1. Copyright © 2004 Pearson Education, Inc.

2. Chapter 13 Disk Storage, Basic File Structures, and Hashing

3. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-3 FIGURE 13.1 (a) A single- sided disk with read/ write hardware. (b) A disk pack with read/write hardware.

4. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-4 FIGURE 13.2 Different sector organizations on disk. (a) Sectors subtending a fixed angle. (b) Sectors maintaining a uniform recording density.

5. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-5 FIGURE 13.3 Interleaved concurrency versus parallel execution.

6. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-6 FIGURE 13.4 Uses of two buffers, A and B, for reading from disk.

7. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-7 FIGURE 13.5 Three record storage formats. (a) A fixed-length record with six fields and size of 71 bytes. (b) A record with two variable-length fields and three fixed- length fields. (c) A variable-field record with three types of separator characters.

8. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-8 FIGURE 13.6 Types of record organization. (a) Unspanned. (b) Spanned.

9. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-9 FIGURE 13.7 Some blocks of an ordered (sequential) file of EMPLOYEE records with NAME as the ordering key field.

10. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-10 FIGURE 13.8 Internal hashing data structures. (a) Array of M positions for use in internal hashing. (b) Collision resolution by chaining records.

11. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-11 FIGURE 13.9 Matching bucket numbers to disk block addresses.

12. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-12 FIGURE 13.10 Handling overflow for buckets by chaining.

13. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-13 FIGURE 13.11 Structure of the extendible hashing scheme.

14. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-14 FIGURE 13.12 Data striping. File A is striped across four disks.

15. Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition Copyright © 2004 Pearson Education, Inc. Slide 13-15 FIGURE 13.13 Multiple levels of RAID. From Chen, Lee, Gibson, Katz, and Patterson (1994), ACM Computing Survey, Vol. 26, No. 2 (June 1994). Reprinted with permission.