Sony RDR-GX7 - Manual (Page 4)

Recordable DVD specifications
At present, there are five different types of Write-once and Re-
writable DVD media, each with their own specifications. These
different media include DVD-R, DVD-RW, DVD+RW, DVD+R
and DVD-RAM. The following is a brief explanation of their
respective development and features.
■ DVD-R
This is a “write-once” format, and as with CD-R, it can only be
recorded once. The DVD Forum has formalized this
specification as DVD-R (specification name: DVD-Recordable).
Since DVD-R was originally developed as a way to create master
discs and operation testing discs for DVD-ROM as well as DVD-
Video, one of its major features is very high compatibility with
DVD-Video. The data capacity was formally set at 4.7 Gbytes
with the Version 2.0 specification (for authoring) established in
February, 2000, and for the Version 2.0 specification (for general
use) established in May, 2000 and its capacity is the same as
other recordable DVD media.
■ DVD-RW
Recordable DVD media that can be “re-written” with new
content is called “rewritable.” These include DVD-RW
(specification name: DVD Re-recordable), which was formalized
as a standard by the DVD Forum. Specifications are very close to
those of DVD-ROM and DVD-Video. DVD-RW is compatible
with two different recording formats, including Version 1.0
specifications for DVD Video Recording format, plus the Version
1.1 standard for DVD-Video format recording, adopted March
2000, which enables playback on conventional DVD players.
The discs can be rewritten approximately 1,000 times.
■ DVD+RW
DVD+RW (specification name: DVD+ReWritable) was
announced as a re-writable DVD specification in October 1999.
It is being promoted for adoption in CD-R/RW drives and media
primarily by a group of eight manufacturers called the DVD+RW
Alliance*. The recording method uses the same phase
modulation technology as used in DVD-RAM and DVD-RW.
Importance is placed on compatibility with existing DVD-ROM
drives and DVD players. Random reading and writing operations
are also highlighted, to enable application as a data storage
medium for computers. The discs can be rewritten approximately
1,000 times.
* Dell, Hewlett-Packard, Mitsubishi Chemical Corporation, Philips
Electronics, Ricoh Company Ltd., Thompson Multimedia, Yamaha
Corporation, and Sony Corporation.
■ DVD+R
In January 2002, the DVD+RW Alliance developed DVD+R
(specification name: DVD+Recordable) based on DVD+RW, but
since mistaken erasures are not possible, it is ideal as a storage
medium. Since the reflection ratio is higher than that of
DVD+RW, there is higher playback compatibility with
conventional DVD playback equipment.
■ DVD-RAM
DVD-RAM (specification name: DVD Rewritable) is a
specification recognized by the DVD Forum. In July 1997, the
Version 1.0 specification was announced, featuring the disc in a
cartridge and 2.6 Gbytes capacity per disc side. Then, in
September 1999 the Version 2.0 specification was announced,
with 4.7 Gbytes capacity per disc side for a total of 9.4 Gbytes.
DVD-RAM is not compatible with existing DVD-ROM drives
and DVD players. However, each side can be re-written
approximately 100,000 times, making it a highly functional
medium for computer data storage.
While recordable discs are most commonly distinguished by the
five different disc names for their physical formats, they will
have different characteristics and capabilities depending upon the
recording formats (application formats) used with them.
A detailed explanation of formats will be given in Chapter 2.
Chapter 1
The Era of Recordable
DVD
RDR-GX7 Technical Notes
4
DVD-R
DVD-RW
DVD+RW
DVD+R
DVD-RAM
1997 1998 1999 2000 2001 2002 2003
10
Single Side 3.0 Gbytes
Double Side 6.0 Gbytes
03
Ver. 1.0
Single Side 4.7 Gbytes
07
Ver. 1.0
Single Side 2.6 Gbytes
09
Ver. 2.0
Single Side 4.7 Gbytes Double Side 9.4 Gbytes
01
Ver. 1.0
Single Side 4.7 Gbytes
11
Ver. 1.0
03
Ver. 1.1
Single Side 4.7 Gbytes
07
Ver. 1.0
Single Side 3.95 Gbytes
02 Ver. 2.0 for Authoring Single Side 4.7 Gbytes
05 Ver. 2.0 for General Single Side 4.7 Gbytes
Note: The issue dates of the documents listed above are from the original versions of the copyright owners. However, the DVD+RW 3.0 Gbyte and 6.0 Gbyte versions only are ISO/IEC 16969:1999.
History of Recordable DVD
At present, high speed, recordable discs are being
developed for each of these formats. In the near future,
these discs will become available and are expected to
improve data storage capabilities for computers.