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Comments

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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Just don't try to write an OS in Java (507 comments)

Hi,

That is a different and also interesting case, and just by bringing it up you'd pass my test.

No, I meant something like:

public static final String CRITICAL_ID = "whatever"

in a secure API. If I use char[] instead what happens if a miscreant overwrites the content of the array; what BadThings might happen?

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Performance improvements have helped it survive (507 comments)

Except that once JIT/Hotspot is involved all or most of the executions *are* of compiled machine code, optimised to the particular CPU on hand and the particular data set for this particular job. So things like dynamic inlining *for this particular job* can allow the JVM to produce *better* machine code which will execute more quickly than statically-compiled code.

The translation takes time, but for long-running tasks that may well be easily amortised away.

So single-threaded Java can beat single-threaded C++.

But I can also bring more CPUs to bear on the code safely with Java for a given level of code complexity (well, now C++ finally has some sensible volatile semantics, that's a little less true).

And there are other factors such as the generally forced synchronous nature of C++ heap handling which can work against it.

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Performance improvements have helped it survive (507 comments)

I promise you that it was worth saving many MB in the .WAR and associated thumb-twiddling time, plus showing me in the logs which library and other routines were actually being used. I never felt the need to time stuff (since performance was at least not visibly worse). Shame on me!

If I get a chance I'll do as you suggest, though it'll be tricky with all the many things going on concurrently.

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:What is cool? (507 comments)

When has being a Java dev gotten anybody laid?

Umm, I don't think you're holding it right. WORKSFORME.

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Just don't try to write an OS in Java (507 comments)

My favourite related Java question to ask in the context of security is: "What's the difference between char[] and String, eg if I have one in a critical API as a public static?"

I'm quite happy to hear slightly 'wrong' answers as long as someone understands a little about wrapping/immutability and so on...

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Performance improvements have helped it survive (507 comments)

+1 for ProGuard; I use it for my main Java Web app and apart from anything else PG vastly reduces the size of the .war I'd otherwise have to ship.

Also, not all of my target hosts have a full server-class JVM/optimiser, so getting stuff done up front is a good thing.

Rgds

Damon

about a week ago
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If Java Wasn't Cool 10 Years Ago, What About Now?

DamonHD Re:Performance improvements have helped it survive (507 comments)

"WILL NEVER": gosh, not true and never has been unless you know the exact CPU and execution paths and data sets that you are compiling for, for all executions of the statically-compiled code. Please don't regurgitate this stuff.

When maintaining a C++ build system used internationally by a large bank I had to guess what the optimal target instruction set variant, cache line size, etc, would be over the lifetime of the output code, which was always a compromise over London/NYC/TOK/etc and a huge range of dev and production hosts of various ages. And with most/much of the library stack unsafe for C/C++ threading even though almost none of our machines (eg desktop or server-farm) where single CPU you could not then and could not now say whether C++ or Java would be necessarily faster on a given machine, given all the CPU- and run- specific optimisations the JVM has available to it that C++ does not.

I currently work on a Java low-latency high-frequency trading platform in the day job and an ASM/C/C++ based microcontroller platform for my start-up. And I think that I've been using C++ and Java for most of their existences, amongst other languages (I've been writing ASM for >30y); I have a fair idea of what is fast and what is productive.

Rgds

Damon

about a week ago
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Gas Cooled Reactors Shut Down In UK

DamonHD Re:EIGHT weeks??? Nukes need to be more modular. (120 comments)

Maintenance and refuelling is done when demand is low, eg in summer.

In the UK I don't think any nukes explicitly load-follow, unlike in France for example, though one (Sizewell B) could.

Rgds

Damon

about three weeks ago
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Slashdot Asks: Should Schooling Be Year-Round?

DamonHD Re:No, school should not be year-round. (421 comments)

You make me even happier with my 3-and-a-bit-days-per-week contracting job with most of the rest spent on my startup! %-|>

Rgds

Damon

about three weeks ago
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Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives

DamonHD Re:And when you include end-of-life costs? (409 comments)

Well, not entirely. Still has its own nuke, gas and (erk!) coal, at least for now. And still not enough interconnection to depend very heavily on anything outside its borders I suspect (I must look up those figures vs winter peak demand).

Don't get me wrong, I'm not against nuke at all, it's just not the panacea that is frequently claimed IMHO.

Rgds

Damon

about three weeks ago
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Slashdot Asks: Should Schooling Be Year-Round?

DamonHD Re:No, school should not be year-round. (421 comments)

Much (not all) of what they're learning at school is like scaffolding; they need to retain it to get to better things but not necessarily for its own sake after that. I've managed without various apparently-essential rote-learnt elements too. (I loved physics because you had to remember about 4 things to pass the exams, including inverse square law and Ohm's law; I hated biology at times since it seemed to require lots of meaningless memorisation of things best looked up when actually needed.)

But if they drop that scaffold too quickly then all sorts of more interesting and lucrative and enjoyable opportunities will elude them, I think.

Rgds

Damon

about three weeks ago
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Slashdot Asks: Should Schooling Be Year-Round?

DamonHD Re:No, school should not be year-round. (421 comments)

Hi,

Apparently many of your <slightsnark>freedom-loving</slightsnark> countrymen *do* want it that way.

I mainly freelance, but I believe 2 weeks + about 2 weeks of public holidays is pretty much the EU minimum for permanent staff.

(I did fairly badly at school for a long time and then was ill; I don't think I'd have have been able to have had in the US the relatively good and 'entrepreneurial' life that I've had here in the UK. I'm just in the process of getting a new start-up into gear for example.)

Rgds

Damon

about three weeks ago
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Slashdot Asks: Should Schooling Be Year-Round?

