Constantly getting connection interrupted Recenly I started to mine BTC. I'm doing it just out of curiosity rather then for any profit. I compiled cpuminer on my Debian 9 server. I'm trying to connect to the btc.com pool by execuing:

./minerd -a sha256d --url=stratum+tcp://eu.ss.btc.com:1800 --user=myusername --pass=password


I let it run for few hours and didn't get any accepted or rejected shares (not sure about names). Is it normal (I've got some old dual core cpu) or it's because of connection interupts. I'm constantly getting work resets and those connection interupts. Example: 

[2017-11-06 14:04:15] thread 1: 197074856 hashes, 3289 khash/s
[2017-11-06 14:05:15] thread 0: 197233364 hashes, 3285 khash/s
[2017-11-06 14:05:15] thread 1: 197331608 hashes, 3288 khash/s
[2017-11-06 14:06:15] thread 1: 197283568 hashes, 3310 khash/s
[2017-11-06 14:06:15] thread 0: 197093004 hashes, 3264 khash/s
[2017-11-06 14:06:18] Stratum requested work restart
[2017-11-06 14:06:18] thread 0: 8115524 hashes, 3267 khash/s
[2017-11-06 14:06:18] thread 1: 8896012 hashes, 3298 khash/s
[2017-11-06 14:07:17] thread 0: 196031964 hashes, 3278 khash/s
[2017-11-06 14:07:18] thread 1: 197856604 hashes, 3296 khash/s
[2017-11-06 14:08:17] thread 0: 196691096 hashes, 3288 khash/s
[2017-11-06 14:08:18] thread 1: 197740892 hashes, 3286 khash/s
[2017-11-06 14:09:17] thread 0: 197276844 hashes, 3276 khash/s
[2017-11-06 14:09:18] thread 1: 197162844 hashes, 3291 khash/s
[2017-11-06 14:09:37] stratum_recv_line failed
[2017-11-06 14:09:37] Stratum connection interrupted
[2017-11-06 14:09:37] thread 0: 65115504 hashes, 3270 khash/s
[2017-11-06 14:09:37] thread 1: 64935828 hashes, 3307 khash/s
[2017-11-06 14:10:38] thread 1: 198394912 hashes, 3310 khash/s
[2017-11-06 14:10:38] thread 0: 196204988 hashes, 3264 khash/s
I'm doing:

minerd -a scrypt --threads=1 -o stratum+tcp://us.litecoinpool.org:3333 -O ab1jx.4:4


From a script and it works fine.  ab1jx is my username on litecoinpool, worker is 4, password is 4.  Only 1 thread to make it sort of a background process, leave that out to run at full throttle.

I don't get accepted lines often either with cpuminer, I assume because it's so slow.  I do with my ASIC miners.  I see the restarts a lot more often.  Sometimes I get accepted (and a yay) but this is a few orders of magnitude slower than everybody else, so it comes later than everybody else and may get tossed.  Not sure if you still get credited for it.  Check your stats on the pool after an hour or so, that's what counts.

No CPU miner is going to be profitable because it burns more electricity than the coins are worth.  Unless you have free electricity like solar or geothermal.  I do it as a test load on the computer and network.  If it's winter and you heat with electricity anyway it might work out.