By Maddie Stone
Mars may be a frigid, dusty wasteland today, but evidence is mounting that the Red Planet was warm and wet long ago. Future missions to Mars will seek out signs of life
from that livelier era—and a recent geologic analysis has revealed where we should begin our search.
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By Risto Avila
It is now time for the third part of the fast-boot blog post series. In the first post we showed a cluster demo booting in 1.56 seconds, in the second post we opened up how the Qt application was optimized. Here, we will concentrate on the optimization of boot loader and kernel for NXP i.MX6 SABRE development board which was used in the demo.
Before even starting the boot time optimization I measured the unoptimized boot time which was a whopping 22.8 seconds. After measuring we set our goal to get boot time under 2 seconds. Now that the goal was set. I started the optimization from the most obvious place: root-fs. Our existing root-fs contained a lot of stuff that was not required for the startup demo. I stripped down the whole root-fs from 500 MB to 24 MB. I used buildroot to create a bare minimal root-fs for our device and a cross-compile tool chain.
After switching to the smaller root-fs, I did a new measurement of the startup time which was now 15.6 seconds. From this 15.6 seconds kernel, startup took around 6 seconds, the U-Boot bootloader and the unmodified application the rest. Next, I concentrated to the kernel. As I already knew the functionality required by the application, I could easily strip down the kernel from 5.5 MB to 1.6 MB by removing nearly everything that was not required. This got the boot time to 9.26 seconds out of which the kernel startup was taking 1.9 seconds.
At this point we still had not touched the u-boot at all, meaning it had the default 1 second wait time and integrity check of the kernel in place. So U-Boot was next obvious target. Inside U-Boot there is special framework called secondary program loader which is capable of booting another U-Boot or specially configured kernel. I enabled the SPL mode and modified my kernel to include command line arguments and appended my device tree to the kernel. I also stripped down the device tree from 47 KB to 14 KB and disabled console. Boot time was dropped to 3.42 seconds where kernel was taking 0.61 seconds and U-Boot + application rest.
Now that the basic system (u-boot and kernel) was booting already in a decent time, I optimized our cluster application. Start up of the application was changed to load the cluster frame …read more
Source:: http://blog.qt.io/blog/2016/05/25/fast-booting-qt-devices-part-3-optimizing-system-image/
Now you see it, now you don’t. Street artist JR’s latest work has seen him shroud the large pyramid outside the Louvre in Paris with material that, at a glance, makes it look like the structure has disappeared altogether.
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Garden gnomes were never exactly a trendy addition to any home, but if you must fill your garden with tiny ceramic characters, at least go with this …
By Amanda Kooser Fish might not have the most discerning palates, but will they bite for a not-so-delicious-looking broken iPhone? …read more
Source:: http://www.cnet.com/news/can-you-use-an-iphone-as-a-fishing-lure/#ftag=CAD590a51e
Google’s offices in Paris have been raided by the police this morning over investigations about tax fraud.
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Like the idea downloading the contents of a DVD in less then 10 seconds without a cable in sight? That’s exactly what a team of German engineers can do, having broken the record for wireless data transmission using terrestrial radio signals.
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By James Whitbrook on io9, shared by Adam Clark Estes to Gizmodo
Sure, it’s Monday, and Mondays suck. But I think we can all celebrate being near the end of the worst day of the week with a little slice of complete insanity, can’t we?
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By Luke Lancaster Alleged images of the iPhone 7 point to a second row of speakers and a larger camera, but that doesn’t entirely agree with other leaks. …read more
Source:: http://www.cnet.com/news/iphone-7-speaker-leak/#ftag=CAD590a51e
