18. We have two types of machine as follows: Processor Clock Rate (MHz) MIPS rate CPU time (sec) Machine A 5 1 12 x Machine B 25 18 x Mache A requires 12 times longer than Machine B measured in CPU time. For example, a program takes 1 second in Machine B will take 12 seconds. 1) What is the relative size of the instruction count for the program running on the two machines

One subtask in the game is to roll the dice. explain why is roll the dice an abstraction.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

What are "open-loop" and "closed-loop" systems