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Wobble Frequency
Optical discs, with the exception of DVD-RAM, have their data encoded on a single spiral, or a ''groove'', which covers the surface of the disc. In the case of recordable media, this spiral contains a slight sinusoidal deviation from a perfect spiral. The period of this sine curve corresponds to the wobble frequency. The wobble frequency is commonly used as a synchronization source to achieve constant linear velocity while writing a disc, but has other uses as well depending on the type of disc. The frequencies quoted all assume that the disc is being written at the '1x' speed. The frequencies are appropriately higher for faster writing speeds. CD-R and CD-RW discs use a frequency modulated wobble of 22.05 kHz to encode information, such as the Absolute Time in Pregroove (ATIP), into the groove. DVD-R and DVD-RW have a constant wobble frequency of 140.6 kHz relying on data 'pits' beside the groove to convey information (Land pre-pit). DVD+R and DVD+RW have a constant wob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Discs
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of Compact disk#Physical details, pits and lands on a special material, often aluminum, on one of its flat surfaces. Its main uses are physical offline data distribution and long-term archival. Changes from pit to land or from land to pit correspond to a binary value of 1; while no change, regardless of whether in a land or a pit area, corresponds to a binary value of 0. Non-circular optical discs exist for fashion purposes; see shaped compact disc. Design and technology The encoding material sits atop a thicker substrate (usually polycarbonate) that makes up the bulk of the disc and forms a dust defocusing layer. The encoding pattern follows a continuous, spiral path covering the entire disc surface and extending from the innermost track to the outermost track. The data are stored on the disc with a laser or Replication ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVD-R
DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('burned') to the disc by a laser, rather than the data being 'pressed' onto the disc during manufacture, like a DVD-ROM. Pressing is used in mass production, primarily for the distribution of home video. Like CD-Rs, DVD recordable uses dye to store the data. During the burning of a single bit, the laser's intensity affects the reflective properties of the burned dye. By varying the laser intensity quickly, high density data is written in precise tracks. Since written tracks are made of darkened dye, the data side of a recordable DVD has a distinct color. Burned DVDs have a higher failure-to-read rate than pressed DVDs, due to differences in the reflective properties of dye compared to the aluminum substrate of pressed discs. Comparing recordab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compact Disc
The compact disc (CD) is a Digital media, digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in October 1982 in Japan and branded as ''Compact Disc Digital Audio, Digital Audio Compact Disc''. The format was later adapted (as CD-ROM) for general-purpose data storage. Several other formats were further derived, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video CD (VCD), Super Video CD (SVCD), Photo CD, Picture CD, Compact Disc-Interactive (CD-i) and Enhanced Music CD. Standard CDs have a diameter of and are designed to hold up to 74 minutes of uncompressed stereo digital audio or about 650 mebibyte, MiB of data. Capacity is routinely extended to 80 minutes and 700 mebibyte, MiB by arranging data more closely on the same sized disc. The Mini CD has various diameters ranging from ; t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HD DVD
HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format. HD DVD employed a blue laser with a shorter wavelength (with the exception of the 3× DVD and HD REC variants), and it stored about 3.2 times as much data per layer as its predecessor (maximum capacity: 15 GB per layer compared to 4.7 GB per layer on a DVD). The format was commercially released in 2006 and fought a protracted format war with rival Blu-ray. On February 19, 2008, Toshiba abandoned the format, announcing it would no longer manufacture HD DVD players and drives. The HD DVD Promotion Group was dissolved on March 28, 2008. The HD DVD physical disc specifications (but not the codecs) were used as the basis for the China Blue High-definition Disc (CBHD) formerly called CH-DVD. History In the lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BD-R
Blu-ray Disc Recordable (BD-R) refers to two direct to disc optical disc recording technologies that can be recorded on to a Blu-ray-based optical disc with an optical disc recorder. BD-R discs can be written to once, whereas Blu-ray Disc Recordable Erasable (BD-RE) can be erased and re-recorded multiple times. Disc capacities are 25 GB for single-layer discs, 50 GB for double-layer discs, 100 GB ("XL") for triple-layer, and 128 GB for quadruple-layer (in BD-R only). The minimum speed at which a Blu-ray Disc can be written is 36 megabits (4.5 megabytes) per second. Version , there are five versions of Blu-ray Disc Recordable Erasable (BD-RE) and four versions of Blu-ray Disc Recordable (BD-R). Each version includes three ''Parts'' (a.k.a. ''Books''): Basic Format Specifications, File System Specifications, Audio Visual Basic Specifications. Each part has sub-versions (e.g. R2 Format Specification includes ''Part 3: Audio Visual Basic Specifications Ver.3.02'', ''Part 2: File Sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVD+RW
DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('burned') to the disc by a laser, rather than the data being 'pressed' onto the disc during manufacture, like a DVD-ROM. Pressing is used in mass production, primarily for the distribution of home video. Like CD-Rs, DVD recordable uses dye to store the data. During the burning of a single bit, the laser's intensity affects the reflective properties of the burned dye. By varying the laser intensity quickly, high density data is written in precise tracks. Since written tracks are made of darkened dye, the data side of a recordable DVD has a distinct color. Burned DVDs have a higher failure-to-read rate than pressed DVDs, due to differences in the reflective properties of dye compared to the aluminum substrate of pressed discs. Comparing recordabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVD+R
The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind of digital data and has been widely used for video programs (watched using DVD players) or formerly for storing software and other computer files as well. DVDs offer significantly higher storage capacity than compact discs (CD) while having the same dimensions. A standard DVD can store up to 4.7 GB of storage, while variants can store up to a maximum of 17.08 GB. Prerecorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD. Such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs ( DVD-R and DVD+R) can be recorded once using a DVD recorder and then function as a DVD-ROM. Rewritable DVDs (DVD-RW, DVD+RW, and DVD-RAM) can be recorded and e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVD-RW
DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('burned') to the disc by a laser, rather than the data being 'pressed' onto the disc during manufacture, like a DVD-ROM. Pressing is used in mass production, primarily for the distribution of home video. Like CD-Rs, DVD recordable uses dye to store the data. During the burning of a single bit, the laser's intensity affects the reflective properties of the burned dye. By varying the laser intensity quickly, high density data is written in precise tracks. Since written tracks are made of darkened dye, the data side of a recordable DVD has a distinct color. Burned DVDs have a higher failure-to-read rate than pressed DVDs, due to differences in the reflective properties of dye compared to the aluminum substrate of pressed discs. Comparing recordab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Time In Pregroove
Absolute Time in Pregroove (ATIP) is a method of storing information on an optical medium, used on CD-R and CD-RW . ATIP information is only readable on CD-R and CD-RW drives, as read-only drives don't need the information stored on it. The information indicates if the disk is writable and information needed to correctly write to the disk. Usage ATIP is used as a method of putting data on an optical medium, specifically: * Manufacturer * Writable/Rewritable * Dye type * Spiral length in blocks * Rated speed * Audio These features are rather important to the function as it lets the drive know if it is writable. If the disc is re-writable, and the ATIP is damaged, it will not be able to write more than once. Also, it lets the drive know what the maximum write speed available for the disc is, and how much space (in blocks) the disc holds. Function Every writable disc has at least four layers: * Disc substrate – the bulk of the disc is 1.2 mm thick, and is usually injection mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DVD-RAM
DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorders and personal video recorders since 1998. In May 2019, Panasonic, the only remaining manufacturer of DVD-RAM discs, announced that it would end production of DVD-RAM media by the end of that month, citing shrinking demand as the primary motivation. Panasonic made its discs under its own brand name and also under the Verbatim brand. Cartridge types Format DVD-RAM works by means of phase change technology which was chosen instead of magneto-optical technology (an already existing rewritable solution at the time) because it doesn't require a magnetic head and therefore it represented reduced complexity and costs. Phase change technology uses laser light to heat the surface of a phase changing alloy and allows it to go from a crystalline to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280.2C1.29 RLL, computing. In Analog signal, analog frequency modulation, such as radio broadcasting, of an audio signal representing voice or music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies may represent digits, such as '0' and '1'. FSK is widely used in computer modems, such as fax modems, telephone caller ID systems, garage door openers, and other low-frequency transmissions. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD-RW
CD-RW (Compact Disc-Rewritable) is a digital media, digital optical disc data storage device, storage format introduced in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written. CD-RWs, as opposed to CDs, require specialized readers that have sensitive laser optics. Consequently, CD-RWs cannot be read in many CD readers built prior to the introduction of CD-RW. CD-ROM drives with a "MultiRead" certification are compatible. CD-RWs must be erased or blanked before reuse. Erasure methods include full blanking where the entire surface of the disc is erased and fast blanking where only metadata areas, such as PMA (CD), PMA, TOC (CD), TOC and pregap, are cleared. Fast blanking is quicker and usually sufficient to allow rewriting the disc. Full blanking removes all traces of the previous data, and is often used for confidentiality purposes. CD-RWs can sustain fewer re-writes compared to other storage media (ca. 1,000 compared up to 100,000). Ideal use is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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