APPENDIX C
Tips
1. What does "buffer underrun" mean?
The CD writing process can't be interrupted in mid-session. To prevent this from happening, the
makers of CD recorders put a write buffer in the drive, usually 512K or 1MB. Data read from the
hard drive, tape, or another CD is stored in the buffer, and pulled out as needed by the recorder.
If the recorder requests data from the write buffer, but there's none there, it's called a buffer
underrun. The disc is still spinning, but
there's no data to write, so the recording process aborts.
2. How to prevent " buffer underrun"?
A brief summary:
•
Use a fast hard drive.
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Record at a slow speed - it takes longer to empty the buffer when recording at 1x.
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Don't do anything else with the computer while recording. Don't record from a file server.
•
Defragment your HD, especially if you're doing on-the-fly recording.
•
Record from an ISO image file rather than on-the-fly.
•
Depending on your setup, putting the recorder and your hard drive on separate SCSI
controllers may be necessary.
•
Keep your CD-R cool. Sometimes the drives fail when they overheat.
•
Keep CD-Rewiter read/write head cleaning.
•
Also watch out for things like anti-virus programs that wake up, virtual memory settings that
cause swapping, screen savers that activate during the CD creation process, unusual network
activity, and background downloads of data or faxes.
•
Stabilize Your System for CD-R.
•
Shut Down Other Applications.
•
Test before writing.
•
Another important tip for Win95 is to limit the size of the file cache, which by default is
unrestricted. The procedure is simple:
1. Open the file SYSTEM.INI with a text editor. This file is usually C:\WINDOWS\SYSTEM.INI.
2. Find the section labeled "[vcache]".
3. Add the following lines *after* the "[vcache]" line:
MinFileCache = 512
MaxFileCache = 4096
4. Save the changes to the file, and reboot.
3. Should I turn off Auto Insert Notificaton ?
Most Win95-based recording software recommend turning off Auto Insert Notification. Having this
on can interfere with closing sessions or even just inserting discs into the drive. You can disable it by
opening the "System" icon in the Control Panel, and selecting "Device Manager". For each item
under CD-ROM, select the device, click on the "Settings" tab, and make sure the "Auto Insert
Notification" checkbox is unchecked. (Some programs requires that the auto insertion be turned on.)
If you're using WinNT, you can turn it off with the "TweakUI" program available in PowerToys, or by
modifying a registry key with
Regedit32
(0=disabled, 1=enabled):
HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \
Cdrom \ Autorun
The trouble with Auto Insert Notification is that it periodically attempts to find a valid disc in the CD
recorder. A blank disc isn't very interesting to Windows, so nothing happens. When the table of
contents is written to the disc, it suddenly becomes interesting, and enough activity is generated by
Windows' attempts to read the disc that the write fails.
4. I can't read the multi-session CD I just made
One possible cause of this problem is writing a multisession disc in MODE-1 format. Some older
CD-ROM drives incorrectly assume that a MODE-1 disc can't be multi-session, so they don't look
for additional sessions unless it's written in MODE-2 (CD-ROM) format.
Also, if the final session on the CD isn't closed, standard CD players may become confused. This
doesn't mean that the *disc* must be closed, just that the *session* must be closed.
5. Write process keeps failing N minutes in
There's a couple of possibilities. One is that your data source can't keep up with the CD-R; try using
disc-at-once writing from an ISO image with the speed set to 1x. If it seems to be getting worse over
time, you may just need to defragment your hard drive.
If that fails, a number of people have discovered that the problem is a faulty CD-R unit, which have
different mechanisms. You should try 1x writing from a fast source and with different sets of data.
Be sure that there aren't environmental factors creating difficulties. CD-R units are usually built to
handle small shocks, but having a set of speakers playing loud music on the same table as a CD-R
may cause it to skip, resulting in a failed write. Sonic booms, heavy construction equipment, and
nuclear detonations may have similar effects.
