strange problem in partitioning new 320gb harddisk.....

[tango_cash]

hi people my config is 2.8 intel p4 h.t, 915gav intel mobo,1.5gb ram, 250gb hdd segate.
i have bought a new segate 320gb hdd. now i want to install os on it .
so i made partitions in it .
i made 30gb 100gb 100gb and 68gb partitions in it. but there is a strange problem.

in the disk management when i make a partition for 100gb i enter 102400(100*1024)
it makes a partition of exactly 100gb as it shows this in the disk management but in my computer it shows 99.9gb and free space also of 99.9gb.see the partition M in both the images below.

but when i make a partition of 100gb as 102408(100*1024=102400+8=102408
then in the disk management it shows 100.1gb and in my computer it shows 100gb exact. but it shows 99.9gb free space. see the partition N in both the images below.why is this happening???

why is this hapening i just want 2 partitions of 100gb and with all 100gb free space.how do i do it.

here is the screen of my computer
and this one is of the disk management http://img49.imageshack.us/my.php?image=123ch0.jpg

[ravi_9793]

some space is taken by OS..for disk management.

[tango_cash]

i understand that but what i dont understand is why is it showing diffrent "free space" in my computer.
jab M partition mein woh 99.9gb total space dikha raha hai aur free space bhi 99.9gb dikha raha hai, to phir 100gb wale N partition mein 99.9gb hee free space kyu dikha raha hai???

some space is taken by OS..for disk management.

kya os ko M partition mein some space nahi chahiye?? sirf N mein he chahiye kya??





arey meine iska solution nikal liya
see
and

i just made partition of little more than 100gb i.e 100.1gb=102502mb that way xp can take some space it always needs to take and still in the my computer it shows 100 gb as total disk space and 100gb as free space.

[tango_cash]

but look at my older drives partitions C E and G partition they are of 20gb 80gb and 10gb respectively and they show exactly the same size in disk management and my computer.
why is that????