A Macbook Air And A Thunderbolt GPU

July 31, 2013 by Brian Benchoff 73 Comments

When Intel and Apple released Thunderbolt, hallelujahs from the Apple choir were heard. Since very little in any of Apple’s hardware lineup is upgradeable, an external video card is the best of all possible world. Unfortunately, Intel doesn’t seem to be taking kindly to the idea of external GPUs. That hasn’t stopped a few creative people like [Larry Gadea] from figuring it out on their own. Right now he’s running a GTX 570 through the Thunderbolt port of his MacBook Air, and displaying everything on the internal LCD. A dream come true.

[Larry] is doing this with a few fairly specialized bits of hardware. The first is a Thunderbolt to ExpressCard/34 adapter, after that an ExpressCard to PCI-E adapter. Couple that with a power supply, GPU, and a whole lot of software configuration, and [Larry] had a real Thunderbolt GPU on his hands.

There are, of course, a few downsides to running a GPU through a Thunderbolt port. The current Thunderbolt spec is equivalent to a PCI-E 4X slot, a quarter of what is needed to get all the horsepower out of high-end GPUs. That being said, it is an elegant-yet-kludgy way for better graphics performance on the MBA,

Demo video below.

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Mac Malware Uses Right To Left Character Exploit

July 22, 2013 by Mike Szczys 50 Comments

right-to-left-character-malware-attack

Check out this jumbled confirmation window. At first glance the message appears to contain a bunch of gibberish, but it can actually be read if you start at the right side and read each character moving left. The text displays like this because it is prefixed by a special Right-to-Left override Unicode character. The technique is being used in malware to obscure the actual extension of the file being launched. Notice that when written backwards your eye can still pick out the string “pdf” which may be enough to trick the uninitiated into approving the launch of the file.

This confirmation screen is launched when clicking on a piece of malware found in the wild a little over a week ago. If you do choose to run it, a decoy PDF file is opened in order not to arouse suspicion. But at the same time the program — which is signed with an Apple Developer ID — is installing itself in the home directory and making a cron job to launch at each boot. Sneaky!

Apple MagSafe Protocol Hacking

June 7, 2013 by Mike Szczys 4 Comments

[Ken Shirriff] was interested in how the Apple MagSafe works. Specifically he wanted to know what controlled the LED on the connector itself so he tore one open to see what is inside. There’s a chip present and he didn’t waste time figuring out how the MagSafe communication protocol works.

The DS2413 chip he found on the MagSafe’s tiny little PCB has just six pins. Two of these control a pair of LEDs, which give the indicator its color range. Another pin is used for 1-wire communications. When polled the charger will return a 64-bit identification number that includes a variety of information. [Ken] looks into what data is offered from several different models of charger by using the Arduino setup above. But the results are not entirely straight-forward as he discusses in his article. The 1-wire protocol is also used to switch the LEDs. This process is the responsibility of the computer being charged, but [Ken] shows how the colors can be cycled using an Arduino (with a couple of 9-volts as a source instead of a connection to mains).

Apple MagSafe Cord Repair

April 17, 2013 by Mike Szczys 44 Comments

[Tommy Ward] had a big problem with the cord for his laptop power supply. This thing’s not cheap so he figured out a way to fix the frayed cord on his Apple MagSafe. He asserts that the shortened rubber collar on the plug end of the cord is to blame for this type of damage. We think rough use may have something to do with it too, but having had to repair our own feline-damaged power cords we’re not about to start pointing fingers.

To pull off an appropriate fix [Tommy] pries apart the case housing the power converter. This lets him get at the solder connections of the cord. After removing it from the circuit board he clips off the damaged portion of the cable. To reuse the strain relief grommet he drilled out the old portion of wire and insulation, making room for the undamaged cable to pass through, adding a cable tie on the inside to aide in strain relief. The last part of the fix involves gluing everything back together.

If your power supply problems have to do with the computer connector itself there’s a fix for that too.

Hacked Together Mac Isn’t A Hackintosh

April 16, 2013 by Mike Szczys 59 Comments

hacked-together-macintosh

Check out this 20″ iMac. Notice anything peculiar? Look closely at the branding above the Apple logo. The only thing that tips you off that this iMac is a hacked together unit is that Acer logo on the replacement screen.

As we’ve so often been caught doing, [Flippy] was browsing eBay for deals. It’s a dangerous activity because you end up falling into purchases like an Aluminum iMac for $35. That led to the purchase of a very slim LED LCD monitor to use as the display. It fits perfectly behind the iMac’s glass bezel, which has a tiny chip in the upper right corner that doesn’t bother [Flippy]. It’s thin enough that this actually left room for him to add in the guts of a MacBook Pro which he had sitting in his unused parts pile. With all of the main components accounted for the rest is really just logistics like routing all of the cable connectors and adding openings for USB ports. What he ended up with is a high-end computer for a low-end price.

Mac EFI PIN Lock Brute Force Attack (unsuccessful)

February 26, 2013 by Mike Szczys 82 Comments

[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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160 Mac Minis, One Rack

December 9, 2012 by Eric Evenchick 128 Comments

[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.

mac-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.