calculation sizes question

[naxo]

Hi

Anyone knows how to calculate drive, file or folder sizes when converting to another size measures? I mean:

bytes to megabytes
megabytes to gigabytes
gigabytes to Terabytes

Second question:
If you were installing somethin to hdd how do you calculate the "remaining minutes to finish install" thing into suf or ams? I read in help ams the copy function callback but how to adapt the time to finish install part into that callback?

Thanks