Forgot your password?

Comment: Re:Three duh's from the article: (Score 1) 37

by MightyMartian (#47581715) Attached to: Multipath TCP Introduces Security Blind Spot

Christ, it was one of the first lessons I learned that one could not simply sniff incoming packets and assume there was any order to them. People have been writing UDP protocols for decades now that require reassembly of packets into proper order.

I get that multipath TCP means a lot more traffic will be sent in odd fashion, but really, if the recipient TCP stack can grab and reorder them, then that's what counts.

Comment: Re:Hmmm... (Score 1) 164

by fuzzyfuzzyfungus (#47575625) Attached to: Quiet Cooling With a Copper Foam Heatsink
Fabrication costs eat you alive if you try to approximate a fractal too closely; but that is essentially where the later generations of solid metal heatsinks were heading before heatpipes hit the scene.

In the cheapest and simplest incarnation is just a beefy heat spreader plate on the bottom to ensure that each fin gets a reasonable connection to the heat source. In fancier versions, the spreader also extends vertically to help transfer heat to the more distant parts of the fins.

Recent AMD retail heatsinks use a clever design (cheap, because it's an aluminum extrusion with just a couple of cuts for the retention clip; but a combination of fins for surface area and bulkier conductive struts to feed the fins): image. The central slug is about the same size as the CPU heat spreader, and is solid throughout except for the slits for the retention clip. The longest fins are the ones directly attached to it. The four thicker struts on each corner support shorter fins(longer close to the base, shortest at the edges where there will be the least heat available for dissipation).

Heatpipes are superior enough to just about any solid material(with the possible exception of diamonds and carbon nanotubes; but those aren't really options) that most of the more expensive coolers have moved to 'heatpipes as close to the CPU as possible, loads of sheet metal fins with the heatpipes running through them' design; but you can definitely see the tradeoffs between surface area and conductive cross section in today's cheaper extrusion designs and the last generation or two of pre-heatpipe enthusiast gear.

Comment: Re:Er, that's a bit confusing (Score 1) 161

by fuzzyfuzzyfungus (#47570597) Attached to: The Problems With Drug Testing
Honestly, that's the bit that surprised me. If the payoff exceeded the potential legal exposure I don't doubt that you'd be able to find contractors willing to vivisect the homeless; but I am surprised that 'studies' on such a population(heavily weighted as it is with potentially confounding mental and physical morbidity, difficult to track over anything but the short term, etc.) would be treated as adequate.

From what friends in biology tell me, I gather that the reviewers would spit on you if you tried to do a rodent study by 'eh, we set out a nonlethal trap in the basement of the building and used whatever mice wandered in'. Obviously you can't order custom humans the way you can standardized mouse strains; but impoverished homeless people seem like about the least desireable study population you could imagine, except for the cheap and highly unlikely to sue you bit.

Comment: Hmmm... (Score 4, Insightful) 164

by fuzzyfuzzyfungus (#47568467) Attached to: Quiet Cooling With a Copper Foam Heatsink
With finned heat sinks, one of the limits on size was that the comparatively low conductivity of the fin material made surface area increasingly unhelpful as you got further from the heat source. Especially with paper-thin lightweight aluminum you could just keep making them bigger; but much of the fin would be essentially wasted because the delta-T between the more distant areas of fin and the source of the heat would be so high. Plenty of heat exchange surface; but not much heat making it out that far.

This is why more or less all contemporary heatsinks started embedding heatpipes some time ago, since that was the only way to get a reasonable amount of heat to the more distant parts of the heatsink.

This 'sponge' is more aesthetically interesting; but I see a lot of surface area that is only tenuously connected to the actual heat source. Newer Intel silicon just doesn't pump out the watts the way the old stuff did, so it might actually work; but I'd be shocked it if works any better than a much more prosaic heatpipe-and-fins design.

Comment: It Depends (Score 4, Interesting) 341

I've set up networks where the server infrastructure itself is on its own segment, so there's no need for firewalls between the servers themselves, but the whole subnet is firewalled by a border router.

A lot depends on how tightly you can lock down a server. On my *nix boxes, I tend to only run daemons with listening ports to the extent absolutely necessary. I have a LAMP server that basically has ports 22, 80 and 443 open, and everything else either shut down or set to listen only on Do I really need to configure iptables?

Comment: Re:I must be the outlier (Score 5, Insightful) 231

by fuzzyfuzzyfungus (#47564923) Attached to: Comcast Confessions
Not really an outlier, its a difference between cancellation on the phone and cancellation in person. The phone drones (or "the lost and the damned") are extraordinarily closely scrutinized and their paychecks and/or not getting shitcanned are directly dependent on 'retention'. The in-store people, apparently, are paid to be in store but not directly induced to hassle you.

I'm not quite sure why Comcast hasn't emiserated the in-store situation yet; but apparently they haven't, and it's not as though the front-line peons are fucking with you for their pleasure, so if they aren't forced to they generally won't.

Comment: Re:Little Appliance Parts (Score 1) 62

by fuzzyfuzzyfungus (#47564441) Attached to: 3-D Printing Comes To Amazon
I suspect that, at very least, 3d printing servics will be harassed (like youtube vs. the music labels) about this possibility, and some users will definitely try it.

The one thing that(as much as it surprises me) makes me a trifle skeptical of the lethality is that doing resin(or wood's metal or similar alloys if you want some extra weight and don't mind a little cadmium) castings from figurines isn't rocket surgery, especially for people with enough interest and fine motor skills to paint the things, and I've not heard anything about major disruption from that.

3d printing will lower the bar, since you don't actually need the master to create a mold from; but even if you exclude clandestine trade in cloned figurines, people could easily buy enough parts to copy an acceptably varied army for much less than they could buy the entire army.

Comment: Re:Astrobiology (Score 3, Informative) 39

by MightyMartian (#47561641) Attached to: Enceladus's 101 Geysers Blast From Hidden Ocean

And what would you define something that didn't ingest, metabolize, excrete, reproduce and have some sort of system of heredity? Other chemical processes; like fire and crystallization, might hit some of these marks, but we don't call them living systems. So while the precise chemical processes, heck maybe even many of the chemical elements involved may be different (silicon-based life on Titan or something like that), I think at the end of the day if it going to be called life, it has to have the same basic features as terrestrial life.

Comment: Re:Little Appliance Parts (Score 2) 62

by fuzzyfuzzyfungus (#47559565) Attached to: 3-D Printing Comes To Amazon
Amazon's offering is substantially less flexible than that of existing players (shapeways is the name that comes to mind; but there are others), who already accept basically any STL that isn't horribly munged in some way and spit the result out in a number of different materials.

You still have to model the part, or buy a (currently rather expensive) 3d scanner to do it; but if you are willing to put on your CAD hat, you could have the part by next week, just not from Amazon. I wonder if they are just moving slowly, or worried about the copy cops coming after them once people start knocking off action figures or something...

Comment: Re:Strength (Score 1) 62

by fuzzyfuzzyfungus (#47559531) Attached to: 3-D Printing Comes To Amazon
It lacks the sci-fi appeal of pure printing; but there are a variety of techniques that use the 3d printed part as the first step and then subject it to additional treatment steps in order to make up for those sorts of deficiencies.

As long as the subsequent processing steps don't change the dimensions(or change them in predictable ways that you can compensate for) you can get away with whatever tempering, annealing, and so on your application requires.

The trouble with the rat-race is that even if you win, you're still a rat. -- Lily Tomlin