bfgminer/NEWS

Version 1.6.1 - August 29, 2011

- Copy cgminer path, not cat it.
- Switching between redrawing windows does not fix the crash with old
libncurses, so redraw both windows, but only when the window size hasn't
changed.
- Reinstate minimum 1 extra in queue to make it extremely unlikely to ever have
0 staged work items and any idle time.
- Return -1 if no input is detected from the menu to prevent it being
interpreted as a 0.
- Make pthread, libcurl and libcurses library checks mandatory or fail.
- Add a --disable-opencl configure option to make it possible to override
detection of opencl and build without GPU mining support.
- Confusion over the variable name for number of devices was passing a bogus
value which likely was causing the zero sized binary issue.
- cgminer no longer supports default url user and pass so remove them.
- Don't show value of intensity since it's dynamic by default.
- Add options to explicitly enable CPU mining or disable GPU mining.
- Convert the opt queue into a minimum number of work items to have queued
instead of an extra number to decrease risk of getting idle devices without
increasing risk of higher rejects.
- Statify tv_sort.
- Check for SSE2 before trying to build 32 bit SSE2 assembly version. Prevents
build failure when yasm is installed but -msse2 is not specified.
- Add some defines to configure.ac to enable exporting of values and packaging,
and clean up output.
- Give convenient summary at end of ./configure.
- Display version information and add --version command line option, and make
sure we flush stdout.
- Enable curses after the mining threads are set up so that failure messages
won't be lost in the curses interface.
- Disable curses after inputting a pool if we requested no curses interface.
- Add an option to break out after successfully mining a number of accepted
shares.
- Exit with a failed return code if we did not reach opt_shares.
- The cpu mining work data can get modified before we copy it if we submit it
async, and the sync submission is not truly sync anyway, so just submit it sync.


Version 1.6.0 - August 26, 2011

- Make restarting of GPUs optional for systems that hang on any attempt to
restart them.     Fix DEAD status by comparing it to last live time rather than
last attempted restart time since that happens every minute.
- Move staged threads to hashes so we can sort them by time.
- Create a hash list of all the blocks created and search them to detect when a
new block has definitely appeared, using that information to detect stale work
and discard it.
- Update configure.ac for newer autoconf tools.
- Use the new hashes directly for counts instead of the fragile counters
currently in use.
- Update to latest sse2 code from cpuminer-ng.
- Allow LP to reset block detect and block detect lp flags to know who really
came first.
- Get start times just before mining begins to not have very slow rise in
average.
- Add message about needing one server.
- We can queue all the necessary work without hitting frequent stales now with
the time and string stale protection active all the time.     This prevents a
pool being falsely labelled as not providing work fast enough.
- Include uthash.h in distro.
- Implement SSE2 32 bit assembly algorithm as well.
- Fail gracefully if unable to open the opencl files.
- Make cgminer look in the install directory for the .cl files making make
install work correctly.
- Allow a custom kernel path to be entered on the command line.
- Bump threshhold for lag up to maximum queued but no staged work.
- Remove fragile source patching for bitalign, vectors et. al and simply pass it
with the compiler options.
- Actually check the value returned for the x-roll-ntime extension to make sure
it isn't saying N.
- Prevent segfault on exit for when accessory threads don't exist.
- Disable curl debugging with opt protocol since it spews to stderr.


Version 1.5.8 - August 23, 2011

- Minimise how much more work can be given in cpu mining threads each interval.
- Make the fail-pause progressively longer each time it fails until the network
recovers.
- Only display the lagging message if we've requested the work earlier.
- Clean up the pool switching to not be dependent on whether the work can roll
or not by setting a lagging flag and then the idle flag.
- Only use one thread to determine if a GPU is sick or well, and make sure to
reset the sick restart attempt time.
- The worksize was unintentionally changed back to 4k by mistake, this caused a
slowdown.


