Chapter 5 Optical Storage Technology. Categorizing Storage Devices History of CD/DVD player Optical Storage Devices DVD-ROM and DVD Formats

Transcription

1 Chapter 5 Optical Storage Technology Categorizing Storage Devices History of CD/DVD player Optical Storage Devices DVD-ROM and DVD Formats

2 Categorizing Storage Devices Storage devices hold data, even when the computer is turned off. The physical material that actually holds data is called a storage medium. The hardware that writes data to or reads data from a storage medium is called a storage device. A floppy disk drive is a storage device. The two primary storage technologies are magnetic and optical.

3 History of the CD/DVD player First working CD player developed by Philips Philips and Sony developed CD standard 12cm disk, 74 minutes on a single spiral First CD players sold CD-ROM introduced not popular at first. More powerful PCs lead to demand for multimedia, image processing and larger applications. Growth in sales brings prices down s - CD-R and CD-RW introduced big success DVD introduced DVD becomes mainstream 3.9GB capacity allows disk to hold entire movie. DVD drives are standard on PCs today. 4

4 Products

5 Different Formats CD-DA (store digitized music ) CD-G (Graphics) (store graphics and music) CD-V (store analog television programs) CD-ROM (store digitized images and voices) CD-I (Interactive) (store digitized images, voices and animations) CD-I FMV(Full Motion Video) (store digitized films and TV programs) Video CD (MPEG1) DVD (MPEG2)

6 Optical Storage Devices How Optical Storage Works An optical disk is a high-capacity storage medium. An optical drive uses reflected light to read data. To store data, the disk's metal surface is covered with tiny pits and flat spots (lands), which cause light to be reflected differently. When an optical drive shines light into a pit, the light can not be reflected back. This represents a bit value of 0 (off). A land reflects light back to its source, representing a bit value of 1 (on).

7 Optical Storage Devices How Optical Storage Works

8 CD-ROM In PCs, the most commonly used optical storage technology is called Compact Disk Read-Only Memory (CD-ROM). A standard CD-ROM disk can store up to 650 MB of data, or about 70 minutes of audio. Once data is written to a standard CD-ROM disk, the data cannot be altered or overwritten..

9 The Structure of CD-ROM Diameter:120mm Depth:1.2mm

10 CD Playback Pits are read by laser and converted to electrical signals

11 Sequence of Operations in A CDROM Drive 1. Laser Diode - Emits a Laser Beam 2. Prisms - The laser beam is refined and Directed to a Mirror 3. Mirror - Reflects the Laser beam onto the Read Head 4. Read Head - Focuses the Laser beam onto the correct Physical Location on the Active Surface

12 Sequence of Operations in A CDROM Drive 5. Active Surface - Reflects the Laser Beam Back onto the Read Head 6. Laser Beam Passes Through the Read Head onto the Mirror 7. Mirror Redirects the Laser onto a new set of Prisms 8. The Prisms Guide the Laser to a Photo Diode 9. The Photo Diode Recognizes the Character

13 CD-ROM Speeds and Uses How fast the CD-ROM disc spins determines its speed Early CD-ROM drives were called single speed, and read data at a rate of 150 KBps. (Hard disks transfer data at rates of 5 15 MBps). CD-ROM drives now can transfer data at speeds of at least to 7800 KBps. CD-ROM is typically used to store software programs. CDs can store audio and video data, as well as text and program instructions.

