Capital A to Z, digits 0 to 9, and the following symbols: (space) ! " % & ()=*+,-./:;?_
The time it takes to retrieve a piece of information. With hard disks or compact discs, maximum access time is measured as the time it takes to move from one end of the disc to the other, find a piece of information, and transfer that information to RAM.
A tape recorded with a file structure and tape label system which defines the Volume name and file header for the information contained in the tape, according to ANSI (American National Standards Institute) specification X3.27- 19778. Most disc manufacturers prefer ANSI-labeled tapes.
A tape recorded with a file structure, but without the ANSI tape labels.
Advanced SCSI Programmer's Interface. Set of software primitives and data structures which allow software using the ASPI interface to be SCSI host adapter- independent.
An amount of memory which temporarily stores data to help compensate for differences in the transfer rate of data from one device to another.
A portion of RAM used for temporary storage of data which must be accessed very quickly. In CD-ROM applications, the cache is typically used to store directory files.
The plastic and metal carrier into which a CD must be inserted before it is loaded into some CD-ROM drives or CD recorders.
Compact Disc-Digital Audio. Jointly developed by Philips and Sony and launched in October 1982, CD-DA was the first incarnation of the compact disc, used to digitally record and play back music at unprecedented quality. The standard under which CD-DA discs are recorded is known as the Red Book.
A compact disc format designed to allow interactive multimedia applications to be played through a computer/disc player attached to a television. Especially good for real-time animation, video, and sound. The CD-I standard is called the Green Book.
A set of specifications defining a way of recording CD-I information on a CD- ROM XA disc. Used for Photo CD.
Compact disc-recordable.
Compact Disc-Read Only Memory. A standard for compact disc to be used as a digital memory medium for personal computers. The specifications for CD- ROM were first defined in the Yellow Book.
A peripheral device attached to a computer which allows it to read/play a CD-ROM disc. All CD-ROM players can also play back audio CDs, but you need external headphones or speakers to hear them.
"XA" stands for Extended Architecture. CD-ROM XA is an extension of the Yellow Book standard, generally consistent with the ISO 9660 logical format but designed to add better audio and video capabilities (taken from the CD-I standard) so that CD-ROM can more easily be used for multimedia applications. CD-ROM XA is also the physical format for Photo CD discs.
Compact Disc-Write Once. Recordable compact disc.
Commodore's entry into the consumer multimedia market, a compact disc player/computer that connects to a home television screen. Uses a proprietary disc format based on the ISO 9660 standard.
To "close" a recordable disc so that no further data can be written to it. This is done when the last session's lead-in is written - the next writeable address is not recorded in that lead-in, so the CD recorder in subsequent attempts to write has no way of knowing where to begin writing. It is NOT necessary to close a disc in order to read it in a normal CD- ROM drive.
When a session is closed, information about its contents is written into the disc's Table of Contents, and a lead-in is written to prepare the disc for a subsequent session.
A list of tracks which will be written one after the other in the same session without user intervention. Generally used to create multi-track audio or mixed-mode discs. See the chapter How to Write an Audio Disc for details.
Capital A to Z, digits 0 to 9, and the underscore symbol ( _ ).
In ISO 9660, the space on a CD-ROM where the user data is written. It begins at the address 00:02:16.
In the logical format of a disk or disc, a "branch" of the information tree containing other directories (subdirectories) and/or files.
Error Correction Code. A system of scrambling data and recording redundant data onto disc as it is premastered. On playback this redundant information helps to detect and correct errors that may arise during data transmission.
Error Detection Code. 32 bits in each sector which are used to detect errors in the sector data.
A small program which can be "plugged into" a larger one, usually to enhance the main program's capabilities. All operating systems use extensions to enable them to read compact discs.
A data structure that translates the physical (sector) view of a disc into a logical (files, directories) structure, which the application and user can more easily use to locate files. See also Logical Format.
The recordable disc used in recordable CD systems. 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. This type of disc is therefore also called pre-grooved. A translucent layer of recordable material is laid on top of the polycarbonate, then a reflective layer of gold. On top there are thin layers of lacquer and label.
Four bytes recorded at the beginning of each sector which tell the address of the sector (expressed as a Logical Block Number) and the mode in which the sector is recorded.
The file system used by the Macintosh operating system to organize data on hard and floppy disks. Can also be used for CD-ROMs.
The standard logical format for CD-ROM originally proposed by the High Sierra Group, on which the ISO 9660 standard is based; essentially identical to ISO 9660.
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, in popular use the term "hybrid" often refers to a disc containing both DOS/Windows and Macintosh software, which on a DOS/Windows platform is seen as a normal ISO 9660 disc, while on a Mac it appears as an HFS disc.
An international standard specifying the logical format for files and directories on a CD-ROM.
Or CD-ROM image, image, disc image. A single large file which is an exact representation of the whole set of data and programs as it will appear on a CD, in terms of both content and logical format.
