The total size needs to have 3 factors cylinders, heads, & sectors. Imagine a disk having a total size with 3 prime factors 3 x 5 x 11. 15 cannot be assigned to heads because that would only leave 11 for sectors and cylinders. Therefore, test all heads and sectors combinations. If the third factor for cylinders is not found, then choose 16 heads, then the minimum number of sectors, and finally the maximum number of cylinders. The loop could be changed to skip values of heads that are not a factor, but it doesn't take any time to try them all.
Allows different implementations for different platforms (the JS
build relies on browser APIs to stream disk images over the network).
Setting aside the JS build, this also reduces some code duplication.
