* Posts by Chemist

2596 posts • joined 24 Mar 2010

While USA is distracted by its President's antics, China is busy breaking another fusion record

Chemist
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Re: let me guess...

"Fusion reactors produce fast electrons, which can be used in a classic breeder design (in fact they are too fast - you have to slow them down a bit somehow)"

I think you intended to type neutrons

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Chemist
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Re: Crazy ideas?

"The Greeks knew the world was around 2,000 years ago AND could prove it with math and physics."

And, as I've pointed out before, anyone seeing ships disappear slowly over the horizon and reappear or who has climbed a mountain and seen that mountains on adjacent islands do the same could draw the same conclusions.

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Constant work makes the kilo walk the Planck

Chemist
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Re: Isn't there a risk ...

"I know that the speed of light can very by medium,"

It is the velocity of light in a hard vacuum that is the constant.

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Elon Musk reveals Mars colony rocket capable of bringing pizza joints to the red planet

Chemist
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Re: Plenty of oxygen on the Moon

"and give it some plants. "

I point out that plants need many things, oxygen being one. Although they generate oxygen in sunlight during the dark they actively require oxygen. All plant culture will have to be indoors for many reasons.

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Chemist
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Re: What about Oxygen?

I'm not saying the chemistry is wrong it's not. I'm questioning the overall efficiency when the supply of energy is going to be limited. Given it will have to be solar or nuclear to run this lot I question how much kit they'll need. The Sabatier reaction, to produce the methane itself is exothermic once initiated but extracting or concentrating the necessary oxygen and then liquifying it will require a lot of energy.

For example to produce 1kg of hydrogen gas by electrolysis will require ~~ 60kW.hrs in the process producing 8kg of oxygen. To liquify the oxygen (for storage and engine use) needs ~~ 5kW.hrs for the 8kg.

I note some of the NASA papers don't actually mention the energy requirements

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Chemist
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Re: What about Oxygen?

"the production of fuel from simulant Martian atmosphere has already been tested"

I've no problem with the possibility of obtaining fuel ( from CO2) from the atmosphere it's the extraction of oxygen from a very dilute mix of other gases that I suggest will be a very energy intensive process. Probably better to produce hydrogen & oxygen from any available water even though that will also be very energy consuming esp. to produce/store liquid oxygen

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Chemist
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Re: What about Oxygen?

"- Sufficient, even in the atmosphere, to get things going on Mars,"

There are only trace amounts in the atmosphere. ( it's about 0.1% of an atmosphere that is already very low pressure (~0.6% cf. earth )) It would need to be generated from water or some other source.

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Raspberry Pi sours thanks to mining malware

Chemist
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Re: Bah!

"What you are suggesting is to give up altogether and just resort to reactive security. Both approaches are needed."

No I'm not I'm suggesting that at the present time ( and for how much longer ) we still need to be very careful about security.

"Well, in future I'm going to ask any one I give a lift to whether they can drive or not. 'Can't drive - you're out of luck, can't come in my car'."

That's just nonsense. It's totally irrelevant most of the time if other occupants can drive or not but I'm guessing that you'll need one for quite a while.

"We can design machines where this is just not allowed and a whole large category of attacks goes away."

Well until we do and they become the norm it doesn't matter in the slightest.

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Chemist
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Re: Bah!

"Now we are close to having self-driving cars. What you are saying is that passengers in such a car should not only know how to drive that car,"

Of course they'll need to able to drive - I guess it will be years before self-driving cars become trully autonomous

"We can program computers to do anything - why not stop security attacks "

You must be having a laugh now. The one thing we know is that bugs exist - where have you seen a software system that is perfect. (see the point about cars above"

"Hacks are very, very sophisticated"

Some are, some are trivial or even accidental . Many of the big 'hacks' have been by people with little skill but a lot of persistence.

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Chemist
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Re: Bah!

"Passengers on the train don't need to train as a train driver in order to catch the train."

You miss the point. Any group of people using a particular technology need some in-depth knowledge to use it safely. I did, by the way, include driving a car which is a near ubiquitous 'skill' which in most places requires examination.

