All this is covered in the official Avalon 821 and 841 threads...
Never used something like GIT I take it? Use the link "Parent Directory" a few times and you get to Index of /downloads/software/
Navigate down from there.

...snip...

Controller Green - good, Miners should be Blue though.  Did you burn 841 firmware for the Pi?

...snip..
Are you using the same controller (PI) The 841's have a different controller firmware that needs to be flashed onto the PI.

Also if you do have that set properly, did you try switching the cables around you are using to Daisy Chain them, it might be that the first one in the chain is defective. This was just a guess because I don't think the miner lights would be green if this was the case. EDIt: Got my colours switched up might be the cable since this is "idle"

So, I felt the urge to ramble on about Bitcoin again since this block is pissing me off probably as much as everyone else here

Rather than try to edit in and out of the various posts ... here's how mining works

Firstly, mining is exactly the same as rolling a dice ... except for the number of possible solutions!
When you roll a dice, you have a 1 in 6 chance of getting a 6.
There's no progress to getting a 6, ever. You either get a 6 or you don't.
One try = yes or no. No history involved.

With Bitcoin the dice actually has 2^256 sides - yeah that's a pretty big number ~1.579x10^77
And ... there's more than one solution that's valid.
Any "side of the dice" that has enough zeros on the front, and is less than a specified value, is a block.
Of that ~1.579x10^77 number, the current difficulty decides how many sides mean we found a block.

The current difficulty is actually "0x176c2146" which is called "bits" and is 4 bytes of the data we hash.
"0x17" = 23 decimal and 32-23 = 9 bytes of leading zeros (i.e. 9 times '00')
The rest is "0x6c2146"
So, what those 2 numbers mean is that any block hash with a hex value of
H=0x0000000000000000006c21460000000000000000000000000000000000000000 or less is a block

and if you divide 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff+1 (~1.579x10^77) by H and divide it again by 0x100000000 (2^32) you will get that network difficulty number:
Nd = 2,603,077,300,218.593
which means that every 2^32 times you roll the Bitcoin dice (i.e. hash a full nonce range) you have a 1 in 2,603,077,300,218.593 chance of finding a block.

... and the reason we divide by 0x100000000 again is that the network difficulty number of 1 represents 2^32 hashes

So ... that's how hashing works, but what are we actually hashing?

I wrote a document about it once, I'll repeat a little bit here:

The structure of a block header is an 80 byte binary data set, defined as follows:
Version                   4 bytes
Previous Block Hash      32 bytes
Merkle Root              32 bytes
Block Time                4 byte Unix Timestamp
Required Hash Difficulty  4 bytes
Hash Nonce                4 bytes

So looking at that we can vary 3 things:
Merkle root, Block Time and Hash Nonce

Normal hashing is to setup everything except the Hash Nonce and then count the Hash Nonce from 0 to 2^32-1 and hash each one.
Hashing the full Nonce range from 0 to 2^32-1 is also called 1 difficulty.

With stratum we can modify the Merkle Root to generate a different block header to hash the Nonce range.
The Merkle Root is a hash tree of the transactions we include in the block, however there's one transaction that we can change with stratum, and that is the coinbase transaction - or the transaction that pays the miner.
In this transaction we only need to make sure that:
1) It's a valid transaction (which is actually pretty random for the coinbase transaction due to the "sig" being allowed to contain almost anything as long as it starts with 'height')
2) It pays out to the expected address we want to receive the generated Bitcoins
3) The amount it pays is correct

So for stratum we put a bunch of other 'nonces' in the coinbase sig, that includes a unique number for each miner, and run the others from 0 up to some specified limit to generate a different coinbase transaction each time, that will generate a unique Merkle Root, to be put in a block header, to be hashed over the full Nonce range.

Thus with the unique number for each miner, and the miner itself following the stratum rules for creating coinbase transactions, the miner can keep generating a large amount of work that isn't expected to run out before the pool sends it new work.

Lastly, every time the miner finds a hash value that is higher than the difficulty specified by the pool, the miner sends the nonce and the "sig" nonces back to the pool.
The pool hashes those nonces with the values it sent to the miner, and thus verifies it's valid, and thus rewards the miner with the difficulty of the work sent to  the miner.

Now one more thing I'll add, that got mention a little while back, is that the miner can't modify the payout address to 'steal' the block.
The reason is that the pool wont get a valid hash of the nonces sent back, so the miner will get no reward. Simple

Yes, this block for us, as in the next block the we finally solve,  but we've been working on lots of different network blocks since we cracked our last one. We'll all still use the "this block" expression though because it is convenient for our discussion purposes. That said........Let's crack this block!  

Edit: And of course, at any point in time, the block we are trying to solve is "this block". It's just that "this block" is a group of different blocks since our last one. Ok, I think this horse is dead so I'll stop beating it.  

4876 people trying to simultaneously buy less than 200 units.  cart just has problems on the last few, its millliseconds between stock removal and addition for the last few.  It is not that it is getting pulled from your cart, the front end caching is not caught up with the backend and it was not available to begin with.  If you can replicate a way to have 4000 people checkout at the same time on three different browsers, send us a resume.  But for the few that emailed us saying they had problems and didnt tell us to eat a d**k we took care of them.

Here's the thing people. Stop complaining; 

Unlike every other company out they go out of there way to list any extra units that become available for forum members. They even carve out a small slice for us from the main order.

It does suck when you try and can't get through or you happen to get there to late. I'm sure they will try and fix it, but really if you get to the end and it says out of stock, take a minute breathe, and then act like you just got there and there were none available.

If people keep shitting on their efforts where is the incentive for them to come here and give us a shot at units, and even a slight discount sometimes.

It's been showing that nothing is profitable like that since I started mining with only a hammer and chisel

It's all speculation.

Thanks, now, how do you do that, with mycelium?

They haven't updated the iOS version yet? Latest android version allows fees so low the txn can get stuck.  How do I know that you ask?  

I was waiting for the Canaan A8's but at 4K a pop? Wow, that is hard to justify. Currently at 56TH/s with 4 S9's at 14TH/s each. I paid ~7.5K +/- for the miners (bought when they were $1,320 ea), power supplies and PDU's. To get the comparable hash with Canaan is ~23K +/- for the miners, power supplies and PDU's. I love the fact that Canaan is a competitor but WOW, paying 3 times the cost is very hard to justify for less hash rate. Did these miners use gold hashing boards?

Others thoughts?