I'm using EASEUS Partition Master Home Edition to create a single Logical partition on a WD10EARS-00Y5B1 1TB HDD. After wiping the disk completely, and selecting to create a single NTFS partition, I note that there is a 7.8MB unallocated space at the front of the disk (see image).
Can someone explain what this space is, and why it is unallocated?
Need just a little explanation here about disk theory.
A "logical" partition is defined inside of what's called an "extended partition", which is a special purpose "primary" partition inside of which one or more "logical" partitions can be sub-defined.
A basic MBR hard drive can support up to four primary partitions, and any one of them can be used as an "extended" partition so that one or more "logical" partitions can be sub-defined inside of it.
So you can have three real "primary" partitions, and one "extended" partition inside of which any number of "logical" partitions can then be sub-defined. Of course you can also have ZERO real "primary" partitions and just one "extended" partition on your drive (as you've done), so that all partitions defined on that drive are "logical" and located within the one single "extended" partition.
The "extended" partition has some control information (think of it as sort of a "prefix") which lives outside of real data area that's used by the "logical" partitions inside of it. This "prefix" isn't very large, but needs to exist. Since space allocation on a drive is in sector group units of 8MB, just one 8MB allocation unit is sufficient to hold the "prefix" information associated with the "extended" partition. But once it's been partially consumed for that purpose, the remainder of that 8MB is unavailable for further allocation since space allocation is in complete 8MB units.
===>> That's why you see 7.8MB "unallocated", because .2MB of that 8MB unit of space has been used for the "prefix" information tied to the one "extended" partition inside of which your "logical" partitions live.
Don't worry about it. That's perfectly normal and by design. You will not be able to make use of this 7.8MB for any purpose.