Version 1.5.7 - August 22, 2011

- Fix a crash with --algo auto
- Test at appropriate target difficulty now.
- Add per-device statics log output with --per-device-stats
- Fix breakage that occurs when 1 or 4 vectors are chosen on new phatk.
- Make rolltime report debug level only now since we check it every work
item.
- Add the ability to enable/disable per-device stats on the fly and match
logging on/off.
- Explicitly tell the compiler to retain the program to minimise the chance of
the zero sized binary errors.
- Add one more instruction to avoid one branch point in the common path in the
cl return code. Although this adds more ALUs overall and more branch points, the
common path code has the same number of ALUs and one less jmp, jmps being more
expensive.
- Explicitly link in ws2_32 on the windows build and update README file on how
to compile successfully on windows.
- Release cl resources should the gpu mining thread abort.
- Attempt to restart a GPU once every minute while it's sick.
- Don't kill off the reinit thread if it fails to init a GPU but returns safely.
- Only declare a GPU dead if there's been no sign of activity from the reinit
thread for 10 mins.
- Never automatically disable any pools but just specify them as idle if they're
unresponsive at startup.
- Use any longpoll available, and don't disable it if switching to a server that
doesn't have it. This allows you to mine solo, yet use the longpoll from a pool
even if the pool is the backup server.
- Display which longpoll failed and don't free the ram for lp_url since it
belongs to the pool hdr path.
- Make the tcp setsockopts unique to linux in the hope it allows freebsd et. al
to compile.


Version 1.5.6 - August 17, 2011

- New phatk and poclbm kernels. Updated phatk to be in sync with latest 2.2
courtesy of phateus. Custom modified to work best with cgminer.
- Updated output buffer code to use a smaller buffer with the kernels.
- Clean up the longpoll management to ensure the right paths go to the right
pool and display whether we're connected to LP or not in the status line.


Version 1.5.5 - August 16, 2011

- Rework entirely the GPU restart code. Strike a balance between code that
re-initialises the GPU entirely so that soft hangs in the code are properly
managed, but if a GPU is completely hung, the thread restart code fails
gracefully, so that it does not take out any other code or devices. This will
allow cgminer to keep restarting GPUs that can be restarted, but continue
mining even if one or more GPUs hangs which would normally require a reboot.
- Add --submit-stale option which submits all shares, regardless of whether they
would normally be considered stale.
- Keep options in alphabetical order.
- Probe for slightly longer for when network conditions are lagging.
- Only display the CPU algo when we're CPU mining.
- As we have keepalives now, blaming network flakiness on timeouts appears to
have been wrong.     Set a timeout for longpoll to 1 hour, and most other
network connectivity to 1 minute.
- Simplify output code and remove HW errors from CPU stats.
- Simplify code and tidy output.
- Only show cpu algo in summary if cpu mining.
- Log summary at the end as per any other output.
- Flush output.
- Add a linux-usb-cgminer guide courtesy of Kano.


Version 1.5.4 - August 14, 2011

- Add new option: --monitor <cmd> Option lets user specify a command <cmd> that
will get forked by cgminer on startup. cgminer's stderr output subsequently gets
piped directly to this command.
- Allocate work from one function to be able to initialise variables added
later.
- Add missing fflush(stdout) for --ndevs and conclusion summary.
- Preinitialise the devices only once on startup.
- Move the non cl_ variables into the cgpu info struct to allow creating a new
cl state on reinit, preserving known GPU variables.
- Create a new context from scratch in initCQ in case something was corrupted to
maximise our chance of succesfully creating a new worker thread. Hopefully this
makes thread restart on GPU failure more reliable, without hanging everything
in the case of a completely wedged GPU.
- Display last initialised time in gpu management info, to know if a GPU has
been re-initialised.
- When pinging a sick cpu, flush finish and then ping it in a separate thread in
the hope it recovers without needing a restart, but without blocking code
elsewhere.
- Only consider a pool lagging if we actually need the work and we have none
staged despite queue requests stacking up. This decreases significantly the
amount of work that leaks to the backup pools.
- The can_roll function fails inappropriately in stale_work.
- Only put the message that a pool is down if not pinging it every minute. This
prevents cgminer from saying pool down at 1 minute intervals unless in debug
mode.
- Free all work in one place allowing us to perform actions on it in the future.
- Remove the extra shift in the output code which was of dubious benefit. In
fact in cgminer's implementation, removing this caused a miniscule speedup.
- Test each work item to see if it can be rolled instead of per-pool and roll
whenever possible, adhering to the 60 second timeout. This makes the period
after a longpoll have smaller dips in throughput, as well as requiring less
getworks overall thus increasing efficiency.
- Stick to rolling only work from the current pool unless we're in load balance
mode or lagging to avoid aggressive rolling imitating load balancing.
- If a work item has had any mining done on it, don't consider it discarded
work.


