database management systems -- 2

1 Questions

You are required to answer the following questions. Please denote your assumptions if any information is

not given explicitly. Note that your assumption must be reasonable.

Q1. (40 points) Consider a disk with the following properties:

 There are 8 platters providing 16 surfaces.

 There are 210 = 1024 tracks per surface.

 There are (on average) 28 = 256 sectors per track.

 There are 29 = 512 bytes per sector.

 Assume 10% of each track is used as overhead.

Please answer the following questions:

(a) (20 points) What is the maximum amount of this disk that can be used to store actual data?

(b) (20 points) Suppose that the last I=O request accessed cylinder 1000 (Cylinders are numbered

sequentially: 1, 2,


, 1024 from the out most track to the inner most track). What is the

expected (average) number of cylinders that will be traveled due to the very next I=O request to

this disk?

Q2. (60 points) Consider the following relation describing employees in a company Employee(eno: integer,

name: char(20), phone: integer, age: integer, salary: real). Giving page size with 4096 bytes and 20

bytes reserved for page header.

(a) (30 points) Consider dierent page formats, calculate how many records can be stored per page.

You need to consider:

 (15 points) Each page has a BITMAP to manage the records (Unpacked BITMAP page) .

 (15 points) Each page has a directory of slots (hrecord oset, record lengthi) to manage the

records (Slotted page format).

(b) (15 points) Please draw the page structure after inserting the following three records if you use

Slotted page format.

 E1, bob, 5711234, 23, 50000

 E2, Tom, 5711335, 33, 100000

 E3, Jerry, 5712236, 25, 70000

(15 points) Then what does the page look like after deleting record E2?

Pemrograman Database Matematika

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