Copyright © 2004 Pearson Education, Inc.
Chapter 13
Disk Storage, Basic File
Structures, and Hashing
Copyright © 2004 Pearson Education, Inc.
FIGURE 13.1
(a) A singlesided disk with
read/ write
hardware.
(b) A disk pack
with read/write
hardware.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-3
FIGURE 13.2
Different sector organizations on disk. (a) Sectors
subtending a fixed angle. (b) Sectors maintaining a
uniform recording density.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-4
FIGURE 13.3
Interleaved concurrency versus parallel execution.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-5
FIGURE 13.4
Uses of two buffers, A and B, for reading from disk.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-6
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 fixedlength fields. (c) A variable-field record with three types of separator characters.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
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FIGURE 13.6
Types of record organization. (a) Unspanned. (b)
Spanned.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-8
FIGURE 13.7
Some blocks of an
ordered (sequential)
file of EMPLOYEE
records with NAME as
the ordering key field.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-9
FIGURE 13.8
Internal hashing
data structures.
(a) Array of M positions
for use in internal
hashing. (b) Collision
resolution by chaining
records.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-10
FIGURE 13.9
Matching bucket numbers to disk block addresses.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-11
FIGURE 13.10
Handling overflow for buckets by chaining.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-12
FIGURE 13.11
Structure of the
extendible hashing
scheme.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-13
FIGURE 13.12
Data striping. File A is striped across four disks.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-14
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.
Elmasri and Navathe, Fundamentals of Database Systems, Fourth Edition
Copyright © 2004 Pearson Education, Inc.
Slide 13-15