Version 1.5.3 - July 30, 2011

- Significant work went into attempting to make the thread restart code robust
to identify sick threads, tag them SICK after 1 minute, then DEAD after 5
minutes of inactivity and try to restart them. Instead of re-initialising the
GPU completely, only a new cl context is created to avoid hanging the rest of
the GPUs should the dead GPU be hung irrevocably.
- Use correct application name in syslog.
- Get rid of extra line feeds.
- Use pkg-config to check for libcurl version
- Implement per-thread getwork count with proper accounting to not over-account
queued items when local work replaces it.
- Create a command queue from the program created from source which allows us
to flush the command queue in the hope it will not generate a zero sized binary
any more.
- Be more willing to get work from the backup pools if the work is simply being
queued faster than it is being retrieved.


Version 1.5.2 - July 28, 2011

- Restarting a hung GPU can hang the rest of the GPUs so just declare it dead
and provide the information in the status.
- The work length in the miner thread gets smaller but doesn't get bigger if
it's under 1 second.     This could end up leading to CPU under-utilisation and
lower and lower hash rates.     Fix it by increasing work length if it drops
under 1 second.
- Make the "quiet" mode still update the status and display errors, and add a
new --real-quiet option which disables all output and can be set once while
running.
- Update utility and efficiency figures when displaying them.
- Some Intel HD graphics support the opencl commands but return errors since
they don't support opencl. Don't fail with them, just provide a warning and
disable GPU mining.
- Add http:// if it's not explicitly set for URL entries.
- Log to the output file at any time with warnings and errors, instead of just
when verbose mode is on.
- Display the correct current hash as per blockexplorer, truncated to 16
characters, with just the time.


Version 1.5.1 - July 27, 2011

- Two redraws in a row cause a crash in old libncurses so just do one redraw
using the main window.
- Don't adjust hash_div only up for GPUs. Disable hash_div adjustment for GPUs.
- Only free the thread structures if the thread still exists.
- Update both windows separately, but not at the same time to prevent the double
refresh crash that old libncurses has.     Do the window resize check only when
about to redraw the log window to minimise ncurses cpu usage.
- Abstract out the decay time function and use it to make hash_div a rolling
average so it doesn't change too abruptly and divide work in chunks large enough
to guarantee they won't overlap.
- Sanity check to prove locking.
- Don't take more than one lock at a time.
- Make threads report out when they're queueing a request and report if they've
failed.
- Make cpu mining work submission asynchronous as well.
- Properly detect stale work based on time from staging and discard instead of
handing on, but be more lax about how long work can be divided for up to the
scantime.
- Do away with queueing work separately at the start and let each thread grab
its own work as soon as it's ready.
- Don't put an extra work item in the queue as each new device thread will do so
itself.
- Make sure to decrease queued count if we discard the work.
- Attribute split work as local work generation.
- If work has been cloned it is already at the head of the list and when being
reinserted into the queue it should be placed back at the head of the list.
- Dividing work is like the work is never removed at all so treat it as such.
However the queued bool needs to be reset to ensure we *can* request more work
even if we didn't initially.
- Make the display options clearer.
- Add debugging output to tq_push calls.
- Add debugging output to all tq_pop calls.


