.: Definitions :.
These definitions include information taken from several CD Glossaries found on the Internet. They are the words that cause the most confusion in the CD Duplicating industry. The IDDA offer these suggested definitions as a guide to further discussion, so that worldwide standards can be agreed and then encouraged. Suggested definitions may be followed by technical information to assist in further discussion. Please email any comments to info@discdupe.org, while IDDA members can post comments directly to the Discussion page.
Business Card CDs and Mini CDs
Business Card CDs are CDs the size of a Credit card or Business card; which play in any normal CD player; and weigh only around 10 gms. They are big in impact in a small package, and they are today's message on tomorrow's media. Mini CDs, called CD singles, 8cm discs, baby discs etc. are 8 cm discs instead of the standard 12 cm.
There are 2 basic shapes of Business card CDs:
- CDs that are oblong with pins or molded rings that hold the disc in position by running within the inner 8cm tray of the CD player, called eCards, Business Card discs, and
- CDs that are rounded to an 8cm diameter that fit into the inner 8 cm tray, sometimes called hockey rink shaped card discs or rounded card discs.
Comments:
Unfortunately Business Card CDs and Mini CDs and DVDs have lost a bit of their novelty value, and distribution of the product has been threatened by a patent application in the USA, which has been challenged by duplicators and replicators.
CD-R is an acronym Compact Disc-Recordable. This term is used to describe the technology of recordable CD as well as the equipment; software; media and technology, which is used to make recordable discs. The reduction of prices for this hardware and software and their ease of use have helped the growth of CD-ROM production in-house and by disc duplicating services.
CD-R [Disc] is a type of media used in recordable CD systems, that allows you to record digital information using a special recorder (CD Recorder) together with pre mastering software with a computer or even a stand-alone recording system that includes these elements in one unit.
CD-Recordable technology allows production of CD-ROMs on the desktop ('one-offs'). It usually requires a PC, (there are also stand-alone systems) a CD-R recorder or drive, appropriate software, and 'recordable' media. The 'one-off' disc is very different from the mass reproduced or 'hot-pressed' CDs. It is sold pre-grooved in 63, 74, 80, 90 and 100-minute capacities of 120mm diameter, as well as in different shapes, with a sensitive chemical recording layer; of aluminum or gold reflective material. Once recorded the CD-R disc (one-off) performs in the same way as the mass-reproduced CDs.
These discs are made of a polycarbonate substrate, a layer of organic dye, a metalized reflective layer and a protective lacquer coating. Some discs also have an additional protective coating over the metalized layer; and some discs have a printable surface silk-screened on them.
Comments:
CD-R or CDR - CD-R is the correct abbreviation as it is taken from CD-Recordable. The use of “CDR” should be discouraged.
CD-R Technical Description
The blank disc is made of a bottom layer of polycarbonate with a preformed track spiral, which the recording laser follows when inscribing information onto the disc. A translucent layer of recordable material is laid on top of the polycarbonate; then a reflective layer - gold or silver colored. Mitsubishi were probably the first to introduce the silver disc. On top, there is a thin layer of lacquer and sometimes a printed label.
In manufacturing CD-R media; instead of pits and lands; a continuous spiral is pressed into the substrate by injection molding from a stamper as a guide to the recorder's laser. So all Compact Discs are created by injection molding by replication, while stamped discs have the digital information molded into the disc during manufacture, and CD-R are like blank pages ready to have the digital information added by recorder. Kodak also has a 'hybrid' disc that contains both stamped data and a recordable track.
The data layer of CD-R discs is made from either cyanine or phthalocyanine dye, which is melted during the recording process. Where the dye is melted; it becomes opaque or refractive, scattering the reading laser beam so it is not reflected back into the reader's sensors. The difference between reflected and non-reflected light is interpreted by the player as a binary signal.
In a "pressed" or mass-replicated CD, the bumps and grooves that represent the binary data on a disc's substrate are pressed into it during manufacture. CD-R discs do not have true pits and lands; but the unmelted; clear areas and melted; opaque places in the dye layer fulfill the same function as pits and lands on a pressed disc.
The standard recordable disc CD-R is "write-once"- data written to it cannot be erased, although it is possible to add data in a later session as Multisession. For erasable/rewritable discs see CD-RW.
The Orange Book Recordable Compact Disc Standard was developed by Philips and Sony, was published by Philips in 1990, reportedly in a binder with Orange Covers. The Orange Book defined two new 12cm CD products: the Magneto-Optical and the Write-Once. Part 2; Write-Once (CD-WO); defines tracks that can be written to; but not erased and rewritten - in the tradition of WORM (write-once read-many) discs. A Write-Once drive records appropriate 12cm CDs - which involve special recording layers; pregrooved tracks and; generally a gold reflective layer. The initial tracks include a Program Calibration Area; are followed by a Lead-In area (where the Table of Contents will be written); and by the Program Area - for the user data. The recording session is finished with the Lead Out. A CD-WO 'Hybrid' disc involves an area where Read-Only files can be placed; and the rest of the disc is the W-O area. Later; Part 3 was released; which covers Rewritable (Phase Change) products. Part 1; Magneto-Optical (CD-MO); defines tracks that can be erased and rewritten - reason why this format is more appropriately known as Rewritable. M-O drives implement magneto- optical recording technology on 12cm CDs that are rated to allow millions of rewrites. These drives are however slower than other optical drives; because they use two heads - one to erase and the other to write; in a double-pass process. Some CD-MO products include a small premastered Read-Only area that usually contains system and other information - but which can also be read by a regular CD-ROM drive. The remainder space is the Recordable User Area; and the user can reuse this area at will. Part 3 defines Rewritable (CD-RW). Some brands designate it as Rewritable PD (for Phase Change). Developed by Philips and Sony (Oct 96); these specifications implement Phase Change technology and the Universal Disc Format (UDF) promoted by OSTA; to produce a CD that can be rewritten in one pass. Currently CD-RW cannot be read by most CD-ROM and CD-R drives because CD-RW media has much lower coefficients of reflectivity (15-25 compared to 65- 70%). But; while drives with multiple heads are considered one solution; the industry is working towards a 'single-head multiread drive.' Nevertheless; CD-RW phase change drives has almost replaced the CD-MO drives; and the optical 5.25in products as well.
