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Comment 10^8th is a big number (Score 1) 432

The US was a rich country once. We aren't anymore. Making decisions like "no more reactors" got us here.

The basic deal here is that each U-235 atom that splits yield 170 MeV of energy; 1.7 x 10^8. The average chemical reaction yields a few eV. (Source: Los Alamos Primer, Robert Serber)

As a country we can't afford to throw away fuel which is that much more powerful. It's not only stupid, it's cruel.

For example, we have people working in coal mines because we won't build nuclear reactors. Coal mines are not very safe at all.

About 20% of our electricity now comes from 1st generation nuclear reactors. They're being run past their design life. We need to build more just to replace the old ones, and they need to be 1000 Megawatt size. We really should ask the French, because they have had a lot of success in this area.

People are talking about "conservation". They've been talking about that since the first Earth Day, which I remember. When you add a lot more people, you still need more electricity. Without electricity, we go back a hundred years as a civilization.

It's time to make the tough choices instead of letting them go to the next generation by taking no action.

    -- Dave

Comment Re:"Reverse Engineering" (Score 1) 298

Well of course the first thing that John Coster-Mullen would have to do is determine what microprocessor family was used on Little Boy. Is it an 8051, Z80, 68000, x386, PIC ? Generally even on OEM parts there's a basic part number. On DIP ROMS there has been a real effort to stay consistent.

John should bear in mind that the working timing of a nuclear bomb is 10 nanoseconds. This makes his microprocessor choices more limited; he'll need some speed here.

Then he needs to get to the code and examine it. If it's in a separate ROM chip this is much easier. For example, I was looking at a flashable EEPROM on a PCI card just yesterday evening and found it had a 29F001-TPC in a nice 32 pin DIP package. 128K x 8 bytes and nice little extras like auto-protection. It's a 120 ns part (from address setup to output enable* and the data pins settled.)

"Little Boy" was not a very efficient bomb at all. It was heavily overengineered. I can remember Ted Taylor calling it a "committee bomb" and a "stupid bomb" in McPhee's book. The committee wanted to make sure it went off and didn't just dig a hole, and hand the Japanese more than a hundred pounds of U-235. If I recall right, and this is just off the top of my head, it yielded only 12.5 kilotons or so.

Robert Serber's "Los Alamos Primer" is really useful here. It takes 10 nanoseconds (one "shake") for a fission to happen ("neutron multiplication time"). "The direct energy release per atom is 170 MeV".

"The energy release of TNT is ~~ 4 x 10^10 erg / gram, or ~~ 3.6 x 10^16 erg / ton.... Hence, 1 kg of U-235 completely fissioned yields about 20,000 tons of TNT equivalent, or ~~ 20 kilotons." [Serber is referring to tons as 2,000 lb tons.]

From this you can see that with a 12.5 kiloton yield, about two thirds of 1 kg of U-235 fissioned, so more or less, plus or minus, about a pound fissioned. Wikipedia says the bomb had 64 kg of uranium and only 600 mg. actually fissioned. I don't understand that number.

To which I can only say, see what happens when you use embedded Windows instead of Linux to drive your timing signals? I can just see it now. The bomb releases, starts falling, and in its microprocessor, it draws The Blue Screen Of Death and halts.

Thanks,

Dave Small

p.s. I really don't know why I wrote this. Maybe it was the coffee this morning.

Comment Been there, done that . . . (Score 1) 356

The high altitude nuclear shots the U.S. did to study the effects (and try for an effective ABM) did indeed kill some early commercial satellites.

This was most embarrassing, even if it was an "effect" to study.

There was an informal understanding between the Soviet and U.S. space program that no one would fire off a megaton at high altitude when there was a spacecraft and crew up there.

I wasn't around for most of the 1950's, but I believe we also managed to EMP Hawaii dark, or at least kill a whole bunch of fuses. But in the 1950's we didn't use much transistor technology; we were busy learning about it and developing it. (Please, I know that some transistorized machines came out in this era; I'm saying we didn't use them to control main power switches.)

Thanks,

Dave

Comment No, No, DO!!! (Score 1) 356

"Oh, please don't turn this into a zombie apocalypse survivalist fantasy! "

No! No! DO turn it into a Zombie Apocalypse Survivalist Fantasy!!! It'll be a heck of a lot more fun to read!

If I may put a vote in ... go find the movie "Fido". Easily the funniest Zombie movie I've ever seen. Stars Carrie-Ann Moss. Yep, that girl from the Matrix ... and she can actually smile! Set in 1950's America after a Zombie Apocalypse ... with a Zombie and a boy named Timmy ...

  -- David

This may look like a signature, but it's only yet another buffer overrun.

Comment Spin it up, THEN Shoot It (Score 1) 527

I've had very good luck with a couple 6 volt "lantern" batteries, a standard 4-pin disk drive power connector, and a few alligator clips. Connect the 6 V batteries + to -. On the "+" battery, connect its minus to the center two black "ground" leads. Connect the "+" of the "+" battery to the +5 line (red) going to the drive. Finally, connect the "+" of the other battery to the +12V (yellow) wire. So we're supplying ground, +6, and +12. Heck, it has a voltage regulator on +5 ... and it doesn't have long to live anyway.

