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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 do not 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 m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD-R
CD-R (Compact disc-recordable) is a digital media, digital optical disc data storage device, storage format. A CD-R disc is a compact disc that can only be Write once read many, written once and read arbitrarily many times. CD-R discs (CD-Rs) are readable by most CD readers manufactured prior to the introduction of CD-R, unlike CD-RW discs. History Originally named CD Write once read many, Write-Once (WO), the CD-R specification was first published in 1988 by Philips and Sony in the Rainbow Books, Orange Book, which consists of several parts that provide details of the CD-WO, CD-MO (Magneto-Optic), and later CD-RW (Re Writable). The latest editions have abandoned the use of the term ''CD-WO'' in favor of ''CD-R'', while ''CD-MO'' was rarely used. Written CD-Rs and CD-RWs are, in the aspect of low-level encoding and data format, fully compatible with the audio CD (''Red Book'' CD-DA) and data CD (''Yellow Book'' CD-ROM) standards. The Yellow Book standard for CD-ROM only speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate ester, carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, toughness, tough materials, and some grades are optically transparent. They are easily worked, injection molding, molded, and thermoforming, thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code, resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Structure Carbonate esters have planar OC(OC)2 cores, which confer rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Polycarbonates received their name because they are polymers containing carbonate ester, carbonate groups (−O−( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. The photons of ultraviolet have greater energy than those of visible light, from about 3.1 to 12 electron volts, around the minimum energy required to ionize atoms. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack sufficient energy, it can induce chemical reactions and cause many substances to glow or fluoresce. Many practical applications, including chemical and biological effects, are derived from the way that UV radiation can interact with organic molecules. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Media Identification Code
The Media Identification Code (MID) is used on DVD-R, DVD+R and DVD-RAM discs to identify the manufacturer and to assist the DVD burner to select the best write strategy for the inserted media. The technology is inherited from the ATIP code used on CD-R discs. If the DVD burner recognizes the discs it means that the disc has been tested by the drive manufacturer to achieve the best possible burn using an optimal write strategy. The strategy is stored in the firmware. Writing to a disc with no MID code or a code that is not recognized can result in inaccurate recording and data read-back problems. Displaying the MID The following programs can be used to display the contents of the MID With Windows * instalDVDInfoProby Nic Wilson (full 14-day trial available without any adverts) * instalDVDIdentifierby Kris Schoofs (freeware) With Linux Ubuntu and other Linux systems have dvd+rw-tools installed by default, which provides a command to display the media data: $ dvd+rw-m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compact Disc Subcode
Subcode or subchannel data (called ''control bytes'' in the CD-ROM specification) is data contained in a compact disc (CD) in addition to digital audio or user data, which is used for control and playback of the CD. The original specification was defined in the Red Book standard for Compact Disc Digital Audio, though further specifications have extended their use (including the CD-ROM, CD Text and CD+G specifications). Structure Subchannel data is multiplexed with the digital audio or user digital data. The data in a CD are arranged in frames. A frame comprises 33 bytes, of which 24 bytes are audio or user data, eight bytes are error correction (CIRC-generated), and one byte is for subcode. Frames are arranged in sectors, which contain 98 frames each. The subcode bytes of the first two frames of a sector are used as two synchronization words. The subcode bytes of the remaining 96 frames of a sector are split into eight 96-bit long subcode channels (also called subchannels or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
