Ricoh MP5120A IDE DVD+RW - Page 1

Ricoh enters the DVD Recording with the first DVD+RW recorder!

- Introduction
DVD recording has been something that users kept dreaming for a long time now. The increased storage capacity among with the option to create DVDs working at stand alone players is the strongest points of the DVD format.

During the evolution of DVD recording, 8 companies offered an alternative solution for DVD recording under the name of "DVD+RW". DVD+RW has been standardized by 'DVD+RW Alliance' that consists of eight companies including those recently promoted CD-R/RW: Sony (Japan), Dell Computer (USA), Thomson Multimedia (France), Hewlett-Packard (USA), Philips (Netherlands), Mitsubishi Chemical (Japan), Yamaha (Japan), and Ricoh (Japan).

The 8 companies promises ultimate performance among with maximum compatibility: "...Recent technological advances, including Broad-band communication, have brought about the need for larger storage capacity of recording media. PCs are becoming a remarkably popular means of viewing TV programs. We see that more opportunities to process even larger information/data will lead to various needs for removable, large-capacity media that enable seamless data exchange between PCs and AV appliances. DVD+RW is the rewritable DVD standard with capacity of 4.7 GB to take all the needs into reality..."

- DVD+RW: Physical format

DVD+RW at a glance:

- Single-sided (4.7 GB) and double-sided (9.4GB) discs option
- Uses a bare disc - no cartridge required
- 650 nm laser (numerical aperture 0.65)
- Constant linear data density
- CLV and CAV recording
- Write speeds from 1x to 2.4x DVD-Video data rates
- Defect management handled by the drive
- Quick formatting
- Recording: (Sequential and random recording, 32 kB ECC blocks, Lossless linking)

DVD+RW format allows ‘CAV recording’ (Constant Angular Velocity). Due to the constant rotation speed of the disc CAV recording allows for fast random access. Yet two other benefits are the incorporation of ‘Defect management’, especially designed for reliability of the data, and ‘Quick formatting’, enabling instant use of blank discs. Those benefits mentioned above make this format ideal to use for high performance systems. For video applications the format has the capability of ‘lossless linking’ allowing to use variable bit rate recording for longer playing times.

- The 'Lossless linking' feature

With DVD + RW, it is possible to perform lossless linking, i.e. to suspend and continue the writing process without linking loss. The physical structure of DVD+RW disc is designed to be compatible with DVD-ROM, and a combination of HF (High Frequency) Wobbled Groove and ADIP (Address In Pre-Groove) correction keeps the data connection points after adding or editing at 1 micron or less (Lossless Linking function). This technology provides the excellent compatibility even after data is added or edited. DVD+RW drives are also compatible with DVD+RW Video Recorder, integrating PC and AV worlds.

Additionally, lossless linking makes it possible to replace any individual 32 kB block (recording unit) by a new one, without losing compatibility. For lossless linking, it is imperative to write any data block in the correct position at a high degree of accuracy – within a single micron.

In conventional optical recording drives the write/pause operation causes a rather big area (usually one sector = 2 Kbytes) to be corrupted due to poor linking accuracy at the border between two contiguously written pieces of information.

This linking loss makes the disc incompatible with existing read-only devices like DVD-Video players and DVD-ROM drives.

- The compatibility

DVD+RW recorders have designed to be two-way compatible, which means that:

- Stand Alone DVD+RW recorders will play DVD-Video discs
- Recordings made on rewritable discs with a DVD+RW recorder can be played in most DVD-Video players as well as in PCs with a DVD-ROM drive

All physical parameters of DVD+RW fit within the DVD-ROM specification. The reflectivity is in the same range as the dual-layer reflectivity specification of a read-only disc and the density is the same as for the single layer specification:

However Ricoh states, that the recorded media may not be readable on approximately 30% of existing DVD-ROM drives and DVD-Video players. For that propose Ricoh (DVD-ROM & DVD-Video players) and Philips have lists of compatible drives. Those lists contain at 47 DVD players and 19 DVD-ROM drives that support DVD+RW format. This does not mean that a non-listed drive does or not support DVD+RW.

- The Defect Management & Physical Formatting System

A DVD+MRW system according to the specifications in this document will offer the following features:

- Full random access
- Data transfer between host computer and drive is based on 2K User Data Frames
- Defect Management handled by the drive (or by a dedicated Read-Only device driver)
- Physical formatting performed in background by the drive (without interaction with the host computer)
- Disc will be available for use immediately after insertion
- Ejecting the disc before the Background Formatting process is completed is possible

- Shortened formatting time (Featuring Background Formatting)

* Drive starts formatting for the random access write with a small portion of disc first (lead-in area and part of the data area, required to start writing). It then resumes for the remaining portion automatically in the background when there is no writing or reading operation (Background Formatting). This feature enables to start initial writing in just two to three minutes.

* Background formatting shall be suspended should additional reading/writing be required.

* Discs that are only partially formatted can be ejected from the drive, maintaining the compatibility with existing DVD-ROM drives.