[Hamster] wanted to take a look at division operations when the chip you’re using doesn’t have a divide instruction. He makes the point that the divide instruction takes a lot of space on the die, and that’s why it’s sometimes excluded from a chip’s instruction set. For instance, he tells us the ARM processor used on the Raspberry Pi doesn’t have a divide instruction.
Without hardware division you’re left to implement a binary division algorithm. Eventually [Hamster] plans to do this in an FPGA, but started researching the project by comparing division algorithms in C on an AMD processor.
His test uses all 16-bit possibilities for dividend and divisor. He was shocked to find that binary division doesn’t take much longer than using the hardware instruction for the same tests. A bit of poking around in his code and he manages to beat the AMD hardware divide instruciton by 175%. When testing with an Intel chip the hardware beats his code by about 62%.
He’s got some theories on why he’s seeing these performance differences which we’ll let you check out on your own.
Looks like some hardware enthusiasts have worked out a method to enable debug mode within AMD processors. The original site isn’t loading for us, but the text has been mirrored in this comment. Getting the chip into debug mode requires access passwords on four control registers. We’ve read through the writeup and it means very little to us but we didn’t pull out a datasheet to help make sense of the registers being manipulated. It shouldn’t be hard to find an old AMD system to try this out on. We’d love to hear about anything you do with this debug system.
Recently, research students at Georgia Tech released a report outlining the dangers that GPUs pose to the current state of password security. There are a number of ways to crack a password, all with their different pros and cons, but when it comes down to it, the limiting factor in all of these methods is processing complexity. The more operations that need to be run, the longer it takes, and the less useful each tool is for cracking passwords. In the past, most recommendations for password security revolved around making sure your password wasn’t something predictable, such as “password” or your birthday. With today’s (and tomorrows) GPUs, this may no longer be enough.
Continue reading “GPU Processing and Password Cracking”
With most of us utilizing at least two monitors these days in our day to day operations, six monitors, while an awesome thought, might seem a little too excessive. After all, do we really have space for multiple video cards?
AMD has a new setup in their testing lab that is running six Dell 30inch displays at 7680×3200 through a video card holding six DisplayPort connectors.
Maximum PC has the scoop on the setup, and they say that this single GPU will be coming out on AMD’s DirectX 11 capable chips. Details are slim with the amount of video RAM, speeds and cost not known at present.
Think of the possibilities! Trade shows are one thing, but how about a video wall at home for gaming and movies? How would you use the six monitors shown above? Be sure to leave your ideas in the comments.
[Extra Ketchup] has a couple Neoware thin clients and thought they would make a good robotics platform. It’s a Geode based board that came with Windows CE. He built a small Gentoo system to fit on the 130MB solid state drive. He likes the idea of using it as a platform because the board has serial, parallel, and USB support. The best part is shown above; it can run off of just 4 AA’s.
Frustrated by the constant din of his Xbox 360, [Janne Ström] took action. The original case wouldn’t have near enough room for the additional cooling that needed to be installed, so he picked up Lian Li’s XB01 case replacement. He followed the illustrated disassembly guide to get the Xbox stripped down to just its motherboard. He then began fitting his coolers of choice: two massive Noctua NH-U9D0 units originally intended for AMD Opterons. The asymmetric heat sinks are intended for applications like this where dual sockets could make other devices difficult to place. Clearly the hardest part of the installation was applying an appropriate amount of thermal compound and then slowly tightening the hold down screws to guarantee even pressure. The resultant system ended up being quieter than the first camera he attempted to record it with and the attached power supply. You can see a video of it below.
Continue reading “Finally, a quiet Xbox 360”