Plug the drive in. Spin it up. IMPORTANT: Put it so the platters are at 90 degrees to you! In other words, put it so that if the platters explode, they won't hit you. You don't want it sitting on the ground with the platters parallel to the ground; you want them spinning at 90 degrees to the ground and to you.

Hike back a bit and shoot with a heavy slug. A slug from a 12 gauge works fine. All the rotational (angular) momentum is transferred to the frame as the platters stop almost instantly. The drive goes whirl-whirl-whirl, sometimes up in the air!

    I found that the .223 round from an M16A1 was strangely ineffective, but going to full auto made me feel better, and that's the point of all this. [ Yes it's legal to own an M16A1 here if you hop through the paperwork hoops]. Alas, the M16 was a toy I got rid of later ...

9 mm works very well at disassembling the drives, as does .45 cal.

  By the way, there are **absolutely terrific** magnets inside modern drives. Open 'em up and use a little acetone to unglue the magnets. They're the "supermagnets". And if you disassemble the drive with shooting, it is commonly opened FOR you!

          Shooting a disk drive that crashed and lost you a bunch of work is terrific stuff. In Las Vegas there are a couple places that let you bring in your computer or whatever and shoot it with automatic weapons. Hmmmm, maybe I should try an AK-47 someday, that's a .30 cal round...

      *grin*

David Small

Comment I think it's a good idea (Score 1) 275

Think big.

Take a million car batteries. Yup, lead acid. Why a million car batteries? Because they're so cheap -- we made a hundred million of them last year, and they're one of the best recycling stories out there). Don't be clever. New tech means R&D, and that means unexpected surprises.

Store them in buildings which are above 50 degrees F so that they last a very long time (and certainly not conditions under a hood). Some place near a large interconnect.

Use an inverter, or, just hook the batteries up with IGBT switches to "thermometer" up the voltage, and then back down, making AC.

I'm aware that this is limited storage; the batteries don't like to run at load capacity for long. But also note that Fairbanks has, I believe, 25 megawatts of battery backup.

I'll throw this into the "fresh meat" bowl here ...

  -- Dave Small

Books

Submission + - Terry Pratchett diagnosed with Alzheimers

dsmall writes: I did a -search- of this site and did not see anything on "Pratchett" so I thought I'd send this along.

The Turtle Moves!

Thanks, Dave Small

- — - — - — -

Author Terry Pratchett Has Alzheimer's
By RAPHAEL G. SATTER,AP
Posted: 2007-12-13 11:12:23
LONDON (Dec. 12) — Best-selling fantasy author Terry Pratchett has been diagnosed with a rare form of early onset Alzheimer's, he said in a message posted to his illustrator's Web site.

In a brief note to fans entitled "An Embuggerance," Pratchett, 59, said he was taking the news "fairly philosophically" and "possibly with a mild optimism."

Jorge Herrera, WireImage.com
Terry Pratchett, 59, has written dozens of books. Despite his Alzheimer's diagnosis, "I think there's time for at least a few more books yet," he said.

"I would have liked to keep this one quiet for a little while, but because of upcoming conventions and of course the need to keep my publishers informed, it seems to me unfair to withhold the news," he wrote on the Web site of Paul Kidby, who has illustrated many of his books.

Pratchett is best known for his Discworld series, which explores the residents of very flat, very weird and almost invariably hilarious planet dominated by the sprawling, chaotic city of Ankh-Morpork. Pratchett wrote his first Discworld novel, "The Color of Magic," in 1983, and 35 more books followed, many of which topped the best seller charts.

Pratchett's Web site said his novels have sold more than 45 million copies and have been translated into 33 languages worldwide.

His latest work, "Making Money," was published in September and Harper Children's was due publish a non-Discworld novel, "Nation," in 2008.

Pratchett said he would continue completing "Nation" and that he had already begun working on "Unseen Academicals" — another writing project.

"Frankly, I would prefer it if people kept things cheerful, because I think there's time for at least a few more books yet :o)" he wrote in his message. "I know it's a very human thing to say 'Is there anything I can do,' but in this case I would only entertain offers from very high-end experts in brain chemistry."

Copyright 2007 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without the prior written authority of The Associated Press. All active hyperlinks have been inserted by AOL.
2007-12-12 16:20:55
Software

Submission + - Excel 2007 Multiplies Oddly

dsmall writes: "Excel Thinks 65,535 = 100,000 Microsoft Working To Fix Spreadsheet Problems

POSTED: 12:42 pm EDT September 28, 2007

SEATTLE — Microsoft Corp.'s Excel 2007 spreadsheet program is going to have to relearn part of its multiplication table.

In a blog post, Microsoft employee David Gainer said that when computer users tried to get Excel 2007 to multiply some pairs of numbers and the result was 65,535, Excel would incorrectly display 100,000 as the answer.

