Monthly Archive for May, 2009

Oh-oh Baby, Got to Roll Me

This is awesome!

When someone complains that the pseudorandom number generator you’re using is not random enough, what do you do?  Well you could grab a copy of Knuth, or do a literature search on pseudorandom algorithms, or try to incorporate some external randomness from a keyboard or mouse or network events or maybe the Johnson noise from a big resistor.


You could build a giant banglevator (quick show of hands, who remembers Bing-Bang-Boing?) to roll actual dice for you.  Crazy, yes, but enough so that it Just. Might. Work. There’s video at that link!

Introducing the Dice-O-Matic mark II, now generating the dice rolls on It is a 7 foot tall, 104 pound, dice-eating monster, capable of generating 1.3 million rolls a day.

As a professional geek, this kind of overkill gets my juices flowing.  IYKWIM.

Hat tip to Bruce Schneier.

Chicks Love a Ride

Looka what happens when you leave your fresh set of wheels unattended in Kensington.  At least, if said wheels include a rack.   ‘Round midnight, and here’s this note on the windshield. Written on the back of a set of David Letterman timings.  What??  Only 7 and a half minutes of local avails?  Scandalous!

Interestingly, the rack is not currently set up to carry a bike.  Nor will it ever be, on account of this car is better suited for a spare-mount bike rack.  But maybe a ride of some sort is desired:  I hear it’s a big hill to get up to Kensington which, she would be tired.

Alas, ’twas a tease.  Next day I had to pedal my own self around the Mt. Airy test track, with super-biker squeaking about not being able to keep up.  Did I go too fast?  It’s always easier with a stiff frame, but oh the cost.  Maybe cheaper components.  Shifter?  I hardly know ‘er.

But it seems the days of beautiful exercise, fresh air, sunshine, helmet-head, pounding heart, burning quadriceps, raw throat, sweat-soaked clothing, near collapse from dehydration, and all that wonderful stuff draw nearer.  Huh.  Maybe I should just get a kayak.

Things I Hate, Part 4


But we showed them!  We walked out, drove to Carmax, and got almost the same car (one year older but half the mileage, and in a prettier color) for $1000 less, and were offered 50% more in trade, than we had after two hours of waiting at the dealer for “checking with my manager”, “calling another buyer”, “checking with my manager”, doing “anything we can to earn your business”, and my favorite, “Good news!!!  We reduced the price by an amount we hope your brain is too small to notice is about 1/3 of the amount we just said we could!!!11!!”

Also, having never traded a car in before, I was unaware of the trick where after they test drive your old vehicle, they fail to return the keys.  Nice.  Took 3 tries to get ’em back; once they appeared on the table I just grabbed them.

Carmax actually worked as advertised.  Car was as it appeared on the web, price was good (10% below Blue Book, and significantly better than the dealer), they were reasonably efficient at getting the paperwork done, and the only hard sell was for the extended warranty.  But even that was only two tries, and we moved on.  Plus the salesman sounded just like bounty hunter Jubal Early on episode 14 of Firefly! Carmax 1, Toyota of Glen Burnie 0.

Oh well, too bad for T of GB.  Of course they’re calling now, trying to get us back in with no doubt suddenly lower prices.  Do I take their call and tell them I bought one from someone else cause they suck, or do I let them keep trying for weeks?  Choices, choices.

ACS Alive and Well

Yee-hah! After 15 years in the space biz, finally something worked!  About time.  Kudos to the amazing team of people who made it happen, ending with Megan McArthur controlling the arm, Drew Feustel fetching the tools and parts from the storage bins, and John Grunsfeld pulling out the old and clicking in the new.

The Advanced Camera for Surveys is what took most of the really cool pictures you’ve seen from the Hubble Space Telescope in the last few years.  Then it broke.  The A side power supply for the CCD Electronics Boxes (CEBs) lost its 15V supply in the middle of 2006.  They switched to the backup (B) power supply and kept on running.  But then at the end of January 2007, the B side power suppy fried itself totally, in what must have been a very exciting flash if someone had been there to see it.  It was drawing close to a kilowatt for at least 10 seconds, and we’re basically talking a computer power supply here.  The pressure sensors inside HST registered some gas at the time, so something toasted itself but good.

Too close to the next mission to replace the whole ACS (the first one took 5 years or more to build), but a certain scientist/engineer named Dr. Ed Cheng thought we might could fix it.

Some background:  ACS comprises three cameras actually: Wide Field Channel (WFC), a 16 megapixel CCD camera with very low noise, which took most of the cool pictures; High Resolution Channel (HRC), a 4 megapixel CCD with smaller pixels, which was less used; and the Solar Blind Channel (SBC), even more specialized, and less used still.  SBC was still working, but the WFC and HRC electronics boxes ran off the same power supply, thus they were both no longer working.

So.  The plan:  Remove the circuit boards from the WFC CEB and install new ones which take their power from an external plug.  Then put in an external power supply and plug it in.  Brilliantly simple!  The new circuit boards connect to the CCD detector and the rest of ACS the same way the old ones did, through the original motherboard, which stays in.  Simply brilliant!

Continue reading ‘ACS Alive and Well’

Go Atlantis!

Servicing Mission 4 to the Hubble Space Telescope launches on Monday (if all goes well).  Weather looks good, and so far nothing schedule-killing has happened.  Almost there…

The final walkdown of the Hubble stuff was today.  No personal cameras allowed, due to they want to minimize the amount of stuff that might get dropped, so no photos until I get the official ones.  Just words.  And words cannot convey.  We drove out to the pad under the hot Florida sun, took off jewelry (again, falling things bad), left cell phones and key fobs in the car (unwanted radio emissions probably won’t set off any of the pyro activators, but probably isn’t good enough), taped watches so they can’t fall off, tethered eyeglasses, and went up to level 135 (that’s measured in feet) where the gowning room lives.

Continue reading ‘Go Atlantis!’