Vertcoin difficulty more than doubled in a couple of days,
it looks like ASICs or FPGAs may have arrived for lyra2v3.

There have been a large number of scam miner programs being posted here recently.

They are always closed source and only avaiable as binary files for Windows.
Crypto miners are the vehicle for the malware because they are known to generate
false positives by AV scanners and inexperienced users ignore the alert thinking
it's just another false positive.

Their ANN post tries to look legitimate, often copying text word for word from other miners ANNs.
They may post change logs to make it look like they have a history.
They may create github repositories with no source code, sometimes even claiming to be open source
with fake links that Windows users would never test.

They often target other newbies with claims of being easier to use.

There are a few clues to detect them:

Always posted by a newbie user.

Always closed source with only Windows binaries avaiable to download.

Slick ANN post with sprinklings of technical info often copied from others.

Real devs have credentials that can be verified: posting history, other work, testimonials from
trusted users, etc.

There have been several of these malware posts in the last week.

Any offer from a newbie user, especially closed source, should be taken with a healthy dose of
skepticism.

Stay alert and stay safe.

I'm an altcoin guy but this question applies to bitcoin.

The formula for converting share difficulty to an equivalent number of hashes
is documented on the bitcoin wiki: https://en.bitcoin.it/wiki/Difficulty

However, in my testing this formula produced incorrect results for altcoin algos.
I couldn't test sha256d as I don't have HW capable of supporting the extremely
high stratum diff. But since most altcoins were cloned from bitcoin I see no reason
why sha256d/bitcoin would be an exception.

Following are the comments I added to my code to explain my modification.
I arrived at the value through trial and error. Averaging over 100 shares the results
converged nicely to the miner's calculated hash rate for a cross section of algos.

Code:

// Bitcoin formula for converting a share's difficulty to an equivalent
// number of hashes.
//
//   https://en.bitcoin.it/wiki/Difficulty
//
//   H = D * 2**48 / 0xffff
//     = D * 2**32
//
// That formula doesn't seem to be accurate but an adjustment to the
// constant produces correct results.
//
// The formula used is:
//
//   hash = sharediff * 2**48 / 0x3fff
//        = sharediff * 2**30
//        = sharediff * diff2hash

const uint64_t diff2hash = 0x40000000ULL;

Although the numbers work I have no explanation for the discrepency with the documented
formula. I chose to decrease the denominator by a factor of 4 but increasing the numerator
would have the same effect so I don't know which one is "in error".

Is it simply a documentation error or am I missing something?

Gin & veil both claim they use X16RT but they are listed seperately at zergpool.
Suprminer X16RT only works for VEIL.

For GIN the miner hangs after setting stratum difficulty message, waiting for work that never comes.
I've waiting several minutes. I've seen delays of a few seconds on occasion for
some algos/pools but eventually the work arrives. With GIN it never arrives.
It's the same at zergpool and zpool.

Clearly there's a difference if zergpool lists it seperately but what is it and how to
make it work?

There has been some discussion about the effects of auto-exchange multipools and services like
Nicehash on the survival of altcoins. Many believe these services "kill" coins.

From my perspective coins will live or die on their own regardless how how they are mined. Mining only
affects mining.

Why is a coin overmined? Simple, because it's profitable to do so, which is a good indicator of the coin's health.
It means there are buyers. If the buying dries up the price drops and mining becomes no longer profitable.
Trading volume is good even if much of the sell volume is auto-dumping.

The biggest impact of large mining operations is dramatic swings in hash rate as hash moves from one coin/algo
to another. Coins need to be able to adapt to these changes in real time in order to maintain a reasonably constant
supply of new coins. Coins that fail to do this will die.

Auto-exchange pools, Nicehash, large farms, rentals are a real part of mining and coins have to be designed to take
this into account if they want to survive.

Light your flamethrowers...

It's a boring Sunday afternoon so this topic popped into my head. There' been a lot of discussion about
rig building with some nice pictures, very interesting stuff.

But how big is too big? What is the limiting factor? Power limits of household circuits comes to mind
but that can be overcome with commercial power. Hard limits in software? With a well matched CPU and
lots of RAM just how many cards could a single rig support? Most big rigs seem to have 6 cards,
are there any bigger?

Proof of physical work, that is...

http://fitcoin.chaoticmoon.com

If this becomes tradeable on the exchanges it could be very interesting.  Maybe I need to buy a
treadmill and start mining.

Proof of physical work, that is...

http://fitcoin.chaoticmoon.com

If this becomes tradeable on the exchanges it could be very interesting. Will fitness fanatics work
their butts off and sell their coins to lazy gamers? Maybe I need to buy an exercise bike and start
mining. I wonder how much an hour of screen time would be worth.

Greetings

I have recently forked cpuminer and have undertaken a redesign of the mining engine,
better known as miner_thread.

It should be compatible with all miners that use the Pooler/Garzik front end.

Follow progress in the cpuminer-opt thread.

https://bitcointalk.org/index.php?topic=1326803.msg13720909#msg13720909

This redesign may not be very useful to single algo miners, it biggest benefit
is the ability to add new algos quickly and easilly.

