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Comment: Re:Not all that surprising... (Score 1) 131

Modern type safe languages have a lot going for them, but they don't solve the hard problems of concurrency. (n.b. purely functional languages allow easy parallelization of some mathematical functions, but do not solve the hard problem, either). Highly efficient threading, especially at the system level, is not made easier by type safety.

This instruction set extension offers transactional memory access, so a thread can begin speculative execution that modifies a block of memory, and roll back on a conflict, rather than stalling on a semaphore lock.

Comment: Re:Keratoconus (Score 1) 550

by thestuckmud (#47525217) Attached to: Laser Eye Surgery, Revisited 10 Years Later

If you look around, you can find eye surgeons performing corneal collagen cross-linking in the US. My doc works in Colorado. The basic idea is that the combination of riboflavin (vitamin B2) and UV light causes the corneal layers to bond more tightly to teach other. The stiffer cornea is likely to maintain a better shape, but the main advertised benefit is stabilization, preventing worsening of the keratoconus.

In my case, laser ablation was used to remove the corneal epithelium (outer layer of cells) so the riboflavin eye drops would more readily diffuse into the cornea. I was a good candidate for the procedure, with a relatively thick cornea, and the outcome was good. The experience was a also a lot more painful than I expected, but worth the suffering. My eyesight is now OK (neither terrible nor great), and I can now consider Lasik if I want.

Of course, Intacs (small rings inserted into the eye that circle -- and help shape -- the cornea) are FDA approved for keratoconus, but the approval is under a Humanitarian Device Exemption, meaning they have not been proven effective.

Comment: Re:hype (Score 1) 243

by thestuckmud (#47194993) Attached to: New Car Can Lean Into Curves, Literally
OK. Now you are just plain wrong. Please read about car suspensions. You can start with the wikipedia article on camber angle: "The inside edge of the contact patch would begin to lift off of the ground if the tire had zero camber, reducing the area of the contact patch. This effect is compensated for by applying negative camber, maximizing the contact patch area." [Wikipedia]

Comment: Re:hype (Score 1) 243

by thestuckmud (#47192959) Attached to: New Car Can Lean Into Curves, Literally

[Please read comments carefully before posting.]

I stated the fact that many suspensions attain desirable negative camber while turning as a consequence of body roll. That cars are set up for neutral camber when driving straight is not at issue. The interesing part is that this Mercedes rolls the opposite way, and I wonder what changes were made to suspension geometry to account for this.

Comment: Re:hype (Score 1) 243

by thestuckmud (#47191745) Attached to: New Car Can Lean Into Curves, Literally

On the contrary, body roll is, in my admittedly subjective experience, quite noticeable. I drive two cars, a typical family car and a sporty two seater. The difference is night and day. One can easily feel the family car "sway" into and out of turns.

Cars can gain traction in turns if body roll results in negative tire camber (especially on the outside wheel). I wonder if Mercedes has engineered a sort of reversed suspension to take advantage of this property. Or is that what they mean when they say the design is "not ... for increasing cornering speeds"?

Comment: Re:Move along nothing to see here. (Score 1) 56

by thestuckmud (#47100215) Attached to: Servo Stock 3D Printer Brings Closed-Loop Control To Reprap

200 steps per rotation is normal for motors. However, the drivers everyone is using do 16x microstepping, good for 3200 steps per revolution. Accurate steps per revolution. That's better then 4096 +- 2 steps.

No, those motors are not good for 3200 accurate steps/rev: Motor accuracy here is likely to be +/-5% (10% range), so ideal accuracy will be closer to 2000 steps/rev, but real world accuracy drops with increased microstepping resolution due to varying load and detent torques, stiction, etc.

The good news is that this level of motor accuracy is irrelevant here. All you really need to do is beat the required positioning resolution (likely on the order of a few mils). A 20tpi lead screw and 200 step/rev motor easily beat this without microstepping. You probably still want a microstepping driver, though, since it can prevent mid-band resonance in addition to other features.

Comment: Re:This act is highly illegal (Score 1) 322

by thestuckmud (#47094139) Attached to: Registry Hack Enables Continued Updates For Windows XP

What's illegal about it?

