[douglas]

That 8 MB of unpartitioned space is actually where the information on what partitions you have and what parts of the disk they are on is stored. No, it almost certainly doesn't actually require the whole 8 MB to store that information, that's just the smallest section of hard drive space it can allocate, just like a program requesting one extra byte of RAM is probably going to get a 4 KB chunk (which further requests will use until it's all gone) instead. Keeping track of space in units much smaller than that would require too much extra space dedicated to keeping track of it than the extra precision is likely to be worth.