Chapter 1 the era of recordable dvd – Sony RDR-GX7 User 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

DVD-R

DVD-RW

DVD+RW

DVD+R

DVD-RAM

1997

1998

1999

2000

2001

2002

2003

Single Side 3.0 Gbytes

Double Side 6.0 Gbytes

Ver. 1.0

Single Side 4.7 Gbytes

Ver. 1.0

Single Side 2.6 Gbytes

Ver. 2.0

Single Side 4.7 Gbytes Double Side 9.4 Gbytes

Ver. 1.0

Single Side 4.7 Gbytes

Ver. 1.0

Ver. 1.1

Single Side 4.7 Gbytes

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.