In this problem, you have to calculate the number of disk accesses required in the worst case for different index organizations. The data base keeps track of different pieces of information for a student: name (20 bytes), idnumber (20 byes), gpa (15 bytes) and address (100 bytes). There are four hundred thousand students (it is a large university!). Each block can store 1500 bytes of information. A block pointer requires 12 bytes. The data file is sorted by the primary key, the student name. The idnumber is a secondary key.

How many disk accesses are required if:

access is through student name and there is a 2-level primary index on student name in which the second level of the index is in memory, while the first level of the index is on disk. This is somewhat different from the way the Figure 17.6 index is organized in the sense that we have only 2 levels; the second level is already in RAM, and the first level is on the disk.