As codehalo pointed out, there's no magnetic pattern that represents coins on your hard drive. There is a magnetic pattern that represents your private key for

As codehalo pointed out, there's no magnetic pattern that represents coins on your hard drive. There is a magnetic pattern that represents your private key for your wallet (if you store it there), which possession of you might equate to possession of the coins to since without it they can't be used. Still, access isn't really possession is it. I can lend my house key to a friend but they don't possess my house. The deed is what really declares me the owner. In the case of your coins, it's the consensus of the blockchain.