An area at the beginning of each session on a recordable compact disc which is left blank for the session's Table of Contents (track numbers and start-and-stop points). The lead-in is written when a session is closed, and takes up 4500 sectors on disc (1 minute, or roughly 9 megabytes). The lead-in also indicates whether the disc is multisession, and if the disc is not closed, which is the next writeable address on the disc.
The area at the end of a session which indicates that the end of the data has been reached; there is no actual data written in the lead-out. The first lead-out on a disc is 6750 sectors (1.5 minutes, about 13 megabytes) long; any subsequent lead- outs are 2250 sectors (.5 minute, about 4 megabytes).
The smallest addressable space on a disc. Each logical block is identified by a unique Logical Block Number (LBN), assigned in order starting from 0 at the beginning of the disc. Under the ISO 9660 standard, all data on a CD is addressed in terms of Logical Block Numbers. At present, CD recording is supported at one Logical Block per logical sector.
Logical Format or Logical Structure A logical file format such as ISO 9660 translates the sector-by-sector view of a compact disc into a virtual "tree" of directories and files, which makes it easier for both humans and computers to use the information on the disc.
Technically, refers to the process of creating a glass master from which compact discs will be reproduced in quantity. In desktop recordable CD systems, mastering is done together with premastering by the desktop CD recorder, and the term mastering is used generally to mean "recording."
Microsoft DOS extensions for CD-ROM. Allows the DOS operating system to recognize a CD-ROM as a DOS volume.
A compact disc including both computer data and CD-DA tracks. The data is all contained in Track 1, and the audio in one or more following tracks.
To install a compact disc so that the computer recognizes its presence and can read data from it.
To write on-the-fly means to write to CD data referenced in a virtual image without first writing a real ISO 9660 image.
The Philips/Sony specification for Compact Disc Magneto-Optical (CD- MO) and Write-Once (CD-WO) systems.
(Power Calibration Area). A space reserved at the beginning of the disc for calibrating the laser to record to that disc.
A compact disc format based on the CD- ROM XA and Orange Book Hybrid Disc specifications, used to store photographic images for display and printing.
(Program Memory Area) On a recordable disc, an area which "temporarily" contains track numbers and their starting and stopping points (that is, the session Table of Contents) when tracks are written in a session which is not yet closed. When the session is closed, this same TOC information is written in the session lead-in.
A space dividing tracks, recorded before the track data area. The length of the pre- gap varies with the CD recorder and the types of tracks. Where successive tracks are both of data, one track is separated from another by a track pre-gap of 150 sectors (2 seconds). Where successive tracks are of different types, the pre-gap is usually of 225 sectors (or three seconds). If two successive tracks are audio, there may be no pre-gap at all.
The process of preparing data to be recorded onto a compact disc. This includes breaking the data into sectors and recording those sectors with the appropriate header (address) and error correction information. In the case of recordable CD systems, premastering and mastering are done in one operation, resulting in a ready-to-read compact disc.
A space dividing tracks, recorded within the track data area at its end. The post- gap is 150 sectors (2 seconds) long and is required only where successive tracks are of different types. However, because many disc replicators expect a post-gap at the end of every track and may erroneously strip out data sectors if they do not find one, Easy-CD Pro records a post-gap after every track.
The Philips/Sony specification for audio (CD-DA) compact discs.
Small Computer System Interface (pronounced "scuzzy"). An interface which allows up to eight devices to be linked to a single controller.
The smallest recordable unit on a CD. A disc can contain [(75 sectors per second) x (60 seconds per minute) x (number of minutes on disc)] sectors. The amount of data contained in the sector depends on what physical format and mode it is recorded in; for "regular" CD-ROM (Mode 1) data, you can fit 2048 bytes (2 kilobytes) of data into a sector.
As defined under the Orange Book, a recorded segment of compact disc which may contain one or more tracks of any type (data or audio).
Shows the number of tracks, their starting locations, and the total length of the data area of the disc.
Every time you write to CD, you will create at least one track, which is preceded by a pre-gap and followed by a post-gap. Any session may contain one or more tracks, and the tracks within a session may be of the same or of different types (for example, a mixed-mode disc contains data and audio tracks). Using the Cue Sheet you can record more than one track in a single writing.
A database of files to be written to CD, created by dragging & dropping files into the main window. Can be used to write directly to CD on-the-fly, or to master a real ISO 9660 image to hard disk. See the chapter How to Create a Virtual Image for details.
Under the ISO 9660 standard, a single CD-ROM disc.
In ISO 9660, fixed-length records containing vital information about the CD and how to read it.
The book which sets out the standard developed by Philips and Sony for the physical format of compact discs to be used for information storage.
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 | Copyright ©1995 by ISOMEDIA, Inc. For Information, contact Ken Cheney | |
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