Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror

Comment What about aliens? (Score 1) 407

There is a low level but prescient rumor in some area that aliens are damaging windshields in cars. Go look at the windshield of your car and see if there are hundreds of little pits in them.

The pits change the characteristics of the light heating up the inside of the car on a summer day enough that several automotive engineering groups have had to deal with it. Typically it means doing something different with plastic. One example is the plastic covers over those auto belt things in the mid 80s where the plastic was deteriorating faster in cars with more damage to the windshield was mentioned in a an article in an automotive safety journal. The pits also mean the glass gets hotter as it ages so the frame has to compensate.

A vast majority of the pits are caused by tires throwing small bits of rock at an angle to the glass. The small bits of rock also seem to be tracked in from far away and aren't from the local road surface.

So when the light output goes way down, will someone also blame the aliens?

Comment Re:Am I bad at sums? (Score 1) 115

How can you both over sleep and under sleep? And how can you ask that in a survey or get it from other data in a reliable way? I know this can be true but I expect about as many correct answers on a self survey to a question like that as "what color is the last unicorn horn you saw?"

There are people who both under sleep and over sleep but they are very rare and I expect they would be hesitant to answer the question correctly. That doesn't even deal with the issues of having them dropped from the pool of subjects due to other health issues.

Comment Am I bad at sums? (Score 2) 115

Of all participants, 31.2%, 36.9%, 21.4%, and 10.6% reported 0, 1, 2, and 3+ risk factors, respectively. There was a strong relationship between the lifestyle risk index score and all-cause mortality.

31.2+36.9+21.4+10.6= everyone and 1% extras. Did significant significance creep in?

Out of all 96 possible risk combinations, the 30 most commonly occurring combinations accounted for more than 90% of the participants.

Each of 7 factors can be one of two states. That is 2^7 except that two of the conditions are "too much" or "too little" sleep which means a those state can be reduced to one. 2^6 isn't 96 as far as I know.

Comment Re:I plan on ossifying (Score 1) 279

A problem with Category Theory under a different term was mentioned by W.L. Livingston in The New Plague where he describes what he calls Track A or Track B problems. Track A problems are ones that can be split into smaller problems by one person. Track B problems are complex enough that a single person can't keep enough details in their head to properly split them up into sub-problems. Tack B problems need far more resources and most often a signifignat amount of those resources aren't helping find a good solution. There is also the issue that what might be a Track B problem for me might be a Track A problem for you and I think Category Theory doesn't fix those core problems even as it provides a more formal way to approach a solution.

Comment Re:Not all coding requires the same skill set (Score 1) 397

Fortran, APL and Pascal all have ways of doing pointers and pointer arithmetic. They tend to be ugly but it can be done and it isn't as simple as C (or assemblie's), "Just make it an int and do whatever you want to it". Even early Basic's varptr was mostly used to load assembly code into programs but it was also used for string and floating point number manipulation.

Comment Re:It's not entirely a lie (Score 2) 397

The weed out programs worked well when you could drop a class an hour before the final exam but universities decided that wasn't a good idea for some reason so now there is an enormous stress on students to follow their course even if the weed out course said they shouldn't be in that field at all. Oddly enough these changes seemed to have come from the accreditation side of the teaching business yet mecreases the vaule of degrees.

My take is only about 1 in 100 people will ever understand how the machines work well enough to be great programmers. I want to be able to pick a page out of "The Art of Computer Programming" and have a prospective programmer explain what the page is talking about and why (or why not) the concept mentioned would be used.

Comment Re:Typical Liberal Thinking (Score 1) 109

Coal baseload power in Australia is about $25MWhr or about £12.

A major problem with shutting down coal plants in Australia is that the coal plant operators are the ones paying to protect the coal from fires. If they stop paying, it will catch fire and burn. There is a coal fire north of Sydney that has been burring for about 6,000 years. Not using the coal doesn't mean it isn't going to burn and it is much cleaner to burn it in a coal plant than in a coal seam fire.

Comment Re:They can save my TRS-80 tapes? (Score 1) 76

There are programs that will convert mp3 from cassette tape recordings into the raw bit stream and back to the audio again. That means you can plug your mp3 player into the cassette port of your TRS-80/IBM-PC/Vic or Apple and load the programs.

Can anyone read 9 track tapes in Melbourne Oz? I have one that needs read before all the bits go bad. Its a 6250cpi for maybe upto about 175 mbytes.

Comment Re:They still support OSX 10.6? (Score 1) 140

10.5.8 is the last version that will run on millions of PPC systems. They were mostly high end and fast systems when they were new and are still very functional. Many of those systems were handed over to other family members after upgrades and they are still out there working. Even the lifesaver machines from 1999 will run os x 10.5.8 and they are quite responsive enough to be useful when using Safari. They tend to get a bit bogged down with Chrome 21 or Firefox 16 but they still work. There are millions of old macs still out there that aren't ever going to get upgraded.

Comment An article with the proper use of zero-day? (Score 1) 121

I didn't think I would ever see another article with the proper use of the term zero-day. I expect when the NSA talks about zero-day they get the terminology right. An exploit the NSA discovers and doesn't use isn't a zero day until someone else start using it. Exploits they buy are most likely zero-day. Bugs found and reported to vendors but not used aren't zero-day if a patch arrives before an exploit. A real trick is knowing if a new exploit is being used and I think it is clear that the spooks might have an advantage in detecting that sort of thing.

Comment Re:what about git? (Score 1) 87

The entropy in hashes must be less than the entropy in the data or it isn't a hash. That means that a hash requires that there be collisions by definition. A good hash will minimize those but there will always be a risk.

When writing a program that requires a hash, I find it useful to gut the hash function so that if I'm using sha256, I set all the bytes except for one to zero so I see what happens with collisions and can test that functionality. It is amazing how many bugs I've found in protocol implementations by doing this with hashes and block cyphers.

A coder also needs to balance performance with the function of the code if it's cpu bound. Many web pages now spend more than half their load time doing the TLS handshake. If you decided you want to go beyond what the CPU supports, you can also find your code runs very slow. Say you want to run something like a hypothetical AES-1024. The hardware only supports 256 bits so you get a 10x penalty for that plus you have to deal with 4 times more bits so there isn't anyway the new code won't be less than 40 times slower. Sometimes it is just better to use a much faster weaker hash for some parts and a slower better hash for data intergrity. An example of this would be something like rsync or torrent where there are lots of little blocks and very fast hash is helpful but for a better hash can be used for sets of blocks. You can not count on the speed of a hash for security either. A cheap bitcoin USB device can do hashes 31,000 times faster than my workstation.

Slashdot Top Deals

Hotels are tired of getting ripped off. I checked into a hotel and they had towels from my house. -- Mark Guido

Working...