Checking Disk Vitals
Once the disk is mounted, you can check several important flash disk parameters:
Fd.capacity will tell you the number of usable data sectors on the disk (this excludes housekeeping sectors maintained by the disk).
Fd.totalsize will indicate how many sectors the disk occupies in the flash memory. Fd.totalsize=fd.capacity+fd.numservicesectors.
Fd.getfreespace method will return the number of free data sectors on the disk (those not yet occupied for file data storage).
Fd.getnumfiles fetches the number of files currently stored on the disk.
Keep in mind that currently existing disk might not be the largest one that could fit in the current data area (fd.availableflashspace).