Thats called Proof of Work (PoW).
But there is also a System called Proof of Stake (PoS).
The transaction confirmations are not done with hardware but with already owned coins.
An amount of your coins are on the stake, while they are used for staking. That depends a little on the implementation.
But basically you get a certain percentage of your coins as a reward.
Some people think, they can "earn" here, but that's nonsence, because if the market cap stays stable, the single coins are worth less, if new coins are generated. So you just "keep" your value, if you are staking. And "loose", if you are not...
Its like in a bank if you get 2% interest and the inflation is 2% as well.
You only "earn", if there are transaction fees and if those are also payed to the staker.
There are also similar coins that don't use "staking". They use for example "forging" (NXT) or "harvesting" (NEM), what is also based on the coin stack, but they don't create coins and only get the transaction fees.
There are also coins, that combine PoW and PoS. In general there are 3 possible ways:
1. Only PoS coins, that are "premined" and just sold in an IPO (NXT, NEM)
2. Use of PoW and PoS hybrid (Peercoin)
3. Use of PoW only as a distribution method until a certain time and then use only PoW (Blackcoin, Bitz)
I think its a matter of taste, what is better. I personally like the 1. and 3. option the most.
locking thread