Glossary of DVD Terms
- API
- Application Program Interface. This is a code module or set of modules that
other programs can make calls to or "ask to perform specific functions."
- Authoring
- This refers to the process of designing and creating the content of a DVD
title. The more complex and interactive the disc, the more authoring is required.
Beta versions and archiving require DVD-RAM. SAI offers solutions to authoring.
- CD
- Compact Disk. A media that uses a single track, like phongraph records.
This layout of data makes random access of data take longer, this is commonly
referred to as a long seek time. CD's have a capacity of 640MB.
- CD-R
- Compact Disc, Recordable. A technology defining a way for CD media to be written to once. CD-R media looks almost like a standard CD. CD-R drives have
the ability to write to CD-R media. Capacity of CD-R media is measured in minutes, as this technology was adapted from the same as audio recordings. At current there are four types of media 5.75 min (50 Meg), 20 min (180 Meg), 74 min (650 Meg), and 80 min (700 meg). This is desinged for permenant files as the data on the CD-R cannot be changed.
- CD-RW
- Compact Disc, Re-Writeable. Improves upon CD-R. These drives are based on the CD-R technology with the ability to be re-written. At current only 74min (650 Meg) is the only available media.
- CD-UDF
- See UDF-bridge.
- DVD
- DVD, which once stood for Digital Video Disc or Digital Versatile Disc, is the
next generation of optical disc storage technology. It's essentially a bigger,
faster CD that can hold video as well as audio and computer data. DVD aims to
encompass home entertainment, computers, and business information with a single
digital format, eventually replacing audio CD, videotape, laserdisc, CD-ROM, and
perhaps even video game cartridges. DVD has widespread support from all major
electronics companies, all major computer hardware companies, and about half of
the major movie and music studios, which is unprecedented and says much for its
chances of success. This is a standard for a type of optical media that will use the UDF file
system. Capacities for single sided is 4.7GB's for single layer and 8.5GB's for dual-layer disks.
Capacities for double sided is 9.4GB's for single layer and 17GB's for dual-layer
disks.
- DVD Forum
- A collection of organizations that contributed to the DVD definition. Members
include Hitachi Ltd., Matsushita Electric Industrial Co. Ltd., Mitsubishi
Electric Corporation, Pioneer Electric Corporation, Sony Corporation, Thomson
Multimedia, Time Warner, Inc., Toshiba Corporation, and Victor Company of Japan
Ltd.
- DVD-RAM
- This is true Read/Write media. Data can be record and erased many times.
DVD RAM will use a technology based on Phase Change technology. (Capacity of
approx. 2.8GB)
- DVD-R
- DVD Recordable. Same write once concepts as CD-R but with the benefits of
DVD media. Single-sided, single-layer media capacity of approx. 3.6GB)
- DVD-ROM
- The base format of DVD. ROM stands for "read-only memory" referring to the
fact that they can not be recorded on.
- DVD+RW
- Digital Versital Disc plus Re-Writeable. Still in this development stages, this device will allow the same as CD-RW except on the larger data scale as the DVD. Using unique media (DVD-RW) will be capable of storing 4.7 Gigbytes on one piece of media.
- DVD-Video
- Using the same techonolgy for DVD, this format is desiged to be used to store movies on a DVD medium. Most DVD drives have the ability to read DVD-Video.
- ECMA 167
- A predecessor to the ISO 13346 Specification.
- File System
- An "organized" defined way to store and catalog files on a disk. A file
system is used by the computer to find and store files.
- Fork
- As in resource-fork and data-fork. Essentially a separate sub-file of the
actual total file. At a low level each fork is actually a separate file. This
allows a separation between different types of information that can be grouped
together and accessed by just looking at "one file". The Mac uses two forks for
each file. Windows NT can have many "data-forks" for each file.
- ISO-13346
- International Standards Organization spec # 13346. This is a set of
standards that OSTA looked at and pulled from to develop UDF.
- ISO-9660
- A file system that has been used for CD's to provide a standard that Mac's,
PC's, and Unix machines could read. ISO 9660 is inadaquate for the higher
capacity recordable and erasable DVDs.
