This is a part of WholeFAQ.html, an extended FAQ about CR-Roms, CR-r/w and DVD's. The complete file may be downloaded from: http://www.cdrfaq.org/.
Packet writing is an alternative to writing entire tracks or discs. It allows you to write much smaller chunks, down to the level of individual files. With track-at-once recording there's a maximum of 99 tracks per disc, a minimum track length of 300 blocks, and an additional 150 blocks of overhead for run-in, run-out, pregap, and linking. Packet writing allows many writes per track, with only 7 blocks of overhead per write (4 for run-in, 2 for run-out, and 1 for link). Since it's possible to write packets that are small enough to fit entirely in the CD recorder's buffer, the risk of buffer underruns can be eliminated.
Information on packet-writing software follows. It is in general a bad idea to have more than one installed at the same time.
UDF is an acronym for the humbly-named "Universal Disk Format". It's a specification for a filesystem intended for use on write-once and rewritable media. It's currently being used for DVD and some of the CD-R/CD-RW packet writing software (e.g. Roxio DirectCD).
Platforms supported: Windows (95, NT, 2K), Mac
See http://www.roxio.com/
UDF-based packet writing software. Check the compatibility list on the web site to see if it works with your CD recorder and your firmware revision level.
DirectCD for Windows versions older than 1.01 conflicted with some scanners. Be sure to check the Roxio web site for the latest version. Note that DirectCD for Windows 1.x and 2.x may not support the same set of drives on all operating systems; for example, 2.0 only worked with drives capable of using CD-RW media. If you're running WinNT, you need 2.x.
NOTE: There seems to be a great deal of misinformation about how to disable DirectCD for Windows. See section (3-45) for more information.
One other note about DirectCD for Windows: in some situations you may have trouble reinstalling it. If so, try removing (or renaming) scsi1hlp.vxd, usually found in c:\windows\system\iosubsys\.
Uninstalling DirectCD v3.01 or v3.01c may disable access to CD-ROM drives under WinXP and Win2K. See section (4-49) for details.
Platforms supported: Windows
See http://www.cequadrat.com/
(CeQuadrat was purchased by Adaptec in July 1999, and is now part of Roxio.)
UDF-based packet writing software. Recent versions offer transparent data compression, potentially increasing the disc capacity.
Platforms supported: Windows (NT)
[ product has been discontinued ]
Packet writing software intended for shared environments.
Platforms supported: Windows (95)
[ product has been discontinued ]
Originally released by JVC as "CD-R Extensions".
Does variable-sized packet writing that leaves you with an ISO-9660 Level 1 CD-ROM (constrast to the ISO-9660 Level 3 disc produced by some other packet writing solutions). This should make it possible to read the finalized CDs on operating systems other than Win95/NT.
Platforms supported: Windows (95, NT, 2K)
See http://www.vob.de/us/products/consumer/InstantWrite/index.htm
See http://www.vobinc.com/
UDF packet-writing software. Supports DVD-RAM and drag-and-drop audio CD creation. Compatible with discs created by DirectCD.
Comes with a backup package called InstantBackup.
Platforms supported: Windows (95)
[ product has been discontinued ]
Packet writing for CD-RW. Appears to be less ambitious but far simpler than its competitors.
Read-compatible with Roxio DirectCD (i.e. you can read DirectCD discs if you have this installed).
Also sold under the Sony label.
Platforms supported: Windows (95, 2K)
See http://www.ahead.de/
UDF packet-writing software. Only works with CD-RW discs.
Platforms supported: Windows (95, NT, 2K, XP)
See http://www.oaktech.com/products/recording_software/simplicd.html
Part of the SimpliCD package. UDF packet-writing for CD-RW discs.
[ Unclear if this is related to the SimpliCD product formerly published by Young Minds Inc. ]
Platforms supported: Windows (95, NT, 2K, XP)
See http://www.ntius.com/ (demo available)
UDF packet-writing software. Uses Windows-Explorer-style interface. Only works with CD-RW discs.
Platforms supported: Windows (98, 2K)
See http://www.hp.com/ (for HP DLA)
Most users will encounter this as HP DLA, sold with a Hewlett-Packard drive. Some documentation is available from http://www.benq.com.sg/service/cdr/manuals/veritas/DLA%20User%20Guide.pdf.