How has OS X's "multi-userness" helped organizations?
Do you literally mean two or more people using the same Mac?
Has it been useful for organizations that users can ssh into Macs? Or is Apple Remote Desktop involved? (Does Apple Remote Desktop even allow 2 people two use two instance of OS X's GUI at the same time?)
Or by "multi-user" do you refer to the services that can be enabled using the "Sharing" pane of System Preferences (e.g., file sharing, printer sharing, remote management, internet sharing)?
I mean that BeOS didn’t have a way to login as separate people and use the same computer at different times with a clear separation of access rights. Mac OS X did, like most Unix or Unix-related OSes.
It’s not about simultaneous use, but standard user management, access control, and permissions.
Though yes, technically this also allows multiple to access it simultaneously via ssh and other things that’s not the important part for IT in this instance.
But a duplicate of the actuator failed in a lab on Earth after almost exactly as many turns as the actuator in space lasted -- that's how they determined the cause of the spacecraft's going offline.
True, but that confirmed the test run in space, not the other way around. It may have be hard to know in advance if 348 failures on Earth is representative of space, especially because it wouldn’t just be that one system. It would have been lots of parts built in to system working together.
Original mission for Voyager 2 was Jupiter and Saturn fly-bys which was mostly a success. The idea is to engineer parts to survive the mission and maybe go a bit further if you aren't at a point of diminishing returns in regards to cost. If it costs $1000 for a 10% gain in life of part, maybe go for it. $1M for 10%? Maybe not. Additionally, gamma radiation can do some weird things to materials and can effect things differently depending on dose rate. Lubricants can increase in viscosity and acidity under gamma. Radiation effects on spacecraft was not as big of a deal back then. Missions were short and electronics weren't small enough to have noticeable radiation effects.
As far as I'm concerned, this is akin to suggesting you shouldn't back up the data on your computer because it distracts from protecting your working installation. You can do both—invest in a back-up strategy, while investing more money and vigilance in protecting the primary source.
Space exploration is more though, because not only is space exploration an investment in a back-up plan, it brings very real benefits home to earth. The whole point of exploration is that you don't know what you are going to find or what the repercussions of what you find will be.
>[Bitcoin] only appreciates if you can talk other people into believing it's worth more
I would say the same about gold (though you probably disagree). Gold has some "intrinsic value" (e.g., as a plating on electrical conductors) but would be worth much much less if no one believed that it is a good way to store money.
But perhaps more importantly, Bitcoin differs drastically from most fiat currencies in that its rate of inflation is capped: over 85% of all bitcoin that will ever be created have already been created.
The same BTW cannot be said of gold, which is being mined at an increasing rate:
Do you believe a religious metaphor to be useful for understanding climate change?
Do you believe adding CO2 molecules to the air to be intrinsically sinful with the result that no amount of subsequent removal of CO2 can wash away the sin?
Sure, but CO2 removal can be funded otherwise than by
CO2 offsets or carbon credits -- by a tax on fossil fuels, for example. It is even possible that research can be targeted at using the carbon removed from the atmosphere for fuel or for production of plastic. Burning the carbon (again) as fuel results in no net reduction in atmospheric CO2 of course, but it would probably replace fossil fuels (just as any other renewable source of energy would) and if it ever looks to become profitable, then that would tend to cause increases in the efficiency of CO2-removal tech at no expense to the taxpayer with the result that any CO2-removal efforts not funded by profit-motivated fuel production (e.g., taxpayer funded CO2 removal) become more efficient.
But my main point is that global warming is eminently amenable to technical solutions similar to how for example putting humans on the moon was eminently amenable. Not all societal concerns are so amenable, but for those that are, it seems to me very suboptimal to resort to analogies with religious concepts in public discussions of the concern.
My first comment has a score of -4 now by the way.
Funnily it works both ways as indulgences were supposed to "wash away the sin".
Also, I would have hoped that we could have managed to solve the pollution issue in a rational way, but hope is getting thin. And religion comes with the power of strong taboos that might succeed where we previously failed. Or maybe what is blocking us is how progress has been given the status of a new religion, and while we can appreciate where it got us, we also have to consider whether the costs aren't going to outweigh the benefits in the future...
It's surely possible to take too much, but it's a lot. A typical over the counter tablet is 500-1500 IU of Vitamin D. Here[1]'s a study giving an oral dose of 100,000IU to a hundred people, and here[2]'s a paper suggesting muscular injections of 600,000IU in 10 people showed no evidence of metabolic abnormality. The Mayo Clinic[3] site says:
> Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day.
That's 100x the recommended dose, every day, for months. Were you using powdered vitamin D instead of protein powder by mistake or something?
Deva Boone’s blog (an MD featured often on HN) describes a case where an extra 5000IU supplement caused neurological problems.
IIRC, there was no regard to other sources - e.g. she might have gotten 30,000 other IU per day from Milk and another amount from fish. Very unlikely - much more likely that something else made it toxic in that case.
Regardless, it is clear that the upper safe limit has significant variance and is not well characterized.
(Personally have been on 10,000IU daily for the past 7 years with no ill effects and possibly good effects, n=1 standard disclaimer)
How much a person can take without producing symptoms varies. My threshold was much lower than average probably because of chronic infections, e.g., Lyme disease.
Anyone taking substantial doses of vitamin D (>2000IU daily) should probably be getting regular blood tests to monitor their vitamin D levels. Vitamin D can accumulate in fat and the liver.