Version 1.5.0 - July 26, 2011

- Increase efficiency of slow mining threads such as CPU miners dramatically. Do
this by detecting which threads cannot complete searching a work item within the
scantime and then divide up a work item into multiple smaller work items.
Detect the age of the work items and if they've been cloned before to prevent
doing the same work over. If the work is too old to be divided, then see if it
can be time rolled and do that to generate work. This dramatically decreases the
number of queued work items from a pool leading to higher overall efficiency
(but the same hashrate and share submission rate).
- Don't request work too early for CPUs as CPUs will scan for the full
opt_scantime anyway.
- Simplify gpu management enable/disable/restart code.
- Implement much more accurate rolling statistics per thread and per gpu and
improve accuracy of rolling displayed values.
- Make the rolling log-second average more accurate.
- Add a menu to manage GPUs on the fly allowing you to enable/disable GPUs or
try restarting them.
- Keep track of which GPUs are alive versus enabled.
- Start threads for devices that are even disabled, but don't allow them to
start working.
- The last pool is when we are low in total_pools, not active_pools.
- Make the thread restart do a pthread_join after disabling the device, only
re-enabling it if we succeed in restarting the thread. Do this from a separate
thread so as to not block any other code.This will allow cgminer to continue
even if one GPU hangs.
- Try to do every curses manipulation under the curses lock.
- Only use the sockoptfunction if the version of curl is recent enough.


Version 1.4.1 - July 24, 2011

- Do away with GET for dealing with longpoll forever. POST is the one that works
everywhere, not the other way around.
- Detect when the primary pool is lagging and start queueing requests on backup
pools if possible before needing to roll work.
- Load balancing puts more into the current pool if there are disabled pools.
Fix.
- Disable a GPU device should the thread fail to init.
- Out of order command queue may fail on osx. Try without if it fails.
- Fix possible dereference on blank inputs during input_pool.
- Defines missing would segfault on --help when no sse mining is built in.
- Revert "Free up resources/stale compilers." - didn't help.
- Only try to print the status of active devices or it would crash.
- Some hardware might benefit from the less OPS so there's no harm in leaving
kernel changes that do that apart from readability of the code.

Version 1.4.0 - July 23, 2011

- Feature upgrade: Add keyboard input during runtime to allow modification of
and viewing of numerous settings such as adding/removing pools, changing
multipool management strategy, switching pools, changing intensiy, verbosity,
etc. with a simple keypress menu system.
- Free up resources/stale compilers.
- Kernels are safely flushed in a way that allows out of order execution to
work.
- Sometimes the cl compiler generates zero sized binaries and only a reboot
seems to fix it.
- Don't try to stop/cancel threads that don't exist.
- Only set option to show devices and exit if built with opencl support.
- Enable curses earlier and exit with message in main for messages to not be
lost in curses windows.
- Make it possible to enter server credentials with curses input if none are
specified on the command line.
- Abstract out a curses input function and separate input pool function to allow
for live adding of pools later.
- Remove the nil arguments check to allow starting without parameters.
- Disable/enable echo & cbreak modes.
- Add a thread that takes keyboard input and allow for quit, silent, debug,
verbose, normal, rpc protocol debugging and clear screen options.
- Add pool option to input and display current pool status, pending code to
allow live changes.
- Add a bool for explicit enabling/disabling of pools.
- Make input pool capable of bringing up pools while running.
- Do one last check of the work before submitting it.
- Implement the ability to live add, enable, disable, and switch to pools.
- Only internally test for block changes when the work matches the current pool
to prevent interleaved block change timing on multipools.
- Display current pool management strategy to enable changing it on the fly.
- The longpoll blanking of the current_block data may not be happening before
the work is converted and appears to be a detected block change.     Blank the
current block be
- Make --no-longpoll work again.
- Abstract out active pools count.
- Allow the pool strategy to be modified on the fly.
- Display pool information on the fly as well.
- Add a menu and separate out display options.
- Clean up the messy way the staging thread communicates with the longpoll
thread to determine who found the block first.
- Make the input windows update immediately instead of needing a refresh.
- Allow log interval to be set in the menu.
- Allow scan settings to be modified at runtime.
- Abstract out the longpoll start and explicitly restart it on pool change.
- Make it possible to enable/disable longpoll.
- Set priority correctly on multipools.     Display priority and alive/dead
information in display_pools.
- Implement pool removal.
- Limit rolltime work generation to 10 iterations only.
- Decrease testing log to info level.
- Extra refresh not required.
- With huge variation in GPU performance, allow intensity to go from -10 to +10.
- Tell getwork how much of a work item we're likely to complete for future
splitting up of work.
- Remove the mandatory work requirement at startup by testing for invalid work
being passed which allows for work to be queued immediately.     This also
removes the requirem
- Make sure intensity is carried over to thread count and is at least the
minimum necessary to work.
- Unlocking error on retry. Locking unnecessary anyway so remove it.
- Clear log window from consistent place. No need for locking since logging is
disabled during input.
- Cannot print the status of threads that don't exist so just queue enough work
for the number of mining threads to prevent crash with -Q N.
- Update phatk kernel to one with new parameters for slightly less overhead
again.     Make the queue kernel parameters call a function pointer to select
phatk or poclbm.
- Make it possible to select the choice of kernel on the command line.
- Simplify the output part of the kernel. There's no demonstrable advantage from
more complexity.
- Merge pull request #18 from ycros/cgminer
- No need to make leaveok changes win32 only.
- Build support in for all SSE if possible and only set the default according to
machine capabilities.
- Win32 threading and longpoll keepalive fixes.
- Win32: Fix for mangled output on the terminal on exit.


