CHAPTER 13
CHAPTER 13 CHAPTER 13
702 Chapter 13 Optical Storage Table 13.6 CLV Versus CAV Technology Quick Reference CLV (Constant Linear Velocity) CAV (Constant Angular Velocity) Speed of CD rotation: Varies with data position on CD— Constant faster on inner tracks than on outer tracks Data transfer rate: Constant Varies with data position on CD— faster on outer tracks than on inner tracks Noise level: Higher Lower CD-ROM drives have been available in speeds from 1x up to 56x and beyond. Most nonrewritable drives up to 12x were CLV; most drives from 16x and up are CAV. With CAV drives, the track data is moving past the read laser at various speeds, depending on where the data is physically located on the CD (near the inner or outer part of the track). This also means that CAV drives read the data at the edge of the disk more quickly than data near the center. This allowed for some misleading Table 13.7 CD-ROM Drive Speeds and Transfer Rates Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 Time Time Transfer Actual Minimum Advertised to Read to Read Rate CD-ROM Speed Transfer CD-ROM Speed 74-minute 80-minute (Bytes/sec) Minimum Rate if CAV (Max. if CAV) CD if CLV CD if CLV (Max. if CAV) if CAV (Bytes/sec) 1x 74.0 80.0 153,600 0.4x 61,440 2x 37.0 40.0 307,200 0.9x 138,240 4x 18.5 20.0 614,400 1.7x 261,120 6x 12.3 13.3 921,600 2.6x 399,360 8x 9.3 10.0 1,228,800 3.4x 522,240 10x 7.4 8.0 1,536,000 4.3x 660,480 12x 6.2 6.7 1,843,200 5.2x 798,720 16x 4.6 5.0 2,457,600 6.9x 1,059,840 20x 3.7 4.0 3,072,000 8.6x 1,320,960 24x 3.1 3.3 3,686,400 10.3x 1,582,080 32x 2.3 2.5 4,915,200 13.8x 2,119,680 40x 1.9 2.0 6,144,000 17.2x 2,641,920 48x 1.5 1.7 7,372,800 20.7x 3,179,520 50x 1.5 1.6 7,680,000 21.6x 3,317,760 52x 1.4 1.5 7,987,200 22.4x 3,440,640 56x 1.3 1.4 8,601,600 24.1x 3,701,760
What Is a CD-ROM? Chapter 13 703 advertising when these drives first came out. For example, a 12x CLV drive reads data at 1.84MB/sec no matter where that data is on the disc. On the other hand, a 16x CAV drive reads data at speeds up to 16x (2.46MB/sec) on the outer part of the disc, but it also reads at a much lower speed of only 6.9x (1.06MB/sec) when reading the inner part of the disc. On average, this would be only 11.5x, or about 1.76MB/sec. The average is actually overly optimistic because discs are read from the inside (slower part) out, and an average would relate only to reading completely full discs. The real-world average could be much less than that. What this all means is that the 12x CLV drive would be noticeably faster than the 16x drive, and faster than even a 20x drive! Remember that all advertised speeds on CAV drives are only the maximum transfer speed the drive can achieve, and it can achieve that only when reading the very end part of the disc. Table 13.7 contains data showing CD-ROM drive speeds along with transfer rates and other interesting data. Column 7 Column 8 Column 9 Column 10 Column 11 Column 12 Average Maximum Maximum Speed Rotational Average Transfer Linear Linear Min. if CLV Speed CD-ROM Speed Rate if CAV Speed Speed Max. if CAV Max. if if CAV (Bytes/sec) (m/sec) (mph) (rpm) CLV (rpm) 0.7x 107,520 1.3 2.9 214 497 1.5x 222,720 2.6 5.8 428 993 2.9x 437,760 5.2 11.6 856 1,986 4.3x 660,480 7.8 17.4 1,284 2,979 5.7x 875,520 10.4 23.3 1,712 3,973 7.2x 1,098,240 13.0 29.1 2,140 4,966 8.6x 1,320,960 15.6 34.9 2,568 5,959 11.5x 1,758,720 20.8 46.5 3,425 7,945 14.3x 2,196,480 26.0 58.2 4,281 9,931 17.2x 2,634,240 31.2 69.8 5,137 11,918 22.9x 3,517,440 41.6 93.1 6,849 15,890 28.6x 4,392,960 52.0 116.3 8,561 19,863 34.4x 5,276,160 62.4 139.6 10,274 23,835 35.8x 5,498,880 65.0 145.4 10,702 24,828 37.2x 5,713,920 67.6 151.2 11,130 25,821 40.1x 6,151,680 72.8 162.8 11,986 27,808
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- Page 5 and 6: What Is a CD-ROM? Chapter 13 691 7.
