Here is the lowdown on a 120GB HD in a m1210.
First Dell uses the HPA (Host Protected Area) for the Media Direct. It is not visable in Disk manager because the HD controller itself lies to the BIOS to hide it. That is between 1.5 and 2.0 GB.
The 55 MB is Dell Utilites.
The ~4.5 GB parition is where dell stores the ghost image (spanned across multiple files) that is used to restore by pressing either fn+f11 or ctr+f11 @ boot (can't remember which).
I removed the HPA (not easy and you can toast a drive) before I rebuild mine the way I wanted. I now have MediaDirect on a visable partition (after calling dell for a MediaDirect Reinstallation CD ... NOT REPAIR). so I see the full ~111.7 GB as expected when considering the Base2 vs. Base10 math issue.
Here is some really good info on DSR and MediaDirect HPA:http://www.goodells.net/dellrestore/mediadirect
BTW: The ramification of the HPA is that Mr.Evil's statement "ABSOLUTELY every single hard drive that is advertised at 120GB will read as only 111.78GB in a disk management utility" is incorrect.
Furthermore the more common usage of the DCO portion of the ATA standard means that there are two ways for a HD to "lie" to the BIOS. HD Mfgs and warranty repair shops use DCOs to replace HDs under warranty. Say that your 40GB drive goes bad, but they only have 80GB in the warranty warehouse. They will apply a DCO so thet the physical 80GB dirve they ship you, is reporting to BIOS exactly like the 40GB drive it replaced.
Here is a great Doc outlining both HPA and DCO:http://polya.computing.dcu.ie/wiki/i..._why_bother%3F
Of course in practice this means all the peeps with m1210 that "scratch" the HD and rebuild the box their own way, are not eliminating the HPA (which still has the MediaDirect image in it), because it still exists, it just is not usable, so they are giving up ~1.5-2.0 GB!