Version 1.3.1 - July 20, 2011

- Feature upgrade; Multiple strategies for failover. Choose from default which
now falls back to a priority order from 1st to last, round robin which only
changes pools when one is idle, rotate which changes pools at user-defined
intervals, and load-balance which spreads the work evenly amongst all pools.
- Implement pool rotation strategy.
- Implement load balancing algorithm by rotating requests to each pool.
- Timeout on failed discarding of staged requests.
- Implement proper flagging of idle pools, test them with the watchdog thread,
and failover correctly.
- Move pool active test to own function.
- Allow multiple strategies to be set for multipool management.
- Track pool number.
- Don't waste the work items queued on testing the pools at startup.
- Reinstate the mining thread watchdog restart.
- Add a getpoll bool into the thread information and don't restart threads stuck
waiting on work.
- Rename the idlenet bool for the pool for later use.
- Allow the user/pass userpass urls to be input in any order.
- When json rpc errors occur they occur in spits and starts, so trying to limit
them with the comms error bool doesn't stop a flood of them appearing.
- Reset the queued count to allow more work to be queued for the new pool on
pool switch.

Version 1.3.0 - July 19, 2011

- Massive infrastructure update to support pool failover.
- Accept multiple parameters for url, user and pass and set up structures of
pool data accordingly.
- Probe each pool for what it supports.
- Implement per pool feature support according to rolltime support as
advertised by server.
- Do switching automatically based on a 300 second timeout of locally generated
work or 60 seconds of no response from a server that doesn't support rolltime.
- Implement longpoll server switching.
- Keep per-pool data and display accordingly.
- Make sure cgminer knows how long the pool has actually been out for before
deeming it a prolonged outage.
- Fix bug with ever increasing staged work in 1.2.8 that eventually caused
infinite rejects.
- Make warning about empty http requests not show by default since many
servers do this regularly.


Version 1.2.8 - July 18, 2011

- More OSX build fixes.
- Add an sse4 algorithm to CPU mining.
- Fix CPU mining with other algorithms not working.
- Rename the poclbm file to ensure a new binary is built since.
- We now are guaranteed to have one fresh work item after a block change and we
should only discard staged requests.
- Don't waste the work we retrieve from a longpoll.
- Provide a control lock around global bools to avoid racing on them.
- Iterating over 1026 nonces when confirming data from the GPU is old code
and unnecessary and can lead to repeats/stales.
- The poclbm kernel needs to be updated to work with the change to 4k sized
output buffers.
- longpoll seems to work either way with post or get but some servers prefer
get so change to httpget.


