add some of @raulk's notes.

notes/raulk.md

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+# Raúl's notes
+
+## Storage mining
+
+The Storage Mining System is the part of the Filecoin Protocol that deals with
+storing Client’s data, producing proof artifacts that demonstrate correct
+storage behavior, and managing the work involved.
+
+## Preseals
+
+In the Filecoin consensus protocol, the miners' probability of being eligible
+to mine a block in a given epoch is directly correlated with their power in the
+network. This creates a chicken-and-egg problem at genesis. Since there are no
+miners, there is no power in the network, therefore no miner is eligible to mine
+and advance the chain.
+
+Preseals are sealed sectors that are blessed at genesis, thus conferring
+their miners the possibility to win round elections and successfully mine a
+block. Without preseals, the chain would be dead on arrival.
+
+Preseals work with fauxrep and faux sealing, which are special-case
+implementations of PoRep and the sealing logic that do not depend on slow
+sealing.
+
+### Not implemented things
+
+**Sector Resealing:** Miners should be able to ’re-seal’ sectors, to allow them
+to take a set of sectors with mostly expired pieces, and combine the
+not-yet-expired pieces into a single (or multiple) sectors.
+
+**Sector Transfer:** Miners should be able to re-delegate the responsibility of
+storing data to another miner. This is tricky for many reasons, and will not be
+implemented in the initial release of Filecoin, but could provide interesting
+capabilities down the road.
+
+## Catch-up/rush mining
+
+In catch-up or rush mining, miners make up for chain history that does not
+exist. It's a recovery/healing procedure. The chain runs at at constant
+25 second epoch time. When in the network mining halts for some reason
+(consensus/liveness bug, drand availability issues, etc.), upon a restart miners
+will go and backfill the chain history by mining backdated blocks in
+the appropriate timestamps.
+   
+There are a few things worth highlighting:
+   * mining runs in a hot loop, and there is no time for miners to gossip about
+     their blocks; therefore they end up building the chain solo, as they can't
+     incorprate other blocks into tipsets.
+   * the miner with most power will mine most blocks.
+   * presumably, as many forks in the network will appear as miners who mined a
+     block + a fork filled with null rounds only (for miners that didn't win a
+     round).
+   * at the end of the catch-up, the heaviest fork will win the race, and it may
+     be possible for the most powerful miner pre-disruption to affect the
+     outcome by choosing the messages that go in their blocks.