One of the great mysteries of PC audio is why some systems seem to be able to
consistently 'burn' glitch-free audio CDs while some faster systems routinely
spit out useless 'coasters'. The answer is often that PCs are typically
configured for performing home office tasks such as receiving faxes,
automatically receiving e-mail or Internet 'chat' messages, or automatically
running anti-virus scans at preset intervals. 

Since Windows 9x is not the best at "multi-tasking", these "background tasks"
can interrupt processes you may be working on at any given moment. If a
background task interrupts you typing an e-mail message or a document in your
word processor, you can afford to simply wait for a split-second until the
system becomes available again. However, if you were burning a CD-Recordable
disk, the background task might have interrupted the CD burning long enough 
to cause it to fail. How can this happen? 


I) CD Burning Requires Steady Throughput
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The CD-Recordable drive ("CD-R drive") has a data buffer to store incoming
data just before it gets burned onto the CD-R disc being recorded. During 
the process of burning a CD-R this buffer is constantly being drained of data
while simultaneously being replenished with new data from the hard drive(s). 
As long as data flows in a steady stream from the hard drive(s) to the CD-R 
drive's buffer, all will go smoothly. 


II) The Dreaded "Buffer Under-run"
-----------------------------------
If the CD-R drive's buffer should ever be drained to empty, the CD-R drive
will suddenly find itself unable to write data to the CD-R disk.
Unfortunately, the CD-R drive is not smart enough to stop and wait for more
data; it simply fails the disk writing operation and displays a 
        "buffer under-run" message, 
then aborts the entire disk-write operation and spits out a useless "coaster"
(an unreadable CD). 

NOTE 1:
-------
Older CD-R drives had very small buffers, some as small as 256kB. Most
recently manufactured CD-R and CD-ReWritable (CD-RW) drives are equipped 
with an extra-large buffer, typically 2 to 8MB (up to almost 40X bigger). 
This extra buffer memory greatly minimizes the chance of a buffer under-run
occurring. If you are having problems burning CDs with an older CD-R drive, 
it may be easiest to simply upgrade to a newer model. 

NOTE 2:
-------
If your hard drive is nearly full, the data being burned onto a CD-R disk will
likely be located in small areas spread out all over the hard drive (the data
on the hard drive will be "fragmented"). During a CD burn, it may take so long
for the drive head to find the data that a buffer under-run can occur. Always
make sure you have plenty of room on your hard drive(s)!


III) Optimizing the System for CD Burning
---------------------------------------
A) Check in the Windows Control Panel (Start > Settings > Control Panel) 
   System > Performance tab > File Performance, that your hard drive(s) 
   and/or CD-ROM drive(s) are not running in "MS-DOS Compatibility Mode".
   If they are, it means the proper drivers are not installed for the Hard 
   Disk Controller on your motherboard. CD-R burning will not work properly
   from drives that are operating in "MS-DOS Compatibility Mode". You will 
   need to fix this problem before proceeding. Please contact the appropriate
   service personnel for your PC system for assistance. 

B) In Windows 95/98, it's best to turn off (disable) all background 
   processes such as:
    - Task Scheduler
    - Auto-Insert Notification
    - Anti-Virus programs
    - Fax Notification programs
    - Network Connections
    - Internet Connections
    - ICQ or AOL Instant Messenger
    - Complex system optimizers such as Norton Utilities, etc. 

C) Use two partitions on your hard drive (or two separate hard drives) 
   —one (C:) for the operating system and programs, and a second (D:) 
   for the data being burned onto CD-R disk. 

D) If your system has an older, slower hard drive, or your hard drive is
   nearly full, consider adding a second hard drive for the data being 
   burned onto CD-R. Recently manufactured ATA-66 and ATA-100 hard drives
   are less expensive, much bigger and much faster than UltraDMA and 
   E-IDE drives made as recently as two years ago. 

E) Always defragment the hard drive that holds the files you will be burning
   onto a CD-R disk, before you start the recording. Either Windows Defrag
   or Norton SpeedDisk will do the job. 

F) If all else fails, add a section titled [VCACHE] to the 
   C:\Windows\System.ini file. Then add these two lines:

      MaxFileCache=16384
      MinFileCache=16384

   You can try different size cache settings, from 2048 to 65536. 

G) For maximum results, use an UltraWide, Ultra2 or LVD SCSI hard drive to 
   store the data and a SCSI CD-R drive for burning your CDs. Use an 
   UltraWide or Ultra2 (LVD) SCSI host controller PCI card. 

H) FireWire and USB CD-RW drives have recently been released, but it is too
   early to tell if these are working well in typical PC configurations. 


See also the article: 
"Troubleshooting tips for improved digital audio performance"


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