Writable CD, software-free: DirectCD and PacketCD turn 2.0

Emedia Professional, May, 1998 by Robert A. Starrett

Packet writing has enabled new and useful tools that allow CD media to be used for non-traditional applications. Backup products like Seagate's Backup Exec for CD-R/CD-RW and Dantz Retrospect are two excellent examples of the use of packet recording to move CD media into new application areas.

But by far the most widely used and popular applications of packet-writing software are those that make recording to CD seem software-free, like writing to floppy disks or hard drives. Two widely installed packet tools, DirectCD and CeQuadrat's PacketCD, eliminate the software learning curve that has made CD recording a relatively high-maintenance storage option by enabling drive-letter access to any packet-enabled CD-Recordable or CD-ReWritable drive. Thanks to packet-writing tools, users can move files to and from the CD media just as they would with a hard drive or floppy. In the case of CD-RW media, users can actually erase files and thus re-use space on the disc--all without the interface intricacies of traditional premastering software and the capacity-consuming overhead of multisession writing.

Another great thing about packet writing is that buffer underrun, that frustrating occurrence that plagued many CD users in the past, is eliminated as a possible error because of the way packet writing works. According to the CD-UDF standard--the file system used by DirectCD and PacketCD--"The file system is almost completely underrun-proof. The only parts that must be recorded without an underrun are the two volume descriptor sequences. As these structures are no more than five sectors each, this should not present a problem."

But how clear is the packet-writing message to date, and how well are the tools living up to their ground-breaking promise? Is the popularity of these programs due to their stability, performance, and usefulness, or are they so widely installed only because one or the other comes bundled with just about every writable and rewritable CD drive sold today? The case to be made for these tools in their 1.0 incarnations was a little weak, mostly because of their lack of support for true direct-overwrite capability on CD-RW media and some early-version instabilities and incompatibilities.

Smart Storage's FloppyCD, an evolution of the CD-R Extensions software the company has been bundling with JVC CD-R drives for years, approaches the capabilities of DirectCD and PacketCD, but finds its primary implementation in JVC drives and on network systems as a component of Smart Storage's SmartCD network recording management tool. With FloppyCD/SmartCD aimed squarely at alternate channels, Adaptec and CeQuadrat carry the torch for direct drive-letter access to CD-R and CD-W, with no other major players competing for the desktop market at this time.

And in the products' 2.0 incarnations, it's hard to argue that DirectCD and PacketCD don't carry that torch proudly. With improved stability, greater interchangeability, and--most eagerly awaited of all--the ability to rewrite CD-RW media file-by-file, these products more than earn their place on the desktops they (often incidentally) land on. But which packet tool to pick? Well, it depends...

PACKET-TO-PACKET COMPATIBILITY: A KEY CONCERN

The real impetus for the development of packet-writing products was the approval by OSTA, the Optical Storage Technology Association, of CD-UDF, a subset of the UDF (Universal Disk Format) standard agreed upon by OSTA in 1996. Even though either DirectCD or PacketCD or both apparently take some liberties with the UDF specification, since their discs are only interchangeable under certain circumstances, it's a good bet that future versions will clean up these incompatibilities, whatever their origin.

But what are the consequences of current compatibility shortfalls? Imagine, a year or two down the line, a packet-packed world with packet-written CD-R discs on every desktop and the majority of PC users employing one tool or the other regularly, but not both. What happens if you use PacketCD and your cousin uses DirectCD? Can you exchange discs and read and write to them? The answer is yes and no. Interestingly, there is quite a mix of phenomena that can occur when exchanging discs between the programs. The best case, and some comfort to users, is that both programs will read and write to an unclosed disc formatted by the other program after the first data has been written by the program that formatted the disc. PacketCD can write to a disc that has been formatted but not written first by DirectCD, but DirectCD will not recognize or write to a disc that was formatted by PacketCD, unless you have first written data to that disc with PacketCD. To move discs from PacketCD to DirectCD, you must format the disc with PacketCD, then write something to that disc with PacketCD. DirectCD will then recognize the disc and use it as its own. The other option is to format with DirectCD, then transfer the disc to a PacketCD machine which will recognize and use the disc without the necessity of having to write data to it with DirectCD first. In other words, you can format and write data with DirectCD and then add data with PacketCD, then go back to DirectCD and so on. The reverse is also true. A disc formatted with PacketCD and with the initial data written with PacketCD can be added to by DirectCD, then written and read again by PacketCD, then written and read by DirectCD again.