[bblost]

Imagine this.
2 buckets, one bucket holds 20 liters and its is full.
The other bucket can only hold 100 ml at a time.
You have a mug that can take 1/2 liter at a time.

The small bucket has a leak and looses water at 10 ml a second.

so when you want to transfer water, you will move 100 ml from bucket 1 to bucket 2 every 10 seconds.

Now suppose you have a big bucket 3, that can hold 30 Liters.
You can move the water 1/2 ll at a time and finish it off in just 40 moves.

now replace
bucket 1 is your pen drive
bucket 2 is your HU
bucket is a PC.