What does it mean that a miner can lose its work?

[konradp]

Hi.

I've read entire topic here : https://bitcointalk.org/index.php?topic=108533.0 and I don't quite understand one thing: very often I could read that a miner can "lose their work/shares", for example "Good pools support it (mining.reconnect), so they don't force you to throw away your shares when a disconnect happens"

I thought that as soon as a miner finds a share which is <= share difficulty then it immediately sends it to the pool, so how can it "lose" shares?

[HellDiverUK]

It's not rocket science.  There's a finite time between getting a share, working on it, and then sending it back to the pool.  In that time, if there's a disconnection, then the share is lost. 

[os2sam]

ckolivas has already commented on this.

When you have disconnection and you reconnect, since work isn't tied to difficulty, when you reconnect and submit a unit of work the pool doesn't know what difficulty the work was done at so it doesn't know at what rate to pay for that share.  So it is lost effort.

I think that is the gist anyway.

[konradp]

OK, thanks.

That topic is so long, that sometimes I caught myself reading without fully understanding.