Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Re:I'll wait for a third party review... (Score 1) 428

"Traditional shingles set a very very low bar."

And yet they can work pretty well....
owner builder here, my house was shingled 30 years ago. They are in good shape for that age, but I need a new roof in the next five years.

I built the house with the correct slope for max solar gain (8 in 12 pitch, interesting to work on!). Still deciding between a roof installation and a ground array (26 acres, not many trees, so I have my choice of locations -- also no money, so not something happening immediately). I looked at the solar roof when it was announced, and again yesterday. Still no technical details on the website.

Meanwhile, I've been refreshing my memory on the measurements. I have a very basic roof: about 36' x 22' facing south, and the same facing north. (there is also a two car garage, but I'll ignore that for now). So 8 square (100 sq ft) south, 8 square north. 1600 square foot of roofing materials total. I was looking at what I thought were good quality shingles, about $110 per square. Shingles equal $1760. As a DIY job, probably $2000 total (nails, etc)

Alternately, I could go with a metal roof. No estimates on that yet. I suspect very similar price.

For a roof sloped like mine, I figure a 30 year life expectancy for shingles is a fair figure. Maybe even 40 if I buy ultra premium shingles. At any rate, past my life expectancy. So the replacement in 2050 is not my problem.

I'm waiting to get the rest of the story on the Tesla solar roof. But if Elon is right and I can get one for $2000, it is a strong candidate. (my suspicion is that it is more of a taxpayer $$ to Musk move, aren't solar panels unlimited in the 30% tax write-off you can get? So instead of $6000 for 5000 watts of panels, you pay $15,000 for 5000 watts of shingles and then the government gives you 3X the money back?)

PS - I ran the numbers for a north facing roof thru PVWatts, there seems to be about a 40% hit for having solar facing north. I don't know how that plays out, Tesla shingles that are cheaper without the solar, just so the roof matches? Or solar shingles so cheap that you don't even care.

Comment Re:good card for playing with GPGPU? (Score 1) 132

If you are interested in playing, any card 8xxx series or above works. (Nvidia) For instance, this Macbook has 9400M and I was able to download the CUDA stuff and run the sample programs with no trouble. RE the double precision and # of shaders (or performance), it really depends on what your code uses and how fast you need/want it. Easiest to get something running and then see where the bottleneck is, and how much it costs to fix.

Mostly my GPU usage is for folding (, I like the new boards because they run cooler. Just ordered a Gt240 for about $65 after rebate. An advantage is that the 240 doesn't need the extra power cable. I think it will fold proteins as fast as about ten Core2 2Ghz CPUs. The best card I have so far is a 250, it equals about 20 of those Core2's. Last summer I picked up some 9600gso cards for about $35, those have similar performance to the 240, but require the extra power plug.

I would like to do something like , but with much less $$. It looks like this new 480 is about 4X's the 295 performance for ~same cost. Sounds good to me.

PS - if you get some good GPGPU code running and need more performance, try to hook up with a .edu HPCC. Most of them are getting into CUDA and might have spare cycles. You might have to switch to linux.

Comment Wait & hope. Maybe 3650 wimax? (Score 1) 36

Knowledgeable people in the wireless ISP industry say whitespaces gear won't be available for at least another year. If it works out as expected, you would just buy it and use it, similar to today's wifi gear. It would require an Internet connection, to lookup the available channels database (daily) in your location.

As an alternative available today, you might consider the WISP 3650Mhz spectrum. The license for that costs $210. A brand I have looked at is Tranzeo, they sell Wimax gear in that frequency. (about $2000 for the AP, $250 for client radios). There are some exclusion zones that you aren't allowed to use 3650 within, so do a little research first.

And there is, of course, the usual wifi based gear. For example, see StarOS/Lucaya (my choice), or Mikrotik. And Motorola Canopy seems to work well at 900MHz.

Congratulations on being in the desert! You have a big advantage there with the lack of trees.

Slashdot Top Deals

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. -- Niels Bohr