It is impossible to make it CPU ONLY mineable. The way to keep GPU miners out is to make it unprofitable for them. My suggestion is to award the coins not to the first solution presented, but to a random solution solver. Instead of increasing the difficulty level each block, increase the number of solutions that must be presented before the award.
No matter how difficult the block, a GPU will always out perform a CPU. If you were into computers in the 80s and early 90s, you would remember how long is took a CPU to load an image. You could actually see the image load, line by line. A 480x600 image in color, could take over a minute to load. When Graphic cards came out, even the early 500k cards, the images loaded in a second or two.
If the award goes to the 20th or 50th solution, randomly, the GPU miners will find it unprofitable. When a new block is released for hashing, the GPU miners will solve it very quickly, and submit the solution.... while the CPU miners will eventually solve it, but lag behind. The pools will likely be the first to submit, solo GPU miners second, and CPU miners third. Awarding coins to the 20th solution will increase the chances that a solo CPU miner gets the coins, and not a pool or a GPU miner.
There are plenty of coins for GPU and pools to mine. It would be beneficial to the popularity of mining, if a coin, or two, was set up to largly favor CPU miners.... the average joe with a laptop.
Thanks for your suggestions.. as an "average joe on a laptop" I really do agree!
I think adjusting a reward system to reward not first but a randomly selected solution would still prove ineffectual. As the percentages of people submitting those would be determined simply by who's mining.. so if say there are 2 cpu miners and 1 GPU miner, the GPU miner would simply be re-doing that block and still get a better odds than either of the CPU guys.
I would sincerely love to see more CPU miners (botnets be damned, I want my mum to be able to mine even just for a slice).. To make STCY CPU only I'd need to rework the coin against quark or primecoin.
Its all appealing as I am only a CPU miner myself but I need to try and keep this project to its goals.
That is:
- no pre-mine etc
- Code is strictly downstream of MAX. which means GPUs will be mining from the get go (Shikata ga nai)
- A really fabulous launch (this is where most of the work will be going)
I'm currently trying to get the maxcoin-qt client fixed but won't stay too obsessed on it.
No launch date announced yet but good progress has been made, a test genesis booted etc..
Currently establishing relations with trusted pools, website + docs being developed
I'm planning to do some node tests this week (possibly tonight) and test+document deployment of STCY pools and 1gh's cpuminerd and Ahmeds stratum code.
Maybe once STCY is in the wild and stuff we can look a keccak enabled CPU coin, I suspect its already been done actually but haven’t the time to segway there yet. My workstation currently mining SRC for what its worth, not got the time to investigate others
... then again.. maybe STCY should be a CPU only clone.. I'll propose the question on twitter to see what reaction I get (at least that way I wouldn't need/want to fix the miner in the -qt wallet)