I have always been surprised why there is 8MB of disk space that cannot be used when partitioning Windows XP. I have repeatedly partitioned the hard disk many times because of this problem. It turns out that this 8MB is used when WinXP retains basic disks and transfers them to dynamic disks. Now that the disk is so big, you can completely ignore it. If you really don't like it, you can use a partitioning tool such as PQ.

Hard disk partitioning is also a problem. Whether it is divided as 1GB=1000MB or 1GB=1024MB, it will become a decimal number after it is divided, such as 19.5G. For some perfectionists, it's really intolerable. To think about an integer partition such as 30G, we need to do a calculation in advance. The formula is Y=(X-1)4+ 1024X, where X is the integer partition value we want to get, in GB. Y is the value that needs to be entered for the partition, and the unit is MB. For example, 30GB is (30-1)4+102430=30856.
The following table shows the partial partition sizes and corresponding values.

10GB (10-1)4+102410=10276
15GB (15-1)4+102415=15416
20GB (20-1)4+102420=20556
30GB (30-1)4+102430=30856
40GB (40-1)4+102440=41116