I saved five files onto a compressed floppy which increased the capacity from 1.38MB to 2.56MB. After I saved each file I went to My Computer>Properties to check the free space. I found that after each file was saved, the capacity diminished each time until the disk was almost full (it wouldn't take another file) and the capacity was just 1.56MB. At that point I had lost 1.0MB of capacity into "thin air". I never had this problem before when saving to a compressed disk.
I then copied the same files onto a another disk with 1.38MB capacity and actually got one more file onto it than I got on the "compressed" disk.
What caused this and what can be done to correct the problem?