I don't expect the average user to be a security expert just to have an awareness of the basics od on-line safety. You certainly can't expect the technology to cope with all the diversity of attacks from the sophisticated to the banal.

On the other hand if you want to do something more unusual, but still reasonable, like give yourself access to your home network from outside then you do need to understand what you're doing or take advice.

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Chemist
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Re: Bah!

"While I encourage people to understand all levels of computing, it should not be necessary - and if it is, we have not done our jobs properly."

The point is that it is necessary however much you'd like it not to be. I don't think I'd be too happy with an unskilled bus/car/train driver.

And that's before we take into account simple scamming/phishing by computer/phone or mail. We can't design/legislate for a risk-free world - people have to have an awareness of risk whatever activity is undertaken.

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Chemist
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Re: Bah!

"Computers are now widely used because we don't demand that end users need education to run systems correctly. "

Computers are now widely abused because we don't demand that end users need education to run systems correctly.

But seriously, at the present time no computer can be considered 'safe' without the user having some knowledge of the risk - no different to the rest of life really.

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Re: Bah!

"Now playing around with Pi is great for hobbyists and nice a cheap. You can load Linux on it. But keep it off the net and don't use it for serious work where you need security."

Are you really suggesting that using a Pi properly is in any way riskier than anything else *?. Good practice is what is necessary (combined with updated software). No computer is likely to be 'safe' when used incorrectly. I use ssh to access my systems from outside ( and only ssh) through an unusual port with an unusual username and certificates to reach both a pi and x86 on my home network. I'm conscious that two points are worst than one so I'm planning to have the Pi as the only access point.

Connecting your system to the internet requires some knowledge - education is necessary to discourage naive users from doing so.

* commonly available hardware.

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Chemist
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Re: Captain Bodge-tastic speaking

"and within a few minutes there were failed login attempts showing up in the log"

I have a pi & my x86 fileserver both with ssh port forwarded. However I don't use the standard ports and both use rsa keys and indeed very unusual usernames..

My x86 server has had 1 login attempt in 10+ years. So although it is really sec. by ob. it cuts down the attempts by a huge factor as port 22 gets a few a day.

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Swedish school pumps up volume to ease toilet trauma

Chemist
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I started work at a very classy research centre.

In one loo the graffiti read :

"Ici laisse tomber en ruine tous les beaux arts de la cuisine"

( or something similar - it was nearly 45 years ago)

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Meteor swarm spawns new and dangerous branch

Chemist
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Re: I welcome our new meteor overlords

""... if they can flash cook a pizza for me!""

Get lots of smart cookies on this site

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Going to Mars may give you cancer, warns doc

Chemist
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Re: I suspect that ...

"We must ensure this does not happen."

Joking aside it seems very unlikely.

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Chemist
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Re: I suspect that ...

"My money is on the invention of better shielding. Eventually."

Probably not until politicians go boldly forth !

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Silicon Graphics' IRIX and Magic Desktop return as Linux desktop

Chemist
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Re: SGI

"was expensive, but beautiful kit all the same."

It was. We moved a large number of workstations over to Dell/Linux/dual Xeons from SGI in ~~2003 and saved a small fortune. As mentioned above little needed to be done in software terms.

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Boffins find evidence of strange uranium-producing bacteria lurking underground

Chemist
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Re: The usual baloney

"Have you actually read any of Prof Widom's sources?"

Oh yes and that made me even more dubious. The wretched story is so full of holes and bad science (if some of it can be called science).

As for Widom after reading some of his papers, some of his peer's comments and some from his students I couldn't comment. (for legal reasons)

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Chemist
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Re: Alchemy

"now, changing anything to approximately iron is probably easiest?"

But not too easy, eh ?

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Chemist
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Re: The usual baloney

"Friend said every new scientific idea is outlandish when first proposed."