Version 1.2.7 - July 16, 2011

- Show last 8 characters of share submitted in log.
- Display URL connected to and user logged in as in status.
- Display current block and when it was started in the status line.
- Only pthread_join the mining threads if they exist as determined by
pthread_cancel and don't fail on pthread_cancel.
- Create a unique work queue for all getworks instead of binding it to thread 0
to avoid any conflict over thread 0's queue.
- Clean up the code to make it clear it's watchdog thread being messaged to
restart the threads.
- Check the current block description hasn't been blanked pending the real
new current block data.
- Re-enable signal handlers once the signal has been received to make it
possible to kill cgminer if it fails to shut down.
- Disable restarting of CPU mining threads pending further investigation.
- Update longpoll messages.
- Add new block data to status line.
- Fix opencl tests for osx.
- Only do local generation of work if the work item is not stale itself.
- Check for stale work within the mining threads and grab new work if
positive.
- Test for idle network conditions and prevent threads from being restarted
by the watchdog thread under those circumstances.
- Make sure that local work generation does not continue indefinitely by
stopping it after 10 minutes.
- Tweak the kernel to have a shorter path using a 4k buffer and a mask on the
nonce value instead of a compare and loop for a shorter code path.
- Allow queue of zero and make that default again now that we can track how
work is being queued versus staged. This can decrease reject rates.
- Queue precisely the number of mining threads as longpoll_staged after a
new block to not generate local work.


Version 1.2.6 - July 15, 2011

- Put a current system status line beneath the total work status line
- Fix a counting error that would prevent cgminer from correctly detecting
situations where getwork was failing - this would cause stalls sometimes
unrecoverably.
- Limit the maximum number of requests that can be put into the queue which
otherwise could get arbitrarily long during a network outage.
- Only count getworks that are real queue requests.


Version 1.2.5 - July 15, 2011

- Conflicting -n options corrected
- Setting an intensity with -I disables dynamic intensity setting
- Removed option to manually disable dynamic intensity
- Improve display output
- Implement signal handler and attempt to clean up properly on exit
- Only restart threads that are not stuck waiting on mandatory getworks
- Compatibility changes courtesy of Ycros to build on mingw32 and osx
- Explicitly grab first work item to prevent false positive hardware errors
due to working on uninitialised work structs
- Add option for non curses --text-only output
- Ensure we connect at least once successfully before continuing to retry to
connect in case url/login parameters were wrong
- Print an executive summary when cgminer is terminated
- Make sure to refresh the status window

Versions -> 1.2.4

- Con Kolivas - July 2011. New maintainership of code under cgminer name.
- Massive rewrite to incorporate GPU mining.
- Incorporate original oclminer c code.
- Rewrite gpu mining code to efficient work loops.
- Implement per-card detection and settings.
- Implement vector code.
- Implement bfi int patching.
- Import poclbm and phatk ocl kernels and use according to hardware type.
- Implement customised optimised versions of opencl kernels.
- Implement binary kernel generation and loading.
- Implement preemptive asynchronous threaded work gathering and pushing.
- Implement variable length extra work queues.
- Optimise workloads to be efficient miners instead of getting lots of extra
  work.
- Implement total hash throughput counters, per-card accepted, rejected and
  hw error count.
- Staging and watchdog threads to prevent fallover.
- Stale and reject share guarding.
- Autodetection of new blocks without longpoll.
- Dynamic setting of intensity to maintain desktop interactivity.
- Curses interface with generous statistics and information.
- Local generation of work (xroll ntime) when detecting poor network
connectivity.

Version 1.0.2

- Linux x86_64 optimisations - Con Kolivas
- Optimise for x86_64 by default by using sse2_64 algo
- Detects CPUs and sets number of threads accordingly
- Uses CPU affinity for each thread where appropriate
- Sets scheduling policy to lowest possible
- Minor performance tweaks

Version 1.0.1 - May 14, 2011

- OSX support

Version 1.0 - May 9, 2011

- jansson 2.0 compatibility
- correct off-by-one in date (month) display output
- fix platform detection
- improve yasm configure bits
- support full URL, in X-Long-Polling header

Version 0.8.1 - March 22, 2011

- Make --user, --pass actually work

- Add User-Agent HTTP header to requests, so that server operators may
  more easily identify the miner client.