14 CD-ROM CD-ROMs contain tracks which may be either data, audio or video tracks CD-ROMs have sectors Data track on a CD is one long, continuous spiral (b) CLV(constant linear velocity) & CAV Data track on a magnetic disk is concentric circles (a) CAV(constant angular velocity)

15 CD 光盘光道结构 CD 盘的光道结构与磁盘磁道的结构比较 CD 光盘 磁盘 记录道 螺旋形 同心环 磁道数目 很多 只有一条, 长约 5 km 盘片转动速度 CLV( 恒定线速度 ) CAV( 恒定角速度 ) 记录密度 里外记录区的密度相同 里外记录区的密度不同 光道形状

16 Sector Structure in CD-ROM CD-ROMs contain 333,000 sectors/blocks Single speed is 75 sectors per second. Each block/sector contains 2352 bytes: 12 bytes to mark the start of the block 4 bytes for a header 2048 bytes of user data 4 bytes for error detection 8 unused bytes 276 bytes for error correction

17 CD-ROM Capacity Calculations Capacity is calculated as follows: 333,000 blocks * 2048 bytes per block = 681,984,000 bytes Data rate is: 681,984, Mbytes 2048 bytes * 75 blocks per second 150 Kbytes/sec (1x) 40x 6000 Kbytes/sec or 6 Mbytes/sec

18 Other Optical Storage Devices CD-RW Drives A CD-RW means Compact Disc-ReWritable. CD-RWs allow you to write, and re-write, data on CD-RW discs. CD-R discs allow you to write BUT NOT rewrite data to the disk.

19 Other Optical Storage Devices CD-RW Applications Store and Transfer Data (Up to 700 MB) Record Music (Up to 74 minutes) Play Music CDs Play Multimedia CDs

20 Other Optical Storage Devices CD-RW Speed CD-RW drives operate at several speeds. Example: Write 12X Rewrite 10X refers to how fast a CD-RW can record data on a CD-R disc refers to how fast it can write to a CD-RW disc Read 32X refers to how fast data transfers from a disc to the computer

21 DVD-ROM A variation of CD-ROM is called Digital Video Disk Read-Only Memory (DVD-ROM), and is being used in place of CD-ROM in many newer PCs. Standard DVD disks store up to 4.7 GB of data enough to store an entire movie. Dual-layer DVD disks can store up to 17 GB. DVD disks can store so much data because both sides of the disk are used, along with sophisticated data compression technologies.

22 DVD-ROM More capacity: 133 minutes of high resolution MPEG-2 video Smaller pit size, tighter track spacing, multiple layers Needs very precise reading mechanism Uses MPEG-2 video compression; requires MPEG-2 controller to decode compressed data Audio is stored in Dolby AC-3 compression

23 DVD Formats Different formats Single-sided, single-layer 4.7 GB DVD5 Double-sided, single-layer 9.4 GB DVD10 Storage for approximately two feature length films. Single-sided, double-layer 8.5 GB DVD9 Effectively two disks bonded together Upper disk has partially transmissive surface Lower disk has fully reflective surface Laser can focus on either surface Double-sided, double-layer 17 GB DVD18

24 DVD Formats

25 DVD Features Over 2 hours of high-quality digital video (a double-sided, dual-layer disc can hold about 8 hours of high-quality video, or 30 hours of VHS quality video). Support for widescreen movies on standard or widescreen TVs (4:3 and 16:9 aspect ratios). Up to 8 tracks of digital audio (for multiple languages, commentaries, etc.), each with as many as 8 channels. Up to 32 subtitle/karaoke tracks.

26 DVD Features On-screen menus and simple interactive features (for games, etc.). Multilingual identifying text for title name, album name, song name, etc. Instant search to title, chapter, music track, and timecode. Not susceptible to magnetic fields. Resistant to heat. Language choice (for automatic selection of video scenes, audio tracks, subtitle tracks, and menus).* Random play and repeat play. Recognition and output of DTS Digital Surround audio tracks. Playback of audio CDs.

