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Gservo
25th August 2002, 02:49 AM
Buffer Underrun Guide


When burning audio-cd's it is absolutely critical that the data-stream from the harddrive to the CD-writer is as continious as possible. The CD-writer has an internal memory-buffer to compensate for small gaps, but if your harddrive or your CPU is interrupted for to long, the CD-writer will run out of data. Because the CD-writer cannot wait, this will cause gaps and noise in the music, or in the worst case, it will ruin the entire disc. Buffer Underrun errors are a common problem when burning CDs.

The source of the problem

So, why is the CPU interrupted? Windows is a multi-tasking operation system, meaning it can run many programs simultaneously. The CPU, however, can only do one thing at a time. To solve this problem, Windows divides the CPU-time into small slices and gives each running program a short period of time to execute, before the CPU is handed over to the next program. The more programs you run, the smaller each time-slice gets. If the slices are to small, there may not be enough time for the burning-software to fill the buffer on the CD-writer.

What about the harddrive? Just like the CPU, the harddrive cannot read everything at the same time. If, for example, some antivirus software or a screensaver starts in the middle of your cd-burning-session, the harddrive may get occupied with other things and stop reading CD-data.

The solution

What can you do to prevent "buffer underrun errors"? There are a few things you should always do before burning audio-CDs:

1. Reboot the computer before you begin to make sure the operating system is completely stable (You never know after running a few games).

2. Terminate all programs but the cd-burning-software. Of course you need WinTasks to be able to stop all the invisible background processes. If you are using WinTasks 4 you only have to do this once, since it is now possible to save the currently running processes and their priorities to a preset. To restore the optimal cd-burning process configuration later, you can simply click the preset button.

3. Don't use your CD-writers maximum burnings speed if you have get any gaps or jumps in the music. If your writer can burn at 4x use 2x, if can handle 8x use 4x and so on. This way, the CPU will only have to send half as much data to keep the buffer full. Making the whole process less sensitive to errors.

4. Try increasing the priority of the CD-burning software. You may have to try a few different settings before you find the optimal priorities for your system. Use WinTasks to change the priorities, and again, I recommend creating preset in WinTasks for the optimal settings once you have figured them out. You should not modify the priorities of the system processes (red), and use the built-in decriptions to find out if what a processes does. (WinTasks 4 have built-in decriptions for most system processes, and many other processes as well.)

5. Always cache to harddrive before burning. (This is usually an option in your burning-software)

As you may have noticed, this guide and many others are available from the "guides toolbar" at the bottom of the WinTasks 4 Standard main window.