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Comment Re:Should have stayed old school (Score 2) 174

LEDs most certainly can be "partially on", by regulating the current through them rather than operating at a fixed current (and thus fixed voltage). There are ICs that do that, e.g. the On Semiconductor CAT4016, though that is used for indicator LEDs rather than high-power illumination.

LEDs don't even have a specific "fully on" current. They are specified by their manufacturers with a maximum continuous current, but that isn't "fully on". The specifications also give a maximum pulsed current at some particular duty cycle, but that isn't really "fully on" either, because the maximum achievable current may be higher with a lower duty cycle. It's not clear that "fully on" actually has any specific meaning for an LED.

It's less expensive and more efficient to pulse-width modulate LEDs than to adjust the current, so pulse width modulation is definitely the most common way of varying LED intensity.

Comment Google announces new Micro USB-C connector (Score 1) 127

That's the most impressive part of the announcement, if you ask me. Their store page says that they have a "USB-C to USB-A adapter", which is nothing special, but also a "Micro USB-C to USB-A connecting cable".

I'm eager to hear when this new "Micro USB-C" connector will start appearing on Android phones and tablets.

Comment Don't blame the FCC (Score 1) 147

If you think radio jamming should be legal, your issue isn't with the FCC, it's with US law, specifically 47 U.S.C. 333. Complain to Congress.

Despite that these and other jammers would have some beneficial uses, in my opinion it's a very good thing that radio jamming is illegal (with some exceptions for law enforcement and national security). Legalizing radio jamming in any form would cause far more problems than it would solve.

Comment Not all Li batteries are prone to thermal runaway (Score 1) 99

Lithium iron phosphate (LiFePO4) batteries are considerably more stable than lithium polymer and are not prone to thermal runaway.

They have somewhat lower energy density than lithium polymer, which is probably why they're not very common for phones, tablets, and laptops. They were used in the OLPC.

They are also somewhat common in RC cars and planes, in part due to their voltage (3.2V, so four series cells make 12.8V), and in part due to their higher possible discharge current.

Submission + - Visual ARM1 - Celebrating ARM's 25th Anniversary (visual6502.org)

trebonian writes: Today is the 25th anniversary of ARM Ltd., UK. To celebrate and honor their amazing work, we present the Visual ARM1, created in collaboration with some of ARM's founding engineers.

Designed by Sophie Wilson and Steve Furber before there was an ARM Ltd., the Acorn RISC Machine was the first of a line of processors that power our cell phones and tablets today. Unlike our projects based on microscope images, the Visual ARM was created from a resurrected .cif chip layout file, used under our license agreement with ARM. We also photographed one of the few ARM1 chips at very high resolution, and our photograph is featured at the Centre for Computing History in Cambridge.

Credit goes to ARM founding engineers John Biggs for inspiring the project, discovering the tape, and recovering a usable .cif file, Lee Smith for spotting the variable record format used to encode the file (an artifact of the VMS on Acorn's VAX that at first appeared to be widespread corruption of the file), to Cambridge University Computing Services for reading the Exabyte tape, and to ARM founder Dave Howard for help unraveling the VLSI CIF dialect. Our chip simulation and visualization was developed by Barry Silverman, Brian Silverman, Ed Spittles, and Greg James.

Comment TSX fixed? (Score 1) 78

TSX was disabled in Broadwell and early Haswell chips due to a bug. Do these new Broadwell-U have the TSX fix?

I have an experimental workload for which TSX would be very helpful, due to a need for atomic reads and writes of unaligned 10-byte data items. As far as I can determine, x86 provides no other way to guarantee atomicity of an unaligned 10-byte read or write.

Comment Re:True inventor of blue LED not awarded Nobel eit (Score 1) 276

Perhaps. IEEE Spectrum credits Maruska, as do several other histories of the subject.

http://spectrum.ieee.org/tech-...

Maruska seems to have made the first working violet LED. Some people claim that it doesn't qualify as a blue LED, but as far as I know there's no agreed-upon hard distinction between violet and blue. Maruska developed the right materials and process to make it, even if RCA pulled the plug before he had solved all of the problems necessary for commercialization.

Comment Re:Pricing? (Score 3, Interesting) 47

$49 only gets you the Edison module, which is useless by itself. You also need a base board of some kind. The Edison module with the Arduino-compatible base board shown in the photos will set you back $99. Still a pretty good price. 3x more expensive than a Raspberry Pi, but it is a lot more capable.

I'd get more excited about a 64-bit ARM embedded board, but those aren't available yet, other than a $6000 development board from ARM.

Comment business model (Score 2) 34

Not all of the code on GitHub is open source, but the majority is -- handy, when that means an account is free as in beer, too.

I'm not privy to any details of GitHub's finances or business model, but most likely it's a good thing that there are non-open-source projects using GitHub, because that's probably what's paying for the free open source use. I've recommended to several clients developing proprietary software the use of GitHub rather than running their own in-house repositories, because the interface is easier for them to use and they don't need as much in-house expertise to manage things. Because Git is distributed, they could of course do both, or easily transition away from GitHub later, and that's a selling point.

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