Greetings

I have recently forked cpuminer and have undertaken a redesign of the mining engine,
better known as miner_thread.

It should be compatible with all miners that use the Pooler/Garzik front end.

Follow progress in the cpuminer-opt thread.

https://bitcointalk.org/index.php?topic=1326803.msg13720909#msg13720909

[This thread is locked. all discussion of cpuminer-opt should now take placein the new thread started by my alter ego JayDDee.]

This is the home of cpuminer-opt, the optimized CPU miner.

This thread is locked. all discussion of cpuminer-opt should now take place
in the new thread started by my alter ego JayDDee.

https://bitcointalk.org/index.php?topic=5226770.msg53865575#msg53865575

----------------------------------------------------------

Supporting over 90 agorithms with many optimized for CPUs with the latest technologies:

AMD Ryzen: AVX2, SHA
Intel Skylake X: AVX512
Intel Icelake: AVX512, SHA, and VAES  (source code only at this time)

Older CPUs with SSE2 are also supported.

Unique features

Block and share time estimates.

True hashrate reporting with comparison with actual share submission rate.

Download

Source code and Windows binaries can be downloaded from git.

https://github.com/JayDDee/cpuminer-opt/releases

Download only from the official JayDDee github repository. There is malware masquerading
as cpuminer-opt even with fake ANN posts that look just like this one.

New in v3.12.3

Issue #238: Fixed skunk AVX2.

Issue #239: Faster AVX2 & AVX512 for skein +44%, skein2 +30%, plus marginal
increases for skunk, x16r, x16rv2, x16rt, x16rt-veil, x16s, x21s.

Faster anime VAES +57%, AVX512 +21%, AVX2 +3%.

Redesigned code reponsible for issue #236.


New in v3.12.2

Fixed xevan, skein, skein2 AVX2, #238.

Reversed polarity of AVX2 vector bit test utilities, and all users, to be
logically and semantically correct. Follow up to issue #236.

New in v3.12.1

Fixed anime AVX2 low difficulty shares, git issue #236.

Periodic summary now reports lost hash rate due to rejected and stale shares,
displayed only when non-zero.

New in v3.12.0.1

Fixed hodl rejects, git issue #237.

Fixed debug code added in v3.12.0 to work with AVX2 to be enabled only
after low difficulty share have been seen to avoid unnecessarily excessive
log outout.

Added more digits of precision to diff in log output to help diagnose
low difficulty shares.

New in v3.12.0

Faster phi2 AVX2 +62%, AVX512 +150% on Intel CPUs. AMD Ryzen AVX2 is
YMMV due to its inferiour AVX2 implementation.

Fixed Hodl stats, rejects are still an issue since v3.9.5, git issue #237.

API can now be enabled with "-b port" or "--api-bind port".
It will use the default address 127.0.0.1.

Editorial: Short form options should only be used on the command line to save
typing. Configuration files and scripts should always use the long form
"--api-bind addr:port" without relying on any defaults. This is a general
recommendation that applies to all options for any application.

Removed obsolete cryptonight, all variants, and supporting code for more
size reduction and faster compiling.

Tweaked the timing of the CPU temperature and frequency log (Linux only).

Added some debug code to collect more info about low difficulty rejects,
git issue #236.

Requirements:

1. A x86_64 architecture CPU with a minimum of SSE2 support. This includes Intel Core2 and newer and AMD equivalents.
In order to take advantage of AES_NI optimizations a CPU with AES_NI is required. This includes Intel Westmere and newer
and AMD equivalents. Further optimizations are available on some algos for CPUs with AVX and AVX2, Sandybridge and
Haswell respectively.

32 bit CPUs and ARM CPUs are not supported.

2. 64 bit Linux OS. Ubuntu and Fedora based distributions, including Mint and Centos are known to work and have all
dependencies in their repositories. Others may work but may require more effort.

64 bit Windows OS is supported using the pre-compiled binaries package or may be compiled with mingw_w64 and msys.

Apple and Android operating systems are not supported. FreeBSD YMMV.

Older CPUs, other architectures and operating systems may be supported by TPruvot's cpuminer-multi.

Security warning

Miner programs are often flagged as malware by antivirus programs. This is usually a false positive, they are
flagged simply because they are cryptocurrency miners. However, some malware has been spread using the
cover that miners are known to be subject to false positives. Always be on alert. The source code of cpuminer-opt
is open for anyone to inspect. If you don't trust the software don't download it.

Some cryptographic code has been taken from trusted sources but has been modified for speed at the expense of
accepted security practices. This code should not be imported into applications where secure cryptography is
required.

Errata:

Old algorithms that are rarely used anymore will not get the latest optimizations.

Cryptonight and variants are no longer supported.

Neoscrypt crashes on Windows, use legacy version.

Hodl requires a CPU with AES, use legacy version if without.

Benchmark testing does not work on several algos.

Donations

cpuminer-opt has no fees of any kind but donations are accepted.

BTC: 12tdvfF7KmAsihBXQXynT6E6th2c2pByTT