Consider a Direct Mapped Cache with 8 cache blocks (numbered 0-7). If the memory block requests are in the following order
3, 5, 2, 8, 0, 63, 9,16, 20, 17, 25, 18, 30, 24, 2, 63, 5, 82,17, 24.
Which of the following memory blocks will not be in the cache at the end of the sequence ?
(A) 3
(B) 18
(C) 20
(D) 30
Answer: (B)
Explanation: Location of memory block in cache = block % number of cache blocks
Since it is a direct mapped cache, no replacement policy is required. As we can see in the table, 18 is further replaced by 82 in the 2nd cache block whereas 3,20 and 30 are all present in the cache till the end. Therefore, Answer is B
| Memory Block | Blocks |
| 0 | 8, 0, 16, 24 |
| 1 | 9, 17, 25, 63, 17 |
| 2 | 2, 18, 2, 82 |
| 3 | 3 |
| 4 | 20 |
| 5 | 5, 5 |
| 6 | 30 |
| 7 | 63,63 |