Hardware Reference
In-Depth Information
two for run-out, and one for linking. Packets can be of fixed or variable length, but most
drives and packet-writing software use a fixed length because dealing with file systems
that way is much easier and more efficient.
With packet writing, you use the UDF version 1.5 or later file system, which enables the
CDtobetreatedessentiallylikeabigfloppydrive.Thatis,youcanliterallydraganddrop
files to it, use the
copy
command to copy files onto the disc, and so on. The packet-writ-
ing software and UDF file system manage everything. If the disc you are using for packet
writing is a CD-R, every time a file is overwritten or deleted, the file seems to disappear,
but you don't get the space back on the disc. Instead, the file system simply forgets about
the file. If the disc is a CD-RW, the space is indeed reclaimed and the disc won't be full
until you literally have more than the limit of active files stored there.
Unfortunately, Windows versions up through Windows XP don't support packet writing
ortheUDFfilesystemdirectly,sodriversmustbeloadedtoreadpacket-writtendiscs,and
a packet-writing application must be used to write them. Fortunately, though, these typic-
ally are included with CD-RW and DVD rewritable drives The ISOBuster data recovery
program reads the contents of damaged CD, DVD, and BD discs and can also be used as
a UDF reader.
Windows 7 and Vista support UDF much more thoroughly than previous Windows
versions. They are able to format optical media using the Live File System
(LFS—Microsoft'stermforUDF2.01),olderUDFversions(1.02,1.5),andthenewUDF
version2.5,aswellasMastered.UDF2.01discscanbereadbyWindowsXPorlater,and
they support drag-and-drop file copying on Windows 7 or Vista. UDF version 1.02 is de-
signed for use with DVD-RAM media and is supported by Windows 98 and many Apple
computers. UDF version 1.5 works with Windows 2000/XP and Windows Server 2003 as
well as Linux systems using kernel version 2.6 or greater. UDF version 2.5 is supported
by Windows 7 and Vista. For Linux kernel 2.6.20 and later support of UDF version 2.5,
install the UDF-2.50 patch available from
http://sourceforge.net
.
Note
By default, Windows 7 and Vista use the LFS (UDF 2.01) to format optical discs. To choose
between LFS and Mastered (copies all files at once; does not support drag-and-drop file
copying), select Show Formatting Options in the Burn a Disc dialog box. To choose a dif-
ferent UDF version, select Show Formatting Options and then Change Version in the Burn a
Disc dialog box.
Note
WindowsXPalsohaslimitedCD-RWsupportintheformofsomethingcalledIMAPI(image
mastering application program interface), which enables data to be temporarily stored on the