You've still got to find a way to prioritize what you read and attend especially these days when any dingbat can 'publish' on the internet somewhere. Having been involved in peer review and also having friends who are currently reviewers I can say that we did/do our best to maintain standards in the chemistry, medicinal chemistry and biomedical journals we contributed to. Although by no means a perfect system it's much better than a free for all. One the other hand the e-pub in question cites highly dubious sources and is sponsored by its own author and as far as I can tell has never been published in a 'hard' journal. Nor is there any obvious evidence that any experimental work has been repeated.

New ideas that challenge the norm are hard to propagate which is why the standard of evidence needs to be so high. People are more likely to 'believe' high-quality, repeated and repeatable experiments even if they ( and any related hypothesis) challenge the status quo

(In particular one good piece of hard evidence beats any number of mere opinions)

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Chemist
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Re: " For example replacing a hydrogen with deuterium slow significantly (~~2 fold) at that point"

"I would expect a drug with certain parts of made specifically with Deuterium would also be pretty expensive."

No Deuterium is relatively cheap certainly as part of the overall cost of manufacturing drugs. 99.9% D2O is available from Sigma-Aldrich in 4L bottles for example. Cost ? ~~$1000/L in small amounts.

"a natural background level of it which will find it's way into the bulk raw materials chain for drugs." -very funny, you'll be mentioning the C13 & 14 next

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Chemist
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Re: The usual baloney

"And no, a paper on the Arxiv is not acceptable (because the Arxiv is non-peer-reviewed-self-published stuff)."

Worst than that publication requires a 'endorser' or some such which in this case was the lead author himself !

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Chemist
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Re: The usual baloney

"If you're interested in why "

I know why - that's the difference between us having studied hundred of xtal structures and modeled ligands binding into receptors.

"As to sucrose and saccharine, they don't come into this as they don't smell - they are sensed by the tongue, not by nasal receptors in the nose."

They are still sensed by receptors in both cases and my point still stands. Ligands can bind in multiple ways to receptors and still produce a response.

And by the way what is this 'quantum vibration' ? In the case of deuterium substitution I find no problem with it having a small but measurable effect.

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Chemist
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Re: The usual baloney

This paper is extra-ordinary and contains content that I cannot believe. Shellfish making enough Calcium to replace their shells etc. No, sorry if this were true this would have set the whole of Biology/Chemistry/Physics on it's head and it hasn't.

This makes cold fusion look quite reasonable !

( A lot of the 'evidence' comes from a guy called Corentin Louis Kervran who subsequently won an Ig Nobel prize for his 'work' )

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Chemist
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Re: " For example replacing a hydrogen with deuterium slow significantly (~~2 fold) at that point"

"Now that sounds like a neat diagnostic trick, provided you have a supply of Deuterium handy."

Indeed it is and has even been suggested for final drugs although I don't know of any that use it. Deuterium and indeed Tritium is widely used in pharma research. Deuterium oxide is widely used for NMR spectography as a solvent and admix to remove the signal from 'exchangeable' hydrogens

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Chemist
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Re: The usual baloney

"why cyanide smells the same as almonds"

You do know that crushing bitter almonds releases cyanide !

"Bitter almonds may yield from 4–9 mg of hydrogen cyanide per almond[36] and contain 42 times higher amounts of cyanide than the trace levels found in sweet almonds.[37] The origin of cyanide content in bitter almonds is via the enzymatic hydrolysis of amygdalin.[37]"

https://en.wikipedia.org/wiki/Almond

In fact the main odour from almonds is benzaldehyde which some people associate with cyanide. I can't smell hydrogen cyanide myself ( a issue for a chemist !) indeed a moderate percentage of people can't . But I can smell benzaldehyde !

I'm not sure why you think that molecules of different shapes can't elicite the same response - for example sucrose and saccharin or one of the peptide sweetners.

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Chemist
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Re: The usual baloney

"Jesus fucking Christ! Another downvote for referencing a reputable scientific publication. Where do you get your science from then? Christian Science Monitor or the Grauniad?"

I suspect the downvote might be because there's no suggestion in this paper that nuclear effects are possible. which is something that that was being suggested by the OP. So your ref. was to a non sequitur.

