k, here is how dynamic works. Say you have two HDD. HDD 0 and 1 (as the disk manager sees it). HDD 0 is 40GB and HDD1 is 80GB. Now, you can take HDD 0 and HDD 1 and convert them both to Dynamic and you will NOT lose any data (starts as a 'Basic' volume and converts to a 'Dynamic' volume. Now, say you want the remaining 8GB left on HDD 0 and want to combine that with HDD 1, which is empty. All you do is right click on the unallocated space and click on create volume and what you wanna do is "Span", or extend the volume. Now you have drive C: which is 32GB of HDD 0 and a drive D
or whatever) which is a total of 88GB (8GB from HDD 0 + 80GB of HDD 1). No problem there. Here are the limitations, though...
1. Data that was on originally written to a Basic HDD can NOT be spanned, can be made dynamic, but not spanned. Now, if you got your HDD, changed it to Dynamic, wrote data to it and later decided to span this HDD then you could because it was originally written to a Dynamic disk, but not from data written while it was in its 'Basic' volume structure.
2. The system volume can NOT be spanned, because of the boot/file structure. A spanned volume doesn't use a MBR, instead it uses its own file system (hence the reason basic HDD info wont convert to a spanned volume). Now, if you had taken the HDD and began it as a dynamic volume, no biggie (save the system section, it doesn't count).
3. When doing a spanned/extended volume, it usually wants you to perform a format (it assumes you have a fresh drive to combine to what is left over from a previous drive), but you dont have to do this. If you already have a Dynamic array, than I suggest backing up data before trying this, as it doesn't always work out the way you want and data corruption can happen, hell I wouldn't be surprised if it happened often. Anyhow, thats a rough (and probably hard to follow) overview on spanned dynamic disks.