Onboard Music Collection Q

[ABMW]

I just read the onboard music collection can store 16,000 songs. I wonder why BMW doesn't even promote this in their materials.

My question: how is this stored? Is it in solid state or in a hard drive?

I understand one must connect a USB flash drive or other solid state device filled with songs to transfer over your music.

Has anyone performed such a sync using their notebook computer or iPod?

It's kind of neat, but getting 16,000 songs onto a thumb drive and then transferring them over, sounds interesting, at best.