Blu-Ray and Drives

[pablops]

I poked around the forums a while and couldn't find answers to my questions, so would appreciate input on this:
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When I bought the Dell MultiMedia machine I'm using for HD, I found that the drive wouldn't write AVCHD disks. It took a long time and much experimentation but finally after 3 drives from Dell I bought one off the web that would write AVCHD successfully. QUESTIONS:

1 - Generically speaking will a drive that writes AVCHD possibly also write Blu-Ray format? Is there a difference? Or do I need a specific drive to write Blu-Ray disks?

2 - I noted in the software I'm using (Corel's Ulead 11+) that if I choose "Blu-Ray" instead of "AVCHD" that it asks for different medie - i.e., a "BD-R" disc and I'm wondering if that means a new drive or different drive? I have written AVCHD discs that I shot with my Sony SR1 in HD that play fine on my Blu-Ray player, but obviously that doesn't mean I understand all the nuances. (I guess this is basically the same question but from a slightly different point of view.)