This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
See http://www.wpinet.com.sg/ [site gone?]
CDR-432 (4x2/1MB;SCSI, based on the Philips CDD2000)
CD-R 622 (6x2/1MB;IDE)
CD-R 632P (6x2/1MB;SCSI, based on the Philips CDD2600)
The CD-R 622 does not support disc-at-once recording. According to the
CDRDAO "readme" file, it is possible to upgrade the 622 (and its Memorex
cousin) by writing the D4.0 ROM image for the CRW-1622 to a 27c020 PLCC
EPROM and replacing the socketed ROM chip in the drive.
The CDRW-622 supports packet writing, and is flash upgradeable.