CHAPTER 13

758 Chapter 13 Optical Storage
data), it temporarily suspends the recording until more data fills the buffer. When the buffer is sufficiently
restocked, the drive then locates exactly where the recording left off earlier and restarts recording
again immediately after that position.
According to the Orange Book specification, gaps between data in a CD recording must not be more
than 100 milliseconds in length. The buffer underrun technology can restart the recording with a gap
of 40–45 milliseconds or less from where it left off, which is well within the specification. These small
gaps are easily compensated for by the error correction built into the recording, so no data is lost.
Note that it is important that the drive incorporate buffer underrun technology, but the recording
software must support it as well for everything to work properly. Fortunately, all the popular CD
recording programs on the market now support this technology.
If your drive incorporates buffer underrun protection, you can multitask—do other things while burning
CDs—without fear of producing a bad recording.
Producing Error-Free Recordings
If you have an older drive that doesn’t feature buffer underrun protection, follow these recommendations
to help ensure error-free recordings and prevent buffer underruns:
■ Whenever possible, move all data you want to put onto a CD-R to a fast local hard drive. If you can’t
do this, avoid using the following sources for data: floppy drives, parallel port–connected storage
drives, and slower CD-ROM drives (especially 8x or slower). These locations for data usually
can’t feed data quickly enough to maintain data flow to the recording drive.
■ Before you master the CD-R, check your hard disk or data source for errors (the scandisk program can
often be used for this). Also try defragmenting the drive. This ensures that disk errors or file fragmentation,
both of which slow down disk access, won’t be a factor in program or data search
and retrieval.
■ Avoid trying to burn from active files or zero-byte files (often used for temporary storage). If you must
burn these files to make an archival copy of your current system configuration, use a program
such as Norton Ghost or PowerQuest Drive Image. These programs create a single compressed
file from your drive’s contents. Then, burn the disc using the resulting compressed file.
■ Turn off power management for your hard disk and other peripherals. You can normally do this
through the Power icon in Windows 9x.
■ Make sure your temporary drive has at least twice the empty space of your finished CD. Your CD’s estimated
space requirements are shown during the mastering process with programs such as Roxio
Easy CD-Creator or NERO Burning ROM. Thus, if you’re creating a CD with 500MB of data,
your temporary drive should have at least 1GB of empty space.
■ With Windows 9x, you’ll improve disk caching by adjusting the typical role of the computer from workstation
to server in the Performance tab of the System Properties dialog box. Note that this change
works correctly with Windows 95B and 95C (OSR 2.x) and Windows 98/Me, but the Registry
keys are incorrect in Windows 95 original retail and OSR1 (95A) versions. Check Microsoft’s
Web site for the correct Registry key settings for Windows 95/95A, back up and edit the
Registry, and restart the computer before making this change with those versions.
■ If your original data is coming from a variety of sources, consider using the Create Disk Image option
found in most CD mastering software. This feature creates an image file on your hard drive that
contains all the files you want to put onto a CD. Then, use Create CD from Disk Image to actually
master the CD from that information.
■ If you’re uncertain of success, why waste a CD-R blank? Use a CD-RW instead, which usually is
written at a slower speed, or use the “test-then-create” option found in most recording software