BBC BASIC Programmers' Reference

by Richard Russell, October 2006

If you need to find out the amount of free space on a disk drive you can do that quite easily:

        drive$ = "C:\"
        SYS "GetDiskFreeSpace", drive$, ^SpC%, ^BpS%, ^Free%, ^Total%
        gbytes_total = SpC% * BpS% * Total% / 2^30
        gbytes_free  = SpC% * BpS% * Free% / 2^30

This code fragment sets gbytes_total to the total capacity of the drive and gbytes_free to the free (unused) space on the drive, both in Gigabytes.

If you only want to know the free space as a percentage of the total you don't need to calculate the values in Gbytes but simply use the Free% and Total% values:

        PRINT "The disk has ";INT(100*Free%/Total%+0.5);"% free space"