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EET 450 - Advance Digital. Chapter 12 CD - CDR - DVD. Compact Disk Technology. Information stored on a reflective surface, read with a laser beam. 74 minutes or 640 Mb of data storage Current 80 min/700 Mb CD-ROM is a read only version.
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EET 450 - Advance Digital Chapter 12 CD - CDR - DVD
Compact Disk Technology • Information stored on a reflective surface, read with a laser beam. • 74 minutes or 640 Mb of data storage • Current 80 min/700 Mb • CD-ROM is a read only version. • Data is recorded at manufacture using a printing-style operation
Transfer rates have been increasing • See Table for speeds • A more important measure is access time. • Massive (relatively) mechanism means slow response to move the read head into position to read information.
CD-R - Recordable media • Same storage capacity, but media uses an organic dye • Some makers now featuring 700Mb (80min) • The dye reflectivity is changed with a low power laser. • Storage is a WORM variety
CD-R Media Color • Reflective layer/Die Layer • Gold-gold – Phthalocyanine dye • Less tolerance for power variations • Gold-green – Cyanine dye • More forgiving • 10 yr life span • Silver-blue – Azo dye • Similar to green, but rated to 100 years.
CD-RW - Re-writable CD • Uses a phase-change technology • Same storage capacity as CD • active layer of CD-RW is Ag-In-Sb-Te • Silver - indium - antimony - tellurium • polycrystalline structure is reflective • High power laser heats to 500-700 degrees
This solidifies in a non-reflective state • To erase, a lower power laser heats to 200 degrees, which solidifies in the original reflective state.
CD-ROM Disc & Drive Formats • Red Book • Digital Audio CDs (CDDA) • Yellow Book • Computer CDs • Mode 1: ISO 9660 • Level 1: PC, Apple, UNIX, DVI • Level 2: CDTV
CD-ROM Disc & Drive Formats • White Book • Video CD • MPEG-1, MPEG-2 • Orange Book • Writeable CDs – CDR
Green Book • Combination of Red and Yellow Books • CD-I • CD + (Enhanced CD) • Combines Music and computer Data on 1 CD
Data Standard: ISO 9660 • High Sierra Format • CD-CA (digital Audio) • CD-ROM XA – extended architecture • Multi-session CDs
DVD • Digital Versatile Disk • initial capacity 4.7 G - 135 minutes of video with three audio and four sub-title channels. • 8.5 G dual layer disks - use a semi reflective top layer. • double sided • 9.4G single layer • 17G double layer
Additional capacity from • smaller pit length • reduced track pitch • larger data area on disk • More efficient modulation • More efficient error correction code • less sector overhead
Short wave-length laser reads • fast transfer rate - ~ 9x by CD-Rom standards • interface - standard IDE/ATA or SCSI
Recordable DVD • Two standards • DVD-R • WORM type • DVD-RAM • re-writable like CD-RW
Recordable DVD Standards • DVD-RAM – 2.6 G/side • Not compatible w/ DVD ROM $25/disk • DVD-R – 4.7G (1999 version) • Almost all can read this format $40/disk • DVD-RW – 4.7G • Almost all can read this format $40/disk • DVD+RW – 2.8G/side • A few current from Sony or Phillips $30/disk
References • http://www.toshiba.com/taecdpd/products/docs/dvdramwhitepaper.shtml • Mueller, S., Upgrading and Maintaining PC’s 12e, 2000, Que Corp.