MAM-A | Technology

	Current DVD Media Formats

Type	Slides	Layers	R/W	Data Capacity	Video Capacity	Notes
DVD-5	1	1	Play-Only	4.7 GB	2+ hrs
DVD-9	1	2	Play-Only	8.5 GB	4 hrs
DVD-10	1	2	Play-Only	9.4 GB	4.5 hrs	2 X DVD-5
DVD-18	2	2	Play-Only	17 GB	8+ hrs
DVD-R	1	1	Write once Read Many	3.95 - 4.7 GB	2+ hrs
DVD-RAM	1	1	Effaçable	2.6 GB	1 hrs	Per side
DVD-RW	1	1	Effaçable	4.7 GB	2+ hrs	Per side

	DVD sides and layers

This is the most basic configuration for DVD. It has a maximum storage capacity of 4,7 GB. This 4,7 GB is 7 times the capacity of CD

Single-Sided, Single Layer Disc (4.7GB)

Double-Sided, Single Layer Disc (9.4GB)

This configuration provides a total of 9,4 GB.half of the data is on the second side. It requires flipping the disc

Also referred to as " RSDL ", reverse spiral dual layer. This configuration provides a total of 8,5 GB on one side using an additional 3,8 GB on the second layer.

Single-Sided, Dual Layer Disc (8.5GB)

Double-Sided, Dual Layer Disc (17GB)

This configuration provides the maximum. Capacity of 17 GB. Half of the data is on the second side.

	DVD-R

DVD-R discs make use of a similar technology to CD-Rs but with a different dye and smaller geometries. There are two versions with different storage capacity :

Parameter	Ver 1.0	Ver 1.9	Ver 2.0	Ver 2.0
	Authoring	Authoring	Authoring	General
Slides	1 or 2	1 or 2	1 or 2	1 or 2
Capacity (Gb)	3.95 per side	4.7 per side	4.7 per side	4.7 per side
Availability	Depuis 1997	Depuis 1999	Depuis 2000	Début 2001
Recording method	Organic dye layer, 635nm laser			650 nm laser
Min. pit length (microns)	0.44	0.40
Track pitch (microns)	0.80	0.74
Format de piste	Wobble pre-groove		Wobble pre-groove
Modulation and error correction	8 to 16 & RSPC

DVD-R is fully compatible with DVD-ROM, DVD-Video and DVD-Audio so that recorded DVD-R discs can be read on any suitable DVD hardware, depending on the format of the data contained on the DVD-R.

DVD-R discs will comprise the following data areas :

Power Calibration Area (PCA).

Recording Management Area (RMA).

Lead-in Area.

Data Recordable Area.

Lead-out Area.

	DVD-RW

Format type	Re-Writable
Technology	Phase-change recording on pre-recorded spiral wobbled groove with land-prepits
Format owner	DVD Forum
Storage capacity	4.7 X 10⁹ Bytes per layer max.
Drive compatibility	DVD-R/RW drives

Disc diameter	120 mm
Disc Thickness	2 X 0.6 mm
Data Encoding Scheme	EFM+
Rotation	CLV

DVD-RWs employ the phase-change recording method.

In this technique, laser beams aiming at the recording film change its phase between the recording and erasing states. In the erased phase, each tiny pit on the disc reflects light. The laser alters the reflective characteristics of pits during recording. Therefore, the way light reflects from each pit indicates whether it is in the recorded stage or the erased stage. For data reproduction, weak lasers aim at the disc, to detect the difference in the light reflecting from erased areas and areas that contain data.

The recording layer's phase-change material becomes amorphous and thus less-reflective during recording, and returns to a very reflective crystalline state during data erasure. The DVD Forum is especially interested in making DVD-RWs compatible with DVD-ROM drives. Some electronic manufacturers are developing DVD-RW recorders for home use, to replace VCRs.

	DVD-RAM

Item		DVD-RAM 26	DVD-RAM 52
Sides Used		Single sided	Double sided
Recording Capacity		2.6 GB	5.2 GB
Laser Wavelength		650 NM
Aperture of Objective Lens		0.6
Recording Layer Materials		Phase Change Recording Materials
Recording Format		Wobbled Land and Groove
Substrate Materials		Polycarbonate
Minimum Data Bit Length		0.41 µm
Track Pitch		0.74 µm
Sector Size		2,048 Bytes
Modulation Method		8/16, RLL (2,10)
Error Correction Code		Reed-Solomon Product Code
Reference Data Transfer Rate		11.08 Mbps
Dimensions	Disk Diameter	120 Ø mm
	Disk Thickness	1.2 mm
	Center Hole Diameter	Ø 15.0 mm
	Cartridge Dimensions	138 x 125 x 8 mm
Operating Environment		5°C ~ 60°C (41°F ~ 131°F)
		3% ~ 85 % RH (No condensation)

DVD-RAM discs use phase change recording where the active layer is made to change between amorphous and crystalline state by means of a laser at different power.

DVD-RAM discs use Zoned CLV (ZCLV) method instead of CLV, where the angular velocity continuously changes. Within each zone the data is written/read using the CAV method, the angular velocity changing from zone to zone to maintain a constant average linear velocity. The data is written on both land and groove, the address information being molded into the disc as pits.

Difference between CD and DVD