"Whoever ... knowingly and with intent to defraud, accesses a protected computer ... exceeds authorized access, and by means of such conduct furthers the intended fraud and obtains anything of value ... shall be punished ..." - CFAA (18 USC 1030).

That's what. (Disclaimer: IANAL and therefore don't know what I am talking about).

Comment: Bad Summary. (Score 4, Interesting) 237

by thestuckmud (#46855999) Attached to: Erik Meijer: The Curse of the Excluded Middle

The synopsis completely misses the qualification, made in the first sentence, that TFA is discussing "concurrency, parallelism (manycore), and, of course, Big Data". Purely functional programming eliminates some significant issues in this type of programming (while introducing its own set of limitations). Meijer's point is that mostly functional programming is not really better than imperative here

For other types of programming, mostly functional style (using multi-paradigm languages) can be very nice. At least that's my position.

Comment: Re:What happened to C#? (Score 1) 100

by thestuckmud (#46667589) Attached to: Microsoft To Allow Code Contributions To F#

F# and C# are both multi-paradigm languages, and are both built on top of the CLR type system. Functional style is more natural in F#, but C# has first class functions (and lambda), too. F# has loops and assignment, but nothing as powerful/abuse-inviting as the C-style for loop. Neither approach is the one true style.

If you believe the proverb, "library design is language design" [from Bell Labs? Was it Stroustrup?], then F# is a much different language from other ML variants as it has native access to Dot Net/Mono libraries.

Comment: Re: Isn't a drone the same as an R/C airplane? (Score 2) 136

by thestuckmud (#46183163) Attached to: These Are the Companies the FAA Has Sent notices To For Using Drones

According to this, the difference in the US is that recreational model aircraft are covered by FAA Advisory Circular (AC) 91-57, while Unmanned Aerial Systems require either a Certificate of Waiver or Authorization (COA) or Special Airworthiness Certificate in the Experimental Category (SAC-EC). Operation in restricted airspace is another matter. In all cases, a pilot in command must maintain control of the aircraft (which I take to mean line of sight is required).

The other agency US unmanned aerial systems (UAS) have to contend with is the FCC. There are frequencies available for recreational RC use, and amateur radio bands, but last time I checked there was nothing for controlling a commercial UAS.

+ - How to Get Help Online (2013 Edition) 5

Submitted by Shlomi Fish
Shlomi Fish (3362) writes "The document How to Get Help Online (2013), aimed at inexperienced and not too net-savvy people, aims to summarise and spread the knowledge, of where and how to get help with one’s problems (especially technical and software-related ones). While many Slashdot visitors will not gain many new insights from it, it may be useful for them to recommend less experienced people to read it. Furthermore, its Creative Commons licence (the CC-by-nc) allows others to reuse it and build upon it. And comments and suggestions for improvements are welcome."

Comment: Re: Video editing... (Score 1) 501

by thestuckmud (#45778753) Attached to: A Flood of Fawning Reviews For Apple's Latest

I'm just going by reviews that use superlatives like "insanely quiet". Apple claims an impressive 12bDA at idle, which is going to be hard to hear even with the unit on top of a desk, but it is easy to turn the fans off at idle. I am assuming that the unique thermal design is really being exploited to minimize fan noise.

I disagree that about the competition being "very quiet". Quiet in a relative way, sure, but not as quiet as I would like. For reference, consider the recent Xeon powered HP workstation (non-liquid-cooled) under my desk for reference. It is actually quite nice compared to the screaming hair dryer fans of old, but, under load, the whooshing of air through it is plainly audible even with a gas fireplace fan blasting away 2m from my ears. Turning off the HP under these circumstances gives me a sense of relief from its noise. Compare that with this description: "during an Apple demo, a high-end Mac Pro, complete with upgraded processor and graphics cards, was live-rendering multiple 4K videos, and we couldn’t hear the fan over the normal room noises."

Comment: Re:Expensive Garbage Can ? (Score 1) 501

by thestuckmud (#45777625) Attached to: A Flood of Fawning Reviews For Apple's Latest

I guess if ... you don't know about hard drive failure rates, then it could be an attractive choice.

What hard drive? These come with SSDs.

Personally I don't like anything about it except for the dual-gpu support.

By all means choose a computer with the features you want. For my part, I think I've finally found a serious computer without distracting fan noise.

Another megabytes the dust.

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