What is the word that means, "using ideas to represent lower layers of detail"? and why is it so important in computer science?

Acomputer has a two-level cache. suppose that 60% of the memory references hit on the first level cache, 35% hit on the second level, and 5% miss. the access times are 5 nsec, 15 nsec, and 60 nsec, respectively, where the times for the level 2 cache and memory start counting at the moment it is known that they are needed (e.g., a level 2 cache access does not even start until the level 1 cache miss occurs). what is the average access time?

How would you categorize the software that runs on mobile devices? break down these apps into at least three basic categories and give an example of each.

In the above figure, what type of cylinder arrangement is shown in the figure above? a. l-type b. v-type c. in-line d. horizontal pls make sure its right if its rong im grounded for 3months