetic operations and has no role in exception handling.

FADDS is incorrect because this is a floating-point addition instruction and does not store exception information. It is unrelated to handling exceptions in the processor.

RAID is incorrect because RAID typically refers to a storage configuration (Redundant Array of Independent Disks) and is not a processor register in LEGv8 architecture.

Explanation:

The Arithmetic Logic Unit (ALU) performs arithmetic and logic operations, but it requires data to operate on and a place to store results. The register file provides this storage for operands and results, making it essential for ALU operations. Together, the ALU and register file form the core computational elements within a processor, enabling efficient execution of instructions. Without the register file, the ALU would have no immediate access to operands or a place to store results, rendering it unable to function effectively.

Correct Answer:

ALU and register file

Why Other Options Are Wrong:

ALU and GPU is incorrect because a GPU is a specialized processor for graphics operations and is not required for general ALU operations in a CPU. The ALU operates independently of a GPU for standard arithmetic and logic tasks.

Datapath and COD is incorrect because COD is not a standard computer architecture component, and while the datapath is involved in executing operations, it cannot perform ALU functions without the ALU itself and the register file.

GPU and register file is incorrect because a GPU is not necessary for the ALU to perform basic processor operations. The ALU and register file are the essential components for implementing arithmetic and logic functions within the CPU.

Explanation:

The temporal locality principle refers to the tendency for a recently accessed data location to be accessed again in the near future. This principle underlies caching strategies and memory hierarchies in computer systems, where recently used data is kept in faster, more accessible storage to reduce access time. Temporal locality is fundamental in predicting which data should remain in cache, optimizing performance, and minimizing repeated memory fetches. In contrast, other forms of locality, such as spatial locality, relate to accessing nearby memory locations rather than revisiting the same location.

Correct Answer:

Temporal

Why Other Options Are Wrong:

Spatial is incorrect because spatial locality refers to accessing memory locations that are physically near previously accessed locations, not the same location being accessed repeatedly.

Residual is incorrect because this term does not describe a standard locality principle in computer architecture. It has no relevance to memory access patterns or caching strategies.

Canonical is incorrect because canonical locality is not a recognized principle in memory hierarchy or caching theory. It does not relate to repeated data access.

Explanation:

RAID 0 (striping) is a storage configuration that splits data evenly across two or more drives to increase read and write performance. By distributing the data in parallel, multiple disks can be accessed simultaneously, reducing latency and improving overall throughput. Unlike other RAID levels, RAID 0 does not provide data redundancy or fault tolerance, so if one disk fails, all data in the array is lost. Its primary purpose is to maximize storage performance rather than to protect data.

Correct Answer:

Performance enhancement

Why Other Options Are Wrong:

Data redundancy is incorrect because RAID 0 provides no redundancy; all data is split across disks without duplication.

Data backup is incorrect because RAID 0 does not preserve copies of data; it only enhances speed. Users must implement separate backup solutions.

Fault tolerance is incorrect because RAID 0 offers no protection against disk failure; the failure of any single disk results in the loss of all data in the array.

Explanation:

DDR3 memory features 240 pins and provides several improvements over DDR2, including higher data transfer rates, lower power consumption, and improved latency. DDR3 achieves these improvements by operating at lower voltages and using enhanced signaling techniques. This makes DDR3 both faster and more energy-efficient compared to DDR2, which helps improve overall system performance while reducing power usage in desktop and server environments.

Correct Answer:

It features 240 pins and provides improved latency and power efficiency compared to DDR2.

Why Other Options Are Wrong:

It has 288 pins and offers higher data rates than DDR2 is incorrect because 288 pins are associated with DDR4 memory, not DDR3.

It operates at a single data rate per clock cycle, similar to DDR2 is incorrect because DDR3 is a double data rate memory that transfers data on both the rising and falling edges of the clock cycle, like DDR2, but with higher performance and efficiency.

It is primarily used in mobile devices and was introduced in the early 2000s is incorrect because DDR3 is used broadly in desktops, servers, and some laptops; it was introduced later, around 2007, not in the early 2000s.

Explanation:

The CPU generates a significant amount of heat during operation and typically requires its own dedicated fan or heatsink-fan assembly for effective cooling. This fan is designed to maintain the CPU at safe operating temperatures, ensuring stable performance and preventing thermal damage. While other components like PCIe cards or storage devices may have passive cooling or rely on system fans, the CPU almost always has an active cooling solution due to its high power density.

Correct Answer:

CPU

Why Other Options Are Wrong:

USB is incorrect because USB ports and devices generally do not generate enough heat to require their own dedicated fan. They rely on system airflow for cooling.

SATA is incorrect because SATA drives, such as HDDs or SSDs, may produce some heat but typically do not require dedicated fans; they are cooled by case airflow.

PCIe is incorrect because while some high-end graphics cards (a type of PCIe device) may have their own fans, the term “PCIe” refers to the slot or interface in general, not a component that universally requires its own fan.