[Oliver] wiped the hard drive from a Macbook Pro using the ‘dd’ command on another machine. This does a great job of getting everything off the drive, but he was still faced with the EFI PIN lock protection when he tried to put it back into the Mac. You used to be able to clear the NVRAM to get around this issue, but that exploit has now been patched. So [Oliver] set out to use a microcontroller to brute-force the EFI PIN.
You can read his back story at the link above. He had the chance to enter a 4-digit pin before the format process. Now that he’s wiped the drive the code is at least 6 characters long, which is a lot more possibilities (at least it’s numeric characters only!). To automate the process he programmed this Teensy board to try every possible combination. It worked great on a text editor but sometimes the characters, or the enter command wouldn’t register. He guesses this was some type of protection against automated attackers. To get around the issue he added different delays between the key presses, and between entering each code. This fixed the issue, as you can see in the clip after the break. Unfortunately after two 48-hour runs that tried every code he still hasn’t gained access!
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[Steve] needed an alternative to the Xserve, since Apple stopped making it. His solution was to stick 160 Mac Minis into a rack. That’s 640 real cores, or 1280 if you count HyperThreading.
First, Steve had to tackle the shelving. Nobody made a 1U shelf to hold four Minis, so [Steve] worked with a vendor to design his own. Once challenge of this was managing the exaust air of each Mini. Plastic inserts were designed to ensure that exaust wasn’t sucked into the intake of an adjancent Mini.
An array of 160 computers is going to throw a lot of heat. To provide sufficient airflow, [Steve] built a custom cooling door out of four car radiators fans, connected to a 40A DC motor controller. This was all integrated into the door of the rack.
Another challenge was getting power to all of the Minis. Since this deisgn was for a data center, the Minis would have to draw power from a Power Distribution Unit (PDU). This would have required a lot of PDUs, and a lot of cables. The solution: a one to four Y cable for the Minis. This allows each shelf of four to plug into a single outlet.
The final result is a professional looking rack that can replace a rack of Xserves, and has capacity to be upgraded in the future.
We’ve tried building our own ARM cross compiler on a Linux box and it’s no picnic. Luckily there is a free cross compiling toolchain available through Mentor Graphics (formerly called Code Sourcery G++). But those looking to develop on a Mac aren’t so lucky. There is help via a script, and [Michael] wrote a guide detailing how to use crosstool-ng to build an ARM toolchain on Mountain Lion.
Crosstool-ng is a script which automates much of what is needed when compiling all the different components. But there is a some groundwork that needs to be in place before you can run it. For instance, some of the tools that ship with OSX aren’t entirely compatible with the GNU tools the script is looking for. One example is ‘grep’. Mountain Lion has the BSD version of grep but it is missing a few of the GNU version’s commands used by crosstool-ng. [Michael] will guide you through this and a handful of other issues until you have a functioning toolchain up and running.
We missed the original announcement, but Apple unveiled more than just the iPad Mini at their last event. They’ve got a new storage system called Fusion Drive which is supposed to combine the access speeds of solid state with the storage density of platter drives. When you look just under the surface what you’re really seeing is a disc drive with grossly enlarged cache in the form of an SSD drive. How about moving from the 64 MB or so of cache seen on many large hard drives today to something like 64GB?
Well you don’t have to wait for Apple to do it. [Patrick Stein] gave it a shot using command line tools to combine an SSD with a physical drive. Sure, it’s not an all-in-one solution, but it is a pretty good proof. The linchpin that will really make it possible is a low-level driver that can handle the caching on the SDD, while ensuring that the data eventually makes it to the platter for long-term storage.
Many have tried to put together an easy package for running software defined radio packages on the Mac. Not many have succeeded the way [Elias]’ port of the gqrx SDR package has. It’s simply the easiest way to get a software defined radio up and running on the mac.
gqrx is a front end for the very popular GNU Radio software defined radio toolkit. Originally designed for the FUNcube SDR dongle, gqrx can also be made to work with one of the many, many USB TV tuners that have come out of China this past year for use as a software radio.
[Elias]’ port of gqrx isn’t the first app to put software defined radio on the Mac, but it certainly is the easiest. Simply by downloading [Elias] disk image, plugging in a TV tuner dongle, and starting the app, I was able to have a software radio receiver on my MacBook Air in less than a minute.
Everything required by GNU Radio and gqrx is already included, making this the easiest way to get SDR on a Mac. Very awesome work from [Elias], and we thank him.
If you’ve got an old mouse sitting around that has that perfect retro look why not start using it again? We’d bet there’s just enough room in there to turn the input device wireless.
The hack does away with everything but the case. The guts from a brand new wireless laser mouse are used as replacements. For the most part this is a simple process of making room for the new board and laying it in place. It involves cutting off a few plastic case nubs, enlarging the hole on the bottom so that the laser has a clear line of sight to the desktop, and hot gluing the thing in place. The button cover had a bit of plastic glued in place so that it lines up correctly with the replacement mouse’s switch.
The only thing that didn’t work out well is the battery situation. The AA cell that the mouse needs was too big for the retrofit so it was swapped with an AAA. These have a lower capacity which means more frequent replacement.
[Paul] spent his summer bringing an iMac G3 into this decade. There’s plenty of room to work with since he removed the CRT which originally occupied most of the computer’s space. The final project is much more powerful and since he preserved most of the metal mounting parts inside it remains quite strong.
He started by swapping flat screen monitors with his Grandma (who incidentally runs Linux… nice!). She had a 15″ model which would fit nicely in the case so he upgraded her to 17″ and took the old one. With bezel removed it fits perfectly where to old tube had been. Next comes the power supply. It’s mounted on the bracket which held the back of the tube, with a bit of metal removed to clear the air intake. To mount the motherboard he fabricated a bracket at one end where the iMac’s stage drops away. In retrospect he wishes he had rotated the board to make the I/O panel more accessible. The hard drive mounts on the original carriage, and he did some creative gluing to make his replacement DVD drive align with the original optical drive opening. The finished product looks great from the front and sides, with the cables running out the back as the only indication that it’s had some major work done on it.