This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
The numbers after the model name (e.g. "CDR-102 (4x2/512K)") refer to the
read and write speeds of the unit and the size of the write buffer. "4x2"
would be a double-speed writer that's also a quad-speed reader. If it just
says "?x2", the write speed is double-speed and the read speed isn't known
(but presumably is at least 2x). Buffer sizes written with a '+', e.g.
"2MB+", indicate that the buffer can be expanded further.
If the recorder can write to CD-RW media, the specification will include a
third value, e.g. "6x4x2/1MB" would be a drive that reads at 6x, writes to
CD-R media at 4x, and writes to CD-RW media at 2x.
Some manufacturers present the speed ratings in a different order, often
write/rewrite/read. Some drives that support reading of DVD-ROM will
be written write/rewrite/read/dvd-read. There is no standard approach.
Many units are repackaged versions of other manufacturer's devices,
sometimes with slight changes in the firmware. Value-added retailers have
been known to switch to a different manufacturer's drive without notice, so
don't assume that everything here is accurate.
The interface is listed for each drive. "SCSI" means any form of SCSI
(SCSI-2, SCSI-3, wide, narrow, ultra, etc). IDE means any ATAPI interface
(e.g. Ultra-DMA/33). USB (1.x or 2.x), parallel-port, FireWire, and PCMCIA
refer to interface styles for external drives (which are usually just
internal ATAPI devices placed inside an enclosure with a power supply
and an ATAPI converter).
Many of the models listed have been discontinued in favor of newer models,
and some of them have yet to be released, so you will probably not be able
to find all of the models listed here for sale.
If you're new to SCSI, take a look at the comp.periphs.scsi FAQ,
http://www.faqs.org/faqs/scsi-faq. It covers both novice and advanced
questions. If you want specs, try http://www.t10.org/.
A wealth of information on Enhanced IDE and other storage technologies
is available from http://thef-nym.sci.kun.nl/~pieterh/storage.html
If you want to debate the merits of SCSI vs EIDE, please read
Some brief notes: ATA (AT Attachment Interface) is the official name
for IDE (Integrated Drive Electronics) interfaces. ATAPI is the ATA
Packet Interface, commonly used for controlling CD-ROM and tape devices.
The ATA-2 changes grew out of vendor-specific "Enhanced IDE" implementations.
There have been subsequent enhancements (ATA-3, ATA/ATAPI-4, etc).