- Magneto Optical
- A technology for optical storage that depends on a laser and a magnet. The
magnet of the drive head reads the media and writes to the media. The laser
heats the area to be written to, to a high enough temperature so that the
magnetic polarity of the area can be changed.
- MMCD
- MultiMedia CD. Sony's term for their DVD disks.
- MPEG2
- Moving Picture Experts Group. The second set of flexible compression
standards created by this group is called MPEG2. This set of standards takes
advantage of the fact that over 95% of digital video is redundant, however some
portions are much less redundant. MPEG2 handles this by using higher bit rates
for more complex pictures and lower bit rates for simple pictures. With MPEG2
only about 4 or 5 minutes (depending on quality) of video would fit on a 4.7GB
DVD.
- Native
- As in Native file system or PowerMac Native. This term is used to refer to
the specific machines standard way of doing something. The Native file system of
a operating system is the file system that the operating system has built in.
- OSTA
- Optical Storage Technology Association. OSTA is a non-profit organization,
incorporated as an international trade association in 1992 to promote the use of
writable optical technologies and products for storage of computer data. OSTA
played a large role in defining UDF. They hold the trademark for UDF. OSTA does
not create standards, but it helps the optical storage industry define practical
implementations of standards to assure compatibility of resulting products.
- Packets
- In this glossary, packets refers to a small chunk of data (about 16KB) as
opposed to the complete set of data that can be up to the size of the media being
written to (CD's hold 640MB)
- PreMastering
- This is generally defined to include compression and conversion of all data,
verifying compliance with the DVD specification and writing the data to a UDF
bridge or UDF format disc image. Once a title has been pre mastered, its ready
for simulation or testing with one-off copy and then sending out for replication.
- Phase-Change
- A technology for optical storage that only depends on the laser light. (As
opposed to Magneto Optical.) Drives that use this technology do not need a
magnet. The media shifts the "phase" of the laser light when reading and the
laser changes the media to reflect the laser differently when writing.
- Seek Time
- This refers to the amount of time it takes to find the correct position on
storage media so that data can start to be read.
- TWG
- Technical Working Group. Comprised of Hewlett-Packard, Compaq Computer,
Apple Computer, Kodak, IBM, and Microsoft Corporation. These companies
established the basic requirements of DVD. The requirements include: single
interchange standard; backward read compatibility with existing CDs; forward
compatibility with future read/write and write-once discs; single file system for
all disc types; low cost; no mandatory container; reliable data storage and
retrieval; high on-line capacity; and high performance for sequential and
non-sequential data.
- UDF
- Universal Disk Format. A spec for a file system that OSTA had a big part in
outlining. This file system was designed to be able to handle files from all
other common file systems (computers). i.e. It can handle Mac resource forks and
Windows95 long file names. UDF was also defined to be able to be enhanced for
future systems. NSR ECMA 167 and ISO 13346 are predecessors to UDF.
- UDF-bridge
- Allows a link between ISO 9660 and UDF. Using UDF Bridge one copy of a set
of data can be put on a piece of media and both ISSO 9660 compatible readers and
UDF readers l be able to access the information. Also known as CD-UDF or CD-RW.
- WORM
- Write Once Read Many. This is used to reference CD-R or DVD-R type devices and media. The information is written once to the media and cannot be edited.
- Write UDF!TM
- This is SAI's implementation of the UDF file system specification. It is the
only implementation that we know about that is available today that can be used
on personal computers. It is designed as an "API" and we have applications to
demonstrate its capabilities. The applications allow the user to exchange files
between the computers native file system and UDF. (Some native file systems are
HFS (Mac), FAT (DOS, Windows).) The volume and file size maximum capacity is
currently 4GB, although larger capacities are currently under constuction.
- Write DVD!TM
- This is SAI's implementation for Windows 95/98/NT/2K native file system. User's
can use standard O/S protocol, such as the explorer to access a disk formatted in
the UDF format..
Home | Company Overview
| Product
Listings | Sales |
SAI News | Tech
Support | DVD Solutions
| Employment Opportunities