- Fix minor bug in example JSON config file

Version 0.8 - March 21, 2011

- Support long polling: http://deepbit.net/longpolling.php

- Adjust max workload based on scantime (default 5 seconds,
  or 60 seconds for longpoll)

- Standardize program output, and support syslog on Unix platforms

- Suport --user/--pass options (and "user" and "pass" in config file),
  as an alternative to the current --userpass

Version 0.7.2 - March 14, 2011

- Add port of ufasoft's sse2 assembly implementation (Linux only)
  This is a substantial speed improvement on Intel CPUs.

- Move all JSON-RPC I/O to separate thread.  This reduces the
  number of HTTP connections from one-per-thread to one, reducing resource
  usage on upstream bitcoind / pool server.

Version 0.7.1 - March 2, 2011

- Add support for JSON-format configuration file.  See example
  file example-cfg.json.  Any long argument on the command line
  may be stored in the config file.
- Timestamp each solution found
- Improve sha256_4way performance.  NOTE: This optimization makes
  the 'hash' debug-print output for sha256_way incorrect.
- Use __builtin_expect() intrinsic as compiler micro-optimization
- Build on Intel compiler
- HTTP library now follows HTTP redirects

Version 0.7 - February 12, 2011

- Re-use CURL object, thereby reuseing DNS cache and HTTP connections
- Use bswap_32, if compiler intrinsic is not available
- Disable full target validation (as opposed to simply H==0) for now

Version 0.6.1 - February 4, 2011

- Fully validate "hash < target", rather than simply stopping our scan
  if the high 32 bits are 00000000.
- Add --retry-pause, to set length of pause time between failure retries
- Display proof-of-work hash and target, if -D (debug mode) enabled
- Fix max-nonce auto-adjustment to actually work.  This means if your
  scan takes longer than 5 seconds (--scantime), the miner will slowly
  reduce the number of hashes you work on, before fetching a new work unit.

Version 0.6 - January 29, 2011

- Fetch new work unit, if scanhash takes longer than 5 seconds (--scantime)
- BeeCee1's sha256 4way optimizations
- lfm's byte swap optimization (improves via, cryptopp)
- Fix non-working short options -q, -r

Version 0.5 - December 28, 2010

- Exit program, when all threads have exited
- Improve JSON-RPC failure diagnostics and resilience
- Add --quiet option, to disable hashmeter output.

Version 0.3.3 - December 27, 2010

- Critical fix for sha256_cryptopp 'cryptopp_asm' algo

Version 0.3.2 - December 23, 2010

- Critical fix for sha256_via

Version 0.3.1 - December 19, 2010

- Critical fix for sha256_via
- Retry JSON-RPC failures (see --retry, under "minerd --help" output)

Version 0.3 - December 18, 2010

- Add crypto++ 32bit assembly implementation
- show version upon 'minerd --help'
- work around gcc 4.5.x bug that killed 4way performance

Version 0.2.2 - December 6, 2010

- VIA padlock implementation works now
- Minor build and runtime fixes

Version 0.2.1 - November 29, 2010

- avoid buffer overflow when submitting solutions
- add Crypto++ sha256 implementation (C only, ASM elided for now)
- minor internal optimizations and cleanups

Version 0.2 - November 27, 2010

- Add script for building a Windows installer
- improve hash performance (hashmeter) statistics
- add tcatm 4way sha256 implementation
- Add experimental VIA Padlock sha256 implementation

Version 0.1.2 - November 26, 2010

- many small cleanups and micro-optimizations
- build win32 exe using mingw
- RPC URL, username/password become command line arguments
- remove unused OpenSSL dependency

Version 0.1.1 - November 24, 2010

- Do not build sha256_generic module separately from cpuminer.

Version 0.1 - November 24, 2010

- Initial release.