lgeek

14 ms·

91.
by lgeek 12y ago
> Apple, Samsung, and Qualcomm have locked up the handheld arena. Not really. Many low end to mid range devices use Allwinner, Rockchip, MediaTek or Amlogic SoCs. NVIDIA's Tegra series has also been somewhat popular and the two K1 S
92.
by lgeek 12y ago
I guess my definition of going nuts was a bit more conservative. Both x86-64 and ARM's AArch64 currently only use 48 bits for virtual addressing. Still, even if you design for computers with 256GB (2^38) physical memory, you still ha
93.
by lgeek 12y ago
I don't know about this particular project, but the standard approach is to use a PID controller, which uses the derivative term to control overshooting and oscilations.
94.
by lgeek 12y ago
Yep, I think this is the correct answer for the general case. With structures close to or larger than a page and on 64 bit systems you can go nuts with overallocation because the virtual address space is much larger than the amount of physi
95.
by lgeek 12y ago
Maybe it is more complicated as a concept, but the implementation is much more simple. They're using a MCU with integrated radio, it's almost free to add the RF source to the base system only using the avalanche diode. A HV geiger
96.
by lgeek 12y ago
> ldd actually executes the program being probed; It's insecure, but it's actually a bit more nuanced. What I'm describing applies to up-to-date glibc, it might have been even more insecure in the past. ldd first calls the
97.
by lgeek 12y ago
The diagram showing the stack on program entry misses the auxiliary vector[0]. As a sidenote, I find stack diagrams more intuitive (for typical descending stacks) when the low address is drawn at the top. This way it looks like a real-world
98.
by lgeek 12y ago
What superscalar and out-of-order processors are exploiting is instruction level parallelism, while their technology seems to use thread level speculation. > Without knowing the details on how they compiled the SPEC benchmark it's
99.
by lgeek 12y ago
I'm going to remain skeptical until they publish more details. The report[0] linked from their homepage seems to contain more/better information, but it's not much. What seems pretty clear is that they use a proprietary ISA a
100.
by lgeek 12y ago
Leaded solder has better wetting properties, it can be soldered at lower temperature and it's more reliable for joints exposed to any mechanical stress, including from vibrations and thermal stress. Any way you put it, it's superi
101.
by lgeek 12y ago
No, I did not use libhybris. It boots the kernel I've patched and it uses a full Linaro filesystem on a micro SD. The Android FS is not even mounted when running GNU/Linux. The SoC is RK3188 and it uses a proprietary bootloader to
102.
by lgeek 12y ago
Sorry, but that looks more like an artist's vision of a die shot than an actual die shot. The TRM is pretty clear that it's an A15: http://i.imgur.com/Fvh2KVT.png
103.
by lgeek 12y ago
I did a long weekend project a few months ago bringing up GNU/Linux on a low cost tablet. Here's a picture of it running XFCE: http://i.imgur.com/jmh8N0W.jpeg If you at least have a kernel source for the SoC, it&#
104.
by lgeek 12y ago
The companion core of the ARMv7 TK1 is a low power Cortex-A15, like the grandparent comment says. This is different from ARM's big.LITTLE which uses different microarchitectures for the two clusters, i.e. Cortex-A15 + Cortex-A7 or Cort
105.
by lgeek 12y ago
> If your device has full disk encryption using a strong password, physical access doesn't get you much in the way of accessing the data. Well, even if assuming that all your software is bug free, someone with physical access can ei
106.
by lgeek 12y ago
> why bother I'm mostly working on software for ARM and since all the tools I need for work run well enough, why not? I still use x86 at home. > which ARM machines have you been using as desktop replacements? The ones I've u
107.
by lgeek 12y ago
I've been using ARM machines as a desktop replacement for a few years now. Native applications run just fine on fairly modest hardware. However, for web browsing, a quad core Cortex-A9 around that frequency and with a 32 bit DRAM inter
108.
by lgeek 12y ago
I don't see FPGA acceleration being useful in mainstream computers soon. By the way, AFAIK the one in Novena is primarily intended for data acquisition, not acceleration. FPGAs are generally good for accelerating data-parallel applicat
109.
by lgeek 12y ago
> Some people tested the claims (using a DSLR with the infrared filter removed I don't know if the video is faked, but that is a horrible way to test the claims. Regular image sensors only detect near-IR and not the mid to far IR ra
110.
National Express print-at-home vulnerability(ifc0nfig.com)
7 points by lgeek 12y ago|0 comments
111.
by lgeek 12y ago
> I like that all processes run in CPU ring 0 and safety is ensured by the VM. It seems like this is more flexible This approach has a few issues which make it impractical for use by a real general purpose OS: * it moves all work related
112.
by lgeek 12y ago
Narishma's sibling comment is spot on: the microcontroller profile cores have a subset of the instructions available on application profile cores. Cortex-M0(+) and Cortex-M1 have a base set of instructions, while M3, M4 and M4F each ad
113.
by lgeek 12y ago
What do you mean by 'versions of ARM assembler'?
114.
by lgeek 12y ago
Yes, it's pretty outdated. It looks like it was written for ARM7TDMI which is ARMv4T. It seems like a decent introduction to RISC assembly programming though. This sort of stuff can get you started, after which you can get up to speed
115.
by lgeek 12y ago
Yes, and as jmpe said they have quite a few SoCs without NEON (I think basically everything apart from ARMADA 1500 plus). They seem to be targeting devices like smart TVs and STBs nowadays, so I guess it's not a big deal.
116.
by lgeek 12y ago
> architectures that don't support NEON (they often lack them in Marvell and Allwinner). I'm probably nitpicking here, but: * All Allwinner SoCs have NEON[0] * Most current ARMv7 processors have NEON. Of the current ARM cores,
117.
by lgeek 12y ago
I generally want an almost complete TRM too. In my experience there are many more SoCs with an available TRM than with complete support in the mainline kernel. By the way, there some WIP work for getting RK3188 support in mainline. It can b
118.
by lgeek 12y ago
> Just ask the hard kernel / odroid guys - they have eight cores Of which you can only use 4 at a time because Exynos 5410 is broken. > at about the same price point. 69% more expensive.
119.
by lgeek 12y ago
On ARM SoCs you generally can't really talk about 'the GPU'. There are separate: * 3D accelerator, which is what some people call the GPU, but it only does 3D acceleration (OpenGL ES in most cases) and on newer models it can
120.
by lgeek 12y ago
I've been hacking Rockchip RK3188-based devices for a few months now. What caught my attention are the low cost Android PC-on-a-stick and tablets using this SoC. We're talking about $50-ish delivered for a PC-on-a-stick with 2GB o

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