Speaking of inspecting source, I inspected yours and am still waiting for you to use a safer password hashing function :-)

(For those not in the know: davout's Bitcoin Central platform hashes passwords with SHA256($pass.$salt). Although safer than the way most people hash passwords, this method is not safe enough because it does not implement iterated hashing to slow down bruteforce attacks. In a scenario where an attacker gains access to BC's hashes via SQL injection for example, the attacker would be able to bruteforce passwords at a rate of 1+ billion per second with one HD 5970. Iterated hashing like Linux's standard MD5-crypt slows this attack by multiple orders of magnitude.)

The level of creativity unlocked by Bitcoin's zero-cost irreversible money transfers is just unthinkable.

What you guys are seeing here is just the beginning :-)

Ugh. I wasn't expecting that much Windows demand.
Oh well I guess I'll have to set up that Windows dev environment which I am not looking forward to

If more than 1 user is interested in Windows, I might consider compiling for Windows.

Actually davout's idea would work: a bounty of about 2500 BTC for me to open source hdminer would be high enough that I could refund most of the money to the buyers who already paid 400 BTC.

I changed my mind.
I am now selling the source code of hdminer as well.
Price remains the same: 400 BTC.

(However it does not mean it is open source. Again people have paid money for it, I don't think they would appreciate it to suddenly become open source.)

.

ribuck makes a valid point why double-precision floating point does not work. To make my own example, if the exact value 3000000.00000001 (about 3M) is stored in a double-precision floating point number, it will be stored as approximately as 3000000.0000000098. Therefore doing any math on this number risks amplifying the rounding error (eg. calculating compounded interest, etc).

To quote an adage from the embedded development world: "if you are using floating point, you probably have not yet understood the problem you are trying to solve".

Do not use floating point to ever store BTC quantities. Use a single 64-bit integer. Or two 32-bit integers to represent the decimal and fractional parts.

Don't store non-fractional values in floating point either. It's not even more developer-friendly than using integers. And it is a dangerous way to either accidentally forget to use double-precision everywhere, or to entice developers receiving such a value from an API to divide by 100000000 to get the decimal point in the right place, leading to inaccurate results.

gavinandresen: Murphy's Law states that some JSON libs are broken. Use integers, don't use floating point.

I do feel that selling proprietary software (the first time for me) is somewhat contrary to my own values as everything else I write and use is open source :-)

hdminer is written in CAL IL (Compute Abstract Layer - Intermediary Language), a pseudo assembly language.

The PS3 is not good for mining. 7 usable cores (6 SPU + 1 PPU) with 128-bit registers at 3.2GHz makes it only about as fast as a cheap 6-core AMD Phenom. Both are handily beaten by low-end GPUs.

Well, out of respect for previous buyers who spent their hard-earned BTC on it, no, I should not...

Faster than Phoenix 1.3 by 6.3%[1] on HD 69xx.
Faster than ArtForz's private calminer on HD 69xx.
hdminer is a miner I developed for AMD Radeon cards using the low-level CAL interface (as opposed to OpenCL). Its target market is cluster owners who operate 20+ GPUs and are power or cooling constrained, yet need that +6.3% perf improvement without increasing power consumption or cooling needs.

• 840 Mhash/sec on a Radeon HD 6990 (BIOS switch at "overclocked" position 1; with "aticonfig --odsc=960,1260" to further overclock the GPU to 960 MHz and mem to 1260 MHz)
• 802 Mhash/sec on a Radeon HD 6990 (BIOS switch at "overclocked" position 1; with "aticonfig --odsc=915,1260" to further overclock the GPU to 915 MHz and mem to 1260 MHz)
• 746 Mhash/sec on a Radeon HD 6990 (BIOS switch at "overclocked" position 1) -- this is higher than the theoretical 723 Mhash/s I would expect for this clock because hdminer leaves some TDP headroom which allows AMD PowerTune to dynamically adjust the clock to a value averaging more than 880MHz
• 708 Mhash/sec on a Radeon HD 6990 (BIOS switch at "default" position 2) -- this speed has been measured with Catalyst 11.1. Catalyst 11.2 through 11.4 contain a performance regression affecting my compute shader that downgrades the speed to 683 Mhash/s. However because aticonfig in Catalyst 11.1 does not support the HD 6990, I advise users to initially install Catalyst 11.4 or later, run aticonfig to generate xorg.conf, then downgrade to 11.1 for operating hdminer on a day-to-day basis.
• 569 Mhash/sec on a Radeon HD 5970 (stock clock 725MHz)

On the HD 69xx series this is about 6.3%[1] faster than the fastest publicly available miner (Phoenix). (On the 5xxx series, hdminer is less optimized and appears to be currently 5% slower than Phoenix.) I am selling it for 250 BTC. Email me m.bevand@gmail.com. Check my user rating on irc/freenode: my nick is "mrb_". What you get:

- Source code (compiles for Linux)
- Supports AMD Radeon HD 5000/6000 series only (HD 4000 and earlier not supported)
- No 100% CPU busy loop! Most combinations of OpenCL miners/Catalyst drivers/SDK versions suffer from a "busy event loop" bug, but not hdminer because it is written in CAL, so does not use OpenCL. A pinky single-core AMD Sempron 140 2.7GHz is amply sufficient to handle the speed of 3 x HD 6990 for example.
- Internal SHA-256 implementation uses BIT_ALIGN and BFI_INT instructions (the first miner ever to do so; read about what is and how I added BFI_INT support to another GPGPU app I wrote: http://blog.zorinaq.com/?e=43)
- Supports as many GPUs as the Catalyst driver can support (currently AMD supports 8 GPUs on Linux, such as 4 x HD6990, or 4 x HD5970)
- Simple command line interface (see screenshot below)
- Connects to bitcoin via the standard RPC 'getwork' interface (compatible with bitcoin version 0.3.19 and up)
- Compatible with mining pools

[1] HD 6990 stock GPU 830MHz clock, stock memory clock, stock GPU VDDC, stock memory voltage: hdminer 708 Mhash/s vs. Phoenix 666 Mhash/s source: http://bitcointalk.org/index.php?topic=2949.msg106238#msg106238

Screenshot of it running on a 4 x dual-GPU HD 5970 computer (8 GPUs total):


Dead easy guide to set it up from scratch from a fresh Ubuntu 10.04 install:

Hi Bitcoin community, this is my first post on the forums.

I upgraded my mining cluster and am selling three Sapphire ATI Radeon HD 4850 X2 graphics cards. Two models available:
a. Sapphire ATI Radeon HD 4850 X2 2GB (100270SR), 2 available, $150 each or 370 BTC
b. Sapphire ATI Radeon HD 4850 X2 1GB (100260SR), 1 available, $130 each or 320 BTC

- If you pay in BTC, at the current difficulty of 18437, these cards will pay themselves back in ~40 days when mining
- If you pay in USD, this is a good deal for a gaming card as a 4850 X2 is as fast as a 5850 ($200+ new)
- They are also great for multiple monitors: 4 HDMI outputs each

Included:
- CrossFire bridge
- Composite and SVGA output adapters
- Original box/packaging
If you ask I will give you these too (ideally I would like to keep them):
- DVI/VGA and DVI/HDMI output adapters
Missing accessories:
- 6-pin/8-pin PCI Express power cable adapters (I absolutely need to keep mine)

I am only looking for local buyers in the Los Angeles area (Redondo Beach).
I will gladly demo the cards to you in a computer.

Email me: m.bevand@gmail.com
Check my user rating on irc/freenode: my nick is "mrb_".