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- Page 9 and 10: Table 13.1 CD-ROM Technical Paramet
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- Page 29 and 30: Table 13.16 CD File System Formats
- Page 31 and 32: Figure 13.6 A diagram of basic ISO
- Page 33 and 34: DVD Chapter 13 719 video or more. T
- Page 35 and 36: DVD Chapter 13 721 The DVD disc’s
- Page 37 and 38: Table 13.17 Continued Media bit cel
- Page 39 and 40: DVD Chapter 13 725 Unlike CDs, DVDs
- Page 41 and 42: Figure 13.9 DVD disk types and cons
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702 Chapter <strong>13</strong> Optical Storage<br />
Table <strong>13</strong>.6 CLV Versus CAV Technology Quick Reference<br />
CLV (Constant Linear Velocity) CAV (Constant Angular Velocity)<br />
Speed of CD rotation: Varies with data position on CD— Constant<br />
faster on inner tracks than on outer tracks<br />
Data transfer rate: Constant Varies with data position on CD—<br />
faster on outer tracks than on inner tracks<br />
Noise level: Higher Lower<br />
CD-ROM drives have been available in speeds from 1x up to 56x and beyond. Most nonrewritable<br />
drives up to 12x were CLV; most drives from 16x and up are CAV. With CAV drives, the track data is<br />
moving past the read laser at various speeds, depending on where the data is physically located on<br />
the CD (near the inner or outer part of the track). This also means that CAV drives read the data at<br />
the edge of the disk more quickly than data near the center. This allowed for some misleading<br />
Table <strong>13</strong>.7 CD-ROM Drive Speeds and Transfer Rates<br />
Column 1 Column 2 Column 3 Column 4 Column 5 Column 6<br />
Time Time Transfer Actual Minimum<br />
Advertised to Read to Read Rate CD-ROM Speed Transfer<br />
CD-ROM Speed 74-minute 80-minute (Bytes/sec) Minimum Rate if CAV<br />
(Max. if CAV) CD if CLV CD if CLV (Max. if CAV) if CAV (Bytes/sec)<br />
1x 74.0 80.0 153,600 0.4x 61,440<br />
2x 37.0 40.0 307,200 0.9x <strong>13</strong>8,240<br />
4x 18.5 20.0 614,400 1.7x 261,120<br />
6x 12.3 <strong>13</strong>.3 921,600 2.6x 399,360<br />
8x 9.3 10.0 1,228,800 3.4x 522,240<br />
10x 7.4 8.0 1,536,000 4.3x 660,480<br />
12x 6.2 6.7 1,843,200 5.2x 798,720<br />
16x 4.6 5.0 2,457,600 6.9x 1,059,840<br />
20x 3.7 4.0 3,072,000 8.6x 1,320,960<br />
24x 3.1 3.3 3,686,400 10.3x 1,582,080<br />
32x 2.3 2.5 4,915,200 <strong>13</strong>.8x 2,119,680<br />
40x 1.9 2.0 6,144,000 17.2x 2,641,920<br />
48x 1.5 1.7 7,372,800 20.7x 3,179,520<br />
50x 1.5 1.6 7,680,000 21.6x 3,317,760<br />
52x 1.4 1.5 7,987,200 22.4x 3,440,640<br />
56x 1.3 1.4 8,601,600 24.1x 3,701,760
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