Gainer said Excel makes mistakes multiplying 77.1 by 850, 10.2 by 6,425 and 20.4 by 3,212.5, but the program appears to be able to handle 16,383.75 times 4.

"Further testing showed a similar phenomenon with 65,536 as well," Gainer wrote Tuesday.

He said Excel was actually performing the calculations correctly, but when it comes time to show the answer on the screen, it messes up.

Gainer said the bug is limited to six numbers from 65,534.99999999995 to 65,535, and six numbers from 65,535.99999999995 to 65,536 and that Microsoft is working hard to fix the problem.

This short summary is Copyright 2007 by The Associated Press. All rights Reserved

==================================================================================



Here is the actual blog entry at http://blogs.msdn.com/excel/ :

Tuesday, September 25, 2007 6:51 PM Calculation Issue Update

Yesterday we were alerted to an issue in Excel 2007 (and Excel Services 2007) involving calculation of numbers around 65,535. The Excel team would like to provide a description of the issue and explain what we're doing about it.

Background Yesterday evening we were alerted to an issue in Excel 2007 (and Excel Services 2007) involving calculation of numbers around 65,535. The first example that we heard about was =77.1*850, but it became clear from our testing as well as additional reports that this was just one instance where Excel 2007 would return a value of 100,000 instead of 65,535. The majority of these additional reports were focused on multiplication (ex. =5.1*12850; =10.2*6425; =20.4*3212.5 ), but our testing showed that this really didn't have anything do to with multiplication — it manifested itself with many but not all calculations in Excel that should have resulted in 65,535 (=65535*1 and =16383.75*4 worked for instance). Further testing showed a similar phenomenon with 65,536 as well. This issue only exists in Excel 2007, not previous versions.

The Problem This issue was introduced when we were making changes to the Excel calculation logic in the Office 2007 time frame. Specifically, Excel incorrectly displays the result of a calculation in 12 very specific cases (outlined below). The key here is that the issue is actually not in the calculation itself (the result of the calculation stored in Excel's memory is correct), but only in the result that is shown in the sheet. Said another way, =850*77.1 will display an incorrect value, but if you then multiply the result by 2, you will get the correct answer (i.e. if A1 contains "=850*77.1", and A2 contains "=A1*2", A2 will return the correct answer of 131,070).

So what, specifically, are the values that cause this display problem? Of the 9.214*10^18 different floating point numbers (floating point on wikipedia) that Excel 2007 can store, there are 6 floating point numbers (using binary representation) between 65534.99999999995 and 65535, and 6 between 65535.99999999995 and 65536 that cause this problem. You can't actually enter these numbers into Excel directly (since Excel will round to 15 digits on entry), but any calculation returning one of those results will display this issue if the results of the calculation are displayed in a cell. All other calculation results are not affected.

The Solution We take calculation in Excel very seriously and we do everything we can in order to ensure that calculation is correct for all cases. We've come up with a fix for this issue and are in the final phases of a broad test pass in order to ensure that the fix works and doesn't introduce any additional issues — especially any other calculation issues. This fix then needs to make its way through our official build lab and onto a download site — which we expect to happen very soon. We'll add another post once that's taken place with a link to the download.

Posted by David Gainer | 159 Comments

=================================================================== Note (from Dave Small): In my testing with a small (non-Excel) calculator:

77.1 X 850 = 65535,
10.2 X 6,425 = 65535,
20.4 X 3,212.5 = 65535,
Of course, 65535 = $ FFFF = $1111 1111 1111 1111,
and, 65536 = $1 0000 = $0001 0000 0000 0000 0000
(I usually separate out the binary into hex digits for readability.)
The blog entry seems convinced that the problem is in floating point conversion. I find myself wondering if the programmers simply have a .Word 16-bit value and don't realize the significance of these numbers.
I do not have Excel 2007 and cannot test it, but it would certainly be interesting to check numbers around 32767 and 4 billion (e.g., a .Long full of 1's).
Thanks,

— Dave"
Linux Business

Submission + - thinkgeek sells toy: code for it, make money. (thinkgeek.com)

dsmall writes: "ThinkGeek's latest catalog has the Neuros (see them at http://www.thinkgeek.com/computing/drives/8af5/ )... The Neuros, a media device with a twist. It arrives without all the code to make it fully work. If you submit the code to make it work, you get paid.
From Neuros: "These bounties are a community style thing that is just a modest way to put a little money back into the Neuros community as a token for our appreciation. We hope and expect for people to collaborate, split bounties and credit and share information, etc. The deliverables and rules are sketchy and the interpretation is completely subject to the whim of the selection committee"
YouTube or Google video Browser Bounty: $1000
Flickr Photo Browser Bounty: $600
Implement a wireless remote using a WiFi PDA (or PSP) as the remote. Bounty: $500
TiVo style functionality for radio. Hook up the OSD to a FM/AM or Satellite receiver and do timed recordings or FF/RW and Pause Live Radio. Bounty: $700
Voip on the OSD. Plug a USB phone into the OSD and make calls without touching any of your PCs. Bounty: $500"
Might be interesting if you have too much time on your hands and are looking to make a quick Euro."

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