user76810: I understand that a mining pool operator distribute work units at it miners.
Is it possible that a miner can find no share in his work unit?
If is the case, this mean a miner can work for nothing?

user49662: A good pool should manage difficulty levels so that every qualified
1 worker finds at least some share.  It may be a very small share, but something should be counted.
1 By qualified, I mean a processor in the same league as the rest of the pool.  If you join an Intel CPU miner to a pool of ASIC miners, your miner would not be qualified, and it would be appropriate to not get any shares.

76810: <p>I understand that a mining pool operator distribute work units at it miners.</p>

<p>Is it possible that a miner can find no share in his work unit?</p>

<p>If is the case, this mean a miner can work for nothing?</p>
 49662: <p>A good pool should manage difficulty levels so that every <strong><em>qualified</em></strong>
<sup>1</sup> worker finds at least some share.  It may be a very small share, but something should be counted.</p>

<p><sup>1</sup> By qualified, I mean a processor in the same league as the rest of the pool.  If you join an Intel CPU miner to a pool of ASIC miners, your miner would not be qualified, and it would be appropriate to not get any shares.</p>
