Strange targets being produced

[twinklebob]

I'm using pretty old miners, and that may be the cause, but if I connect directly to api.bitcoin.cz I get a target something like 00000000fffffffffff (etc) but if I connect via the proxy I get a target like 00000000ffff0000000000000.... etc.

I left one running overnight and despite running at around 88MH/s (yeah, I know, small fry) it found no matches. That's pretty unusual.

Am I doing something wrong? Do I need to do something to the proxy?

Let me know if there's any more information you need.

[slush0]

Which miner are you using? RPCminer?

[twinklebob]

Yes. During the day I have a (pretty old now) rpc screensaver running every now and then, make the most of those rare minutes I'm away from the screen. I also run another rpc miner overnight occassionally, but I can easily replace that if it's causing the problem.

I haven't found a decent replacement for the screensaver and although it's input is pretty small I like the thought of my downtime earning me a few pennies.

[slush0]

This is known bug of RPCminer; target provided by the stratum proxy is valid difficulty 1, but RPCminer cannot handle it for some reason. There're these solutions:

a) Contact RPCminer developer and ask for fix -> probably the best solution
b) Modify RPCminer and rewrite "target" field in getwork message returned by the proxy to that "compatible" target.
c) Modify Stratum proxy to providing that corrupted, but compatible target to RPCminer.

I don't want to implement c) permanently to Stratum proxy just because other software have bug inside. However the patch of Stratum proxy is pretty straightforward:

Open mining_libs/jobs.py, line 111 looks like:
dif1 = 0x00000000ffff0000000000000000000000000000000000000000000000000000
just change it to
dif1 = 0x00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff

and RPCminer will start working.

[twinklebob]

Thanks for the info.

I agree, you shouldn't rewrite yours to deal with quirks in other applications, that's a slippery slope.

I'll try and contact the dev, but they probably won't support it anymore. And I can't rewrite the RPC miner and since I've got a built version of the proxy I also can't edit that file.

[slush0]

Hi twinklebob,

I just released proxy 1.5.1 which has workaround for RPCminers. Can you please run proxy with --old-target and let me know if it works for you?

Latest binary for Windows is here: https://mining.bitcoin.cz/media/download/mining_proxy.exe

[brown3223]

Hi Slush,

Your fix worked for me. I'm running rpmminer-mod since it seemed to be best suited for CUDA (and I have an Ubuntu CUDA machine in my lab not doing much right now). I used your "line 111" fix above on the older version of the proxy and it worked fine. I then downloaded the new version today and ran it with the --old-target flag and that seems to work fine as well.

I do get an occasional "WARNING proxy getwork_listener._on_submit # [107ms] Share from 'REDACTED' accepted, diff 1" which I don't fully understand, but everything seems to be working for me otherwise.

[slush0]

REJECTED is normal, because rpcminer is quite dumb and it cannot refresh jobs instantly when they reached your computer. I still recommend to update your miner, but I understand that you want to stick with solution which currently works for you.

I'm closing this ticket as it looks that --old-target fixed rpcminer issues.

[twinklebob]

Sorry I missed it, looks like you're happy that it's working though!

[tito]

@slush0 Thanks a lot for fixing it. I wasn't using the stratum proxy cause of this. Now i'll move my workers to your proxy. Thanks 👯