If you're using the Live File System format, you don't need to allocate any additional space to burn your disc, since each file is written to the disc as you go.
If you are creating a Mastered disc, however, Windows needs to create a complete "image" of the disc before it is burned. This disc image can be as large as the maximum capacity of the disc you are creating—you might need 650 megabytes (MB) on your hard disk to create a CD-R, or 4.7 gigabytes (GB) to create a DVD-R.
Yes, if you have more than one hard disk installed in your computer, you can specify which disk is used to create your disc image. Here's how:
1. Open Computer by clicking the Start button
2. Right-click the drive that is your disc burner, and then click Properties.
3. Click the Recording tab, and then click your desired drive from the drive menu.