20 pts dbase a pet salon has the following very

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Unformatted text preview: the process control block iv. Pre ­emptive scheduling technique similar to round ­robin d. (3 pts) If the following jobs are scheduled in the order shown in round ­robin fashion, what is the average completion time? Parenthesized numbers show the time required for each job in milliseconds. Assume each time slice is 10 ms. Job 1 (10); Job 2 (20); Job 3 (30); Job 4 (40). 12. 10 pts [File sys/directories] Give one ­sentence answers for a. through d. a. What is the difference between a relative and an absolute path? b. What is the “Scan” method for disk scheduling? c. What is a ”file extension” and why is it important? d. What is meant by the “root directory”? e. The structure of a file system is naturally modeled as (circle one) i. paged memory ii. a database iii. a graph iv. a tree v. an array 6 13. 20 pts [Dbase] A pet salon has the following very simple database to keep track of the pets and their owners. Customers TABLE Pets TABLE cust_id 1 John 2 name Mary owner_id petname 1 Fido 2 Fluffy 2 Bowser For parts a. through e., draw the table which is the result of the query: a. 3pts SELECT petname FROM Pets WHERE owner_id = 2 b. 3pts SELECT * FROM Pets WHERE petname LIKE “%o%” c. 3pts SELECT petname FROM Pets WHERE petname LIKE “B_” d. 3pts SELECT name, petname FROM Customers, Pets WHERE cust_id = owner_id 7 e. 3pts SELECT * FROM Customers, Pets f. 1 pt True or False? An advantage of using multiple tables in a database is to allow for the replication of data so that data won’t be lost. g. 4 pts Write a query that returns the names of the owners who have pets whose names begin with “F”. (The query should work regardless of what additional recor...
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