The next level is that some flash drives reserve some of the space as a hot failover as memory cells die. Some have this separate from the advertised memory capacity, whereas others may report the total memory on the device even if it’s not available for direct use by the user.
So a double whammy of GB vs GiB and reserve flash memory to keep the drive going as cells die.
True, and adding the filesystem also takes off somewhat. That, however, doesn’t explain 15 vs 9 gb
The next level is that some flash drives reserve some of the space as a hot failover as memory cells die. Some have this separate from the advertised memory capacity, whereas others may report the total memory on the device even if it’s not available for direct use by the user.
So a double whammy of GB vs GiB and reserve flash memory to keep the drive going as cells die.