Final answer:
The effective access time (EAT) in computing is directly proportional to the page-fault rate, as a higher rate of page faults increases the average time taken for memory operations due to the need to fetch data from secondary storage.
Step-by-step explanation:
The effective access time (EAT) in a computer system is affected by several factors, particularly when considering a system with virtual memory. EAT is the average time taken for a memory operation, factoring in the possibility of a page fault. When a page fault occurs, the desired data is not in the main memory and must be fetched from secondary storage, which dramatically increases access time.
The correct option that EAT is directly proportional to would be: a) Page-fault rate. The higher the page-fault rate, the greater the chance that any given memory access will require fetching data from secondary storage, hence increasing the effective access time. The hit ratio is actually inversely proportional to EAT, as it represents the proportion of accesses that can be satisfied without having to fetch data from slower storage. Memory access time contributes to the calculation of EAT but is not directly proportional as page faults need to be accounted for in the overall EAT calculation.
Thus, the option a) Page-fault rate is the correct answer. The terms hit ratio, memory access time, and page-fault rate are crucial in understanding the concept of effective access time in computing.