As a chemist I accept that all chemistry involves quantum effects and many enzymes probably utilize tunneling but I don't see chemical (& therefore) biological systems having nuclear effects although as I mentioned in another post isotopes of lighter elements can show chemical differences.

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Chemist
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Re: "Now if the bacteria absorbs U235 preferentially things could get interesting....."

"Physicists will tell you that there's no chemical difference between how different isotopes behave chemically"

Chemists would tell you a somewhat different story. To be fair it's only the lightest elements that show sig. differences. For example replacing a hydrogen with deuterium slow significantly (~~2 fold) the metabolism of drugs at that point

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Chemist
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Re: Explosives Residues

"What is even odder I think is that these bacteria have evolved specifically because of human activities, and done so within our lifetime"

Even if this were true, which is unlikely*, bacteria are very versatile. In ideal conditions they may replicate in ~~20mins. Any successful mutations will survive, originals being crowded out. Any unsuccessful mutations (probably the vast majority) will disappear. There may be many, many dead-ends in just a few years ( that we don't see) . It didn't take too long for bacteria growing in the warm, nutrient-rich cooling water from power station towers to develop considerable resistance to chlorine bleach.

* bacteria will metabolize all sorts. Even in humans p450 enzymes will readily metabolize materials they've never been exposed to before.

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LIGO physicists eyeball a new gravitational wave

Chemist
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Re: Two solar masses (in energy) escaped

"I really would love to hear an explanation from someone who really understands this stuff."

Can't claim to be any kind of expert but my understanding is that the energy is radiated away in increasing amounts as the masses approach - this fits with the waveform detected where the amplitude increases with time until the point of merger. Maybe it will need much improved sensitivity to explore the very interesting region of time during which the merger happens.

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Boffins play with the world's most powerful X‑ray gun to shoot molecules

Chemist
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Re: Astonishing.

"That said I'm not sure how common Iodine containing molecules are in biochemistry, although there's meant to be a lot of it in seaweed."

Not often found in drugs but 'heavy' atoms are often substituted into materials for x-ray crystallography to help in the process fr solving the structure. This is often Sulfur being replaced by Selenium in protein crystallography. As mentioned in the article damage by the x-ray beam to the crystals used is a major problem in obtaining high-quality structural info.

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Distro watch for Ubuntu lovers: What's ahead in Linux land

Chemist
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Re: FreeBSD wireless device support

""linux still has no support for the wifi driver ""

The advice to buy a usb wifi stick is quite valid - a number of makes are sold cheaply for older Rasp. Pis and work well on all the Linux PCs I've tried them on. As they are only ~1cm long when plugged -in they scarcely increase the footprint of a laptop.

The one I've got on a Pi (running Motion ) is :

Bus 001 Device 009: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter called a WiPi from one of the on-line Pi retailers

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Chemist
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Re: Printing

"commodity inkjets and lasers are only supported, if at all, by generic drivers."

Not here, not for years and years. My Samsung laser even came with a linux driver disk. I also have a cheap, Epson all-in-one scanner/ink-jet - that also is no problem neither the scanner or the printer.**

As for installation and control even the Rasp.Pis on this network can automatically find and install the printers.

**(Using OpenSUSE and installing the printers (by GUI) as network printers - no problem)

BTW for PC loaded with a variety of Linux point your browser to :

https://nimbusoft.com/

(Never tried them yet so can't comment)

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Don't rely on fitness trackers to track number of calories burned

Chemist
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If you'd like a (rough) algorithmn ...

from one who's struggled with weight over many years but succeeded in the end.

If you weight ~85kg ( otherwise scale it)

1 mile walking is 100 Cal ( almost any speed of walking)

1 mile running is 130 Cal

100 metres ascent & descent is 100 Cal All figures approx. and sorry to mix units but they are easy to remember.

So doing the ~12 mile round trip from (say) Zermatt (1600m) to Gornergrat (3100m) would be approx. 1200 Cals for the distance +1500 Cals for the height = ~2700 Cals or ~~ 2/3rd of a marathon.