27 Next Generation DVD Blue laser (450nm) instead of red (650nm) Blue-Ray Sony, Hitachi, LG, Matsushita, Philips, Pioneer, Samsung, Sharp and Thomson DVD-HD Toshiba, NEC, Warner, Paramount, Universal

28 Blu-Ray Blu-ray (BD) is a next-generation optical disc format. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The companies that have jointly established the BD specifications are Hitachi, Ltd LG Electronics Matsushitha Electrical Industrial Co. Ltd Mitsubishi Electric Corporarion

29 Blu-Ray Pioneer Corporation Samsung Electronics Co. Ltd Sony Thomson Royal Phillips Electronics Sharp Corporation The name Blu-ray is derived from the blue-violet laser it uses to read and write to the disc. The e was intentionally left out of the name due to trademark restrictions

30 Capacity The Blu-ray disc enables the recording, rewriting and playback of HD video up to 27 GB of data on a single sided single layer. It is enough to put 2.5 hours of HDTV recording on it. It also can record over 13 hours of standard TV broadcasting

31 Robustness of Disc Stronger resistance to scratches and fingerprints The protective layer is hard enough to prevent accidental abrasions and allows fingerprints to be removed by wiping the disc with a tissue. Compatible The BD drives are designed to be backward compatible, i.e. CDs and DVDs work equally well with the BD drives.

32 Principal BD Specifications Capacity Wave length of the laser Numerical Aperture of the objective lens Data transfer rate Thickness of the disc Diameter of the center hole Recording method Data track Visual data GB (single layer) 405nm Mbps 1.2mm 15mm Phase change Groove recording MPEG-2 video

33 Comparison of CD,DVD and BD specification Parameter CD DVD BD disk diameter 120 mm 120 mm 120 mm Disk thickness 1.2 mm 1.2 mm 1.2 mm Laser wavelength 780 nm 650 nm 450 nm Numerical aperture Minimum pit length 0.83 um 0.4 um um Data rate 1.2 Mb/sec 11 Mb/sec 36 Mb/sec Number of sides one one or two Number of data layers one One or two Data capacity ~680 MB 4.7 GB (1L) 27 GB 8.5 GB (2L) 17 GB (2L/2S)

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36 传统 DVD 的生产方法是 : 注塑成型两个 0.6 毫米的盘片, 记录层位于两个盘片之间 蓝光光盘则只需要在一个 1.1 毫米的盘片上执行注塑成型工艺, 从而减少成本 目前 DVD 的传输速率 10 Mbps( 每秒兆位数 ), 蓝光光盘的数据传输速率更高, 为 36Mbps 蓝光光盘可以在不到两个小时的时间内录制 25G B 的内容

37 Blu-ray Disc Applications High definition television recording High definition video distribution High definition camcorder archiving Mass data storage

38 High definition television recording The Blu-ray Disc format offers consumers the ability to record their High Definition television broadcasts in their original quality for the first time, preserving the pure picture and audio level as offered by the broadcaster. Next level in home entertainment, offering an unsurpassed user experience since Blu-ray Disc format incorporates the strongest copy protection algorithms of any format or proposal to date, the format allows for recording of digital broadcasts while meeting the content protection demands of the broadcast industry.

39 High Definition Video Distribution Blu-ray Disc format can store High Definition video in the highest possible quality, without need to compromise on picture quality. Depending on the encoding method, there is room for more than seven hours of the highest HD quality video. There is even room for additional content such as special features and other bonus material to accompany the High Definition movie. The Blu-ray Disc movie format greatly expands on traditional DVD capabilities, by incorporating many new interactive features allowing content providers to offer an even more incredible experience to consumers.

40 Mass Data Storage The growing number of broadband connections allowing consumers to download vast amounts of data

41 Regional Coding Different countries have different region number. 1. U.S., Canada, U.S. Territories 2. Japan, Europe, South Africa, and Middle East (including Egypt) 3. Southeast Asia and East Asia (including Hong Kong) 4. Australia, New Zealand, Pacific Islands, Central America, Mexico, South America, and the Caribbean 5. Eastern Europe (Former Soviet Union), Indian subcontinent, Africa, North Korea, and Mongolia 6. China 7. Reserved 8. Special international venues (airplanes, cruise ships, etc.)