DamonHD Re:No, school should not be year-round. (421 comments)

Um, in a reasonable employment environment that is a straw man.

In the UK it would be illegal to only give an employee a week off per year.

Rgds

Damon

about three weeks ago
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Slashdot Asks: Should Schooling Be Year-Round?

DamonHD Re:No, school should not be year-round. (421 comments)

I'm a primary school governor and I believe that the teachers at my school would much prefer a shorter summer break as the amount that gets forgotten each time, especially by pupils with marginal progress and attainment, is eye-watering. And that hurts them LOTS in later life. That does NOT necessarily mean more school days in the year, just differently distributed.

Also, more breaks spread out and less contention for the same block of a few weeks over summer would possibly make for cheaper and less stressful / crowded holidays.

(I also happen to believe that letting teenagers start the school day much later would be more humane and conducive to good results also.)

Rgds

Damon

about three weeks ago
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F-Secure: Xiaomi Smartphones Do Secretly Steal Your Data

DamonHD Re:So a non-denial denial (164 comments)

Well, actually, it does. Because Android to be useable requires Google account.

No.

I very deliberately did NOT set up a Google account on my Android Fairphone, and it does the basic things just fine, like, um, phone calls and even alarms. It even takes OK pictures.

I have EU citizens' contact details in my phone and I think that, given NSA revelations, I would be breaking the law to knowingly share/sync those details with/via a US entity such as Google (or Apple).

Would be nice to have local contact and calendar sync with my MacBook (OS X 10.9) but Apple made that hard, not the lack of apps on the phone so far as I can tell.

Rgds

Damon

about three weeks ago
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Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives

DamonHD Re:Nuclear is no good match for variable renewable (409 comments)

Only to a degree, and typically less following is possible as the fuel load gets older in each reactor.

Rgds

Damon

about three weeks ago
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Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives

DamonHD Re:And other costs (409 comments)

They already do from time to time in (eg) Germany and Spain.

Rgds

Damon

about three weeks ago
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Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives

DamonHD Re:And when you include end-of-life costs? (409 comments)

Wind and Solar do not work yet.

On which planet? They work just fine as long as you are not expecting unicorn farts. 15% of UK electricity roughly, ~50% of German.

And nukes are hardly perfect (though I have nothing against them and want at least some in the mix); ignoring the waste issue they don't load-follow well or at all (solar PV is a natural match for some/most load given that we're diurnal), and sometimes only manage twice the capacity factor of wind (eg look at some UK nuke fleet capacity factor vs offshore wind).

Rgds

Damon

about three weeks ago
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Brookings Study Calls Solar, Wind Power the Most Expensive Fossil Alternatives

DamonHD Re:Finally!! (409 comments)

Solar PV and reglazing (unless currently in a very poor state) should usually be low down the list of things to do if you are driven by maximising ROI (or ERO(E)I).

Rgds

Damon

PS. Having said that I have already done PV and triple-glazing though have not quite finished internal wall insulation works: see earth.org.uk

about three weeks ago

Submissions

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RIM co-CEO stomps off in huff

DamonHD DamonHD writes  |  more than 3 years ago

DamonHD writes "The BBC asks in an interview if "security" issues for example in the Middle East and India have now been resolved and Mike Lazaridis throws a hissy fit. It seems to me the question is fair, however uncomfortable."
Link to Original Source
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Reducing UK housing CO2 emissions by 80% by 2050

DamonHD DamonHD writes  |  more than 6 years ago

DamonHD writes "The Low-carbon Strategy from the Environmental Change Institute http://www.eci.ox.ac.uk/ at Oxford University identifies the policies needed to deliver an 80% cut in carbon emissions from UK homes by 2050. These cuts are achievable but will require a quantum leap in commitment from Government and a radical new approach.

The policies have been designed not only to dramatically reduce carbon emissions, but also to be delivered equitably. The poorest households will be prioritised for assistance and fuel poverty will be wiped out. The scientific consensus is that for the UK to play its part in helping the world avoid a rise of more than 2C, we must reduce our carbon emissions by 80 per cent by 2050. The household sector represents 27% of our total emissions and achieving deep cuts here is an imperative.

The low-carbon revolution starts at home.



Their previous work at http://www.40percent.org.uk/ from two years ago is also very interesting and thorough.

I'm amazed to find that with some simple measures at my home/office my family seems to have hit something like the 2014 targets already..."

Link to Original Source
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Dead Milk Tanker for Zero-Carbon London Home

DamonHD DamonHD writes  |  more than 6 years ago

DamonHD writes "Is it possible for a small urban (London, UK) home to be powered entirely by locally-collected Renewable Energy, both for electricity and for heating?

An important issue is that there is only ~20% of the solar energy per day in winter compared to summer, so one way to make the whole project more likely to work is to store energy from the summertime to the winter.

This article looks at storing enough heat energy out of the ~26GJ used by one house per year for water and space heating to last the winter, 'charged' by solar thermal panels year-round.

And yes somewhere between 1 and 3 dead water-filled milk tankers buried in the the ground could hold the required energy!"

Link to Original Source
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UK store chain giving away 1m CFLs on Saturday

DamonHD DamonHD writes  |  more than 6 years ago

DamonHD writes "Timed for when the clocks go back, Sainsbury's said it wanted to encourage people to save electricity during the dark months ahead.

To claim their bulb, customers will have to take an energy-saving pledge that urges people to recycle bags and switch to showers from baths.

Sainsbury's typically sells an average of one million green lightbulbs a year."

Link to Original Source
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DamonHD DamonHD writes  |  more than 7 years ago

DamonHD writes "Is hungover New-Year-Europe having an Internet outage to go along with the mandatory seasonal glitches in the banking networks ("I was standing in the pub and suddenly all my cards stopped working")?"

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