The figures are accurate enough to give you some idea of the amount of effort needed to burn off all those goodies.

Other exercise is available but I don't have such well-used values.

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Gravitational waves permanently change spacetime, say astroboffins

Chemist
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"the Australian Research Centre of Excellence for Gravitational Wave Discovery,"

That's a hell of a title for any institute !

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HPE Labs manufactures monster memory Machine system

Chemist
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Re: @AC...

"To be fair... I don't see a lot of use cases where this is really needed."

I do

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Chemist
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Re: Hmmm what should we call it?

"I know... why not call it a 'Mainframe' ?"

Multivac ?

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Ransomware scum have already unleashed kill-switch-free WannaCry‬pt‪ variant

Chemist
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Re: Experts all giving advice how how to stay secure

"A lot of people (including myself) use their laptops in various locations. I prefer the "only enable services and applications that you need" "

I prefer the both approach

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Chemist
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Re: Experts all giving advice how how to stay secure

"I need to review what services it has enabled to make it a bit more secure before I connect it to the Internet to download latest patches."

Are you suggesting that the "internet" can get to your laptop's open ports - have you no router/firewall etc ?

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WannaCrypt ransomware snatches NSA exploit, fscks over Telefónica, other orgs in Spain

Chemist
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Re: Do you think the military run fucking ghey Linux?

"Do you think the military run fucking ghey Linux? "

There are plenty of documented refs. to the fact that they do ! A (few) examples

http://linuxgizmos.com/u-s-military-uav-control-systems-switch-to-linux/

http://www.zdnet.com/article/the-air-forces-secure-linux-distribution/

http://www.techrepublic.com/blog/linux-and-open-source/linux-grabs-its-single-biggest-win/

https://www.redhat.com/en/about/blog/red-Hats-decade-of-collaboration-with-government-and-the-open-source-community

BTW In the case of human viral protection one of the most important factors in resistance is biological diversity . Ditto with IT security

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UK hospital meltdown after ransomware worm uses NSA vuln to raid IT

Chemist
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" But it is an attack in the sense of a guy standing in a middle of street firing a machine gun randomly"

It seems more than just that - each bullet starts infecting as well . It seems to contain a worm using a SMB vuln.

(https://isc.sans.edu/)

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Chemist
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Re: Ransomware

"You don't lock them up and demand a ransom."

You might not now but in medieval times it was the best way of becoming rich

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Microsoft's Windows 10 ARM-twist comes closer with first demonstration

Chemist
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"Linux has been on ARM devices for a while"

More to the point Firefox, GIMP, Chromium and buckets of other stuff ( as you suggest entire Linux distros) have been native on ARM for quite a while.

I've been compiling a lot of my stuff from x86 to Arm for the last year ( and indeed now I'm now often writing/compiling programs on ARM and then moving those to x86.

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America's mystery X-37B space drone lands after two years in orbit

Chemist
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Re: it is unlikely that it carries any weapons... cough... cough...

"and I think the KE of 15kg at 18000m/s is about a thousandth of that."

Agreed [ 0.5*15*(18000^2) = 2.4e9 J]

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Fortran greybeards: Get your walking frames and shuffle over to NASA

Chemist
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Re: Accuracy and industry standards

"However, all of this only goes so far when you are dealing with intrinsically unstable problems. In particular, CFD is quite notorious for numerical instabilities and tendency to chaotic behaviour "

Well worth the interested reading about Edward Norton Lorenz's experiences with early computers and the 'butterfly effect' : https://en.wikipedia.org/wiki/Butterfly_effect

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You only need 60 bytes to hose Linux's rpcbind

Chemist
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"f you really need to run rpcbind (which binds RPC calls to addresses), put it behind a firewall limiting Port 111 to the outside world."

Does no-one scan their external address for any (inadvertently) exposed ports ?

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Chemist
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"it appears to be mainly used with NFS servers."

It is, both my NFS servers have it open but they are internal.

( The only ports I have exposed externally (via port forwarding) are ssh on unusual port numbers, with unusual user names ( just the one limited user on each machine) and certificates)

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