CD-ROM - The Compact Disc-Read Only Memory is a standard for compact disc to be used as a digital memory medium for personal computers, a version of the compact disc for computer data, multimedia and games applications, instead of digital audio, is the standard 12cm CD formatted according to ISO 9660. Although the physical characteristics and track structure of a CD-ROM are the same as that of CD-Audio, a CD-ROM is used to store computer data, text and graphics. It also involves additional error detection and correction as specified in the Yellow Book. The logical volume and file structure of CD-ROM; specified in the ISO 9660 allows it to be used in the computer arena. Therefore, a CD with computer data that is not structured according to the ISO 9660 such as a 80 minute discs is not a standard CD-ROM. The music CD player cannot play CD-ROM discs; but CD-ROM drive can play music discs.
CD-ROMs can contain up to 650MB of data and although the specification does not include them, most CD-R discs are now 700MB, (though they often contain a lot less). CD-ROMs have become a favorite medium for installing programs; the term CD-ROM refers to the technology or the discs, but not to the hardware that plays the discs, which is a CD-ROM drive.
Comments:
Is a CD-ROM only for data and multimedia, or can we use CD-ROM to mean a stamped disc as against a duplicated disc? Many organizations have adopted CD-ROM to mean a replicated disc.
CD/DVD Duplication and CD/DVD Replication
Duplication -The reproduction of media. Generally refers to producing discs in smaller quantities, as opposed to large-scale replication. As the cost of media has dropped, as patents expired as production techniques improved, and as demand increased, blank CD and DVD media has become cheap enough to compete with replicated media cost for longer runs.
Replication - The reproduction of media such as optical discs by stamping (contrast with duplication).
Injection Molding - This is a common industrial process to produce plastic products of all shapes.
A manufacturing method where molten material is forced into a mold; usually under high pressure; and then cooled so the material takes on the shape of the mirror image of the mold. The injection molding machines, fitted with appropriates tampers; stamp or press the mold.
A process for replication of CDs wherein molten plastic is injected into the cavity of a mold under pressure; cooled and removed as a solid; clear plastic disc. The data information is transferred to the plastic in this process from the "stamper."
The mastering and replication plants require costly equipment and highly clean environments.
Manufacturing - The process of creating the physical discs from a master; consisting of creating the glass master; making stampers; molding the polycarbonate discs; electroplating the discs; printing the labels; and packaging the discs for the customer.
Quality - There is currently no proven or known difference in the quality and longevity of Duplicated media as compared to Replicated media. There are good and bad qualities in both technologies. Originally some early CD players and early DVD players would not play duplicated media, but most of these early machines would have been replaced by 2005.
Comments:
Several replicators use the word "duplication" to describe the replication process. The pocket Oxford dictionary defines duplicate as a double, exactly like the thing existing, or to make exact copy of, while duplicator is an apparatus for making multiple copies of typed or handwritten documents. Replicate itself does not appear, but a replica is a duplicate made by original artist, an exact copy, and facsimile. It therefore would appear that replicate is a word created by the industry to mean stamped discs, while a duplicate is descended from the duplication of documents.
On this premise the use of the word duplicate to include pressed discs is incorrect.
Mastering - In CD-ROM; the final recording of the desired CD-ROM image to be used as a source for mastering; this may be on tape; magnetic disc; optical disc (M-O or W-O); etc.
Technically mastering this refers to the process of creating a glass master from which compact discs is reproduced in quantity, or the process of replicating optical discs by injecting liquid plastic into a mold containing a master. Often used inaccurately to refer to premastering.
The process of encoding input data; created during premastering to the compact disc standards and recording this information as a series of pits in a light-sensitive layer on a glass substrate.
Mastering is the process of creating a stamper or set of stampers to be used in the injection molding stage of manufacturing compact discs. During this process a digital signal from a computer is used to guide a laser beam which etches a pattern of "pits and lands" (in the case of CDs) or a continuous groove (for CD-Rs) onto a highly polished glass disc coated with photoresist. This "glass master" is then cured (developed) with ultraviolet light and rinsed off; and a metal (nickel or silver) mold is electroformed on top of it. This mold is removed and then electroplated with a nickel alloy to create one or more stampers to be used in the injection molding machine to press the data into the polycarbonate substrate of CDs; or the guiding groove into the substrate of CD-Rs. media or "blanks".
In desktop recordable CD systems; mastering is done together with premastering by the desktop CD recorder; and the term is generally used to mean "recording."
Comments:
How do we differentiate the Mastering that is just "making a master" from the Mastering that refers to the Equalization, Compression and other manipulation of audio mixes?
Under the Orange Book standard for recordable CD; hybrid means a recordable disc on which one or more sessions are already recorded; but the disc is not closed, leaving space open for future recording.
However; the term "hybrid" often refer to a disc containing both DOS/Windows and Macintosh software; which on a DOS/Windows platform is seen as a normal ISO9660 disc; while on a Mac it appears as an HFS disc.
"Hybrid" is also used to describe a disc that supplements a web site.
Customization in the CD industry usually means each disc is different, either in data content or labeling. To some it means any short run duplication, but we suggest that this is not a recommended definition.