7.3 4.7 GB DVD-RAM Format

Recording media	phase change disc
disc dimensions	120 mm diameter, bonded 0.6 mm thick substrates
laser wavelength, NA	650nm, 0.6
modulation method	8/16 encoding
sector size	2kB
ECC block size	32kB
error correction method	RSPC
capacity	4.7 GB (one sided)
disc format	ZCLV
number of data area zones	35zone
addressing method	CAPA (Complimentary Allocated Pit Addressing)
recording bit length	0.28m/bit
recording method	mark edge recording
track pitch	0.615 m, land and groove
tracking method	push-pull
file system	UDF
user data rate	22.16Mbps

After the release of the DVD-RAM version 1.0 specification, version 2.0 for 4.7 GB discs was created. The major differences between version 1.0 and version 2.0 are given below.

1. 4.7 GB capacity Version 2.0 increases the capacity of a single disc side from 2.6 GB to 4.7 GB, the same as for DVD-ROM. This was accomplished by decreasing track pitch from 0.74 m to 0.615m and recording bit length from 0.41 m/bit to 0.28 m/bit.
2. 22.16 Mbps standard data rate VThe data rate of version 1.0 is the same as DVD-ROM, at 11.08 Mbps. Version 2.0 doubles the standard data rate to 22.18 Mbps to improve data recording capability.
3. Defect management method Version 2.0 incorporates a new defect management method to support real-time recording of audio and video data.

7.4 1.46 GB (8 cm) DVD-RAM Format

Recording media	phase change disc
disc dimensions	80 mm diameter, bonded 0.6 mm thick substrates
laser wavelength, NA	650nm, 0.6
modulation method	8/16 encoding
sector size	2kB
ECC block size	32kB
error correction method	RSPC
capacity	1.46 GB (one sided)
disc format	ZCLV
number of data area zones	14zone
addressing method	CAPA (Complimentary Allocated Pit Addressing)
recording bit length	0.28m/bit
recording method	mark edge recording
track pitch	0.615 m, land and groove
tracking method	push-pull
file system	UDF
user data rate	22.16Mbps

The DVD-RAM version 2.1 specification was based on the 4.7 GB DVD-RAM version 2.0 specification to define an 8 cm disc. The major differences between the 8 cm disc and the 4.7 GB, 12 cm disc are as follows.

1. 8 cm diameter The disc size was reduced from 12 cm to 8 cm. In addition, an 8 cm case is also provided.
2. 1.46 GB capacity The recording capacity dropped from 4.7 GB to 1.46 GB as a result of the decrease in size. The track pitch is 0.615 m, and the recording bit length is 0.28 m/bit, the same as with the 4.7 GB disc.
3. 14 zones The number of zones was reduced from 41 in the 4.7 GB disc to 14.

All the remaining specifications are the same as for the 4.7 GB disc.

Source: http://www.pioneer.co.jp/crdl/tech/index-e.html