Saturday, March 30, 2013

Brain replacement

When computational hardware needs replacement, there is some discretion as to how to re-instantiate software. If the new hardware is functionally equivalent, or can emulate the old hardware, a direct copy of a large fraction of software is appealing for its potential simplicity. If not, more forethought is necessary.

In my case I'm transferring between very similar hardware, an older MacBook and a newer MacBook. There is software to manage the copy (Migration Assistant), but Apple-think has decided that the ethernet cable is to be deprecated. Like the floppy drive (iMac 1998), 8P8C is archaic technology (MacBook Pro, 2012); not white, shiny or invisible. Radio-frequency EM communication is an option, but slow -- two days is too long to be without a brain to tinker with.

So a purpose built dongle was grudgingly desirable. $29 worth of grudge and desire. Even with a  copper wire channel I had time to watch the Oregon Duck's lose a basketball game during the copy operation. No brain required.

The hardware and GUI interfaces on the new and old are strikingly similar, particularly the operator defined elements. It's a bit disconcerting. Is this what it feels like to be a clone, the same in more ways than is comfortable for two bodies?

This feeling is amplified by shared remote memory. Evernote and Dropbox were seamless, but Google Drive failed in recognizing the copied directory ("This is not your original Google Drive folder."), and a renamed copy of the copy was needed, with proper incantations supplied by a Google search. It was a visceral reminder that all is not truly identical to what was.

In the recent past the many steps of getting a new machine up and running was manually reviewed, perhaps while swapping numbered floppy disks and cups of tea while waiting, forcing a reflection on the process. This brave new body hides more than it reveals. There is less need to know or reknow what is unique or unknown about a fresh brain.

There will always be glitches, rare interactions between an increasing number of software and hardware combinations. Bits of gnarl, comforting reminders that a clone is an imperfect copy of an imperfect copy.

Monday, March 25, 2013

Curiosity self-inspection

Function and reliability are primary design criteria for an expensive robot in a remote environment. Many of Curiosity's imaging systems are put to use looking at itself, not its target, Mars.

Curiosity is minimally autonomous, particularly with respect to self-inspection and troubleshooting. Robots of the future will need to include a detailed functional self-map, and the capability to compare the map with ground truth. Then they will need to decide what to do.

I'm surprised at how Curiosity's exterior design came out having a complex, art-deco look; many interacting parts means many failure modes. This photo is from a mast camera after waiting for a good sun angle.

    original image: 0224ML1058000000E1_DXXX.jpg

Monday, March 11, 2013

Julio Cortázar, axolotl

"I saw from very close up the face of an axolotl immobile next to the glass. No transition and no surprise, I saw my face against the glass, I saw it on the outside of the tank, I saw it on the other side of the glass. Then my face drew back and I understood."

[3/14/13 A relevant image I ran across here, Cortázar and camera and cat:]

Saturday, March 2, 2013

private robot spaceship launch

SpaceX CRS-2:
SpaceX CRS-2 is the fourth flight for SpaceX's uncrewed Dragon cargo spacecraft, the fifth and final flight for the company's two-stage Falcon 9 v1.0 launch vehicle, and the second SpaceX operational mission contracted to NASA under a Commercial Resupply Services contract.
The launch occurred on 1 March 2013. A minor technical issue on the Dragon module involving the thruster pods and solar panels occurred upon reaching orbit, but it was recoverable and solar panels were deployed after an hour delay.

The launch video is amazing. There is little action and only a few scene changes, but these are jaw-dropping: earth to space, first stage to second stage, orbital deployment.

Falcon 9 second stage just after ignition, illuminating the ejected first stage.

Falcon 9 second stage exhaust nozzle, glowing orange hot.

Falcon 9 second stage just after shutdown. "Vehicle is orbital."
Falcon 9:
Both stages of this two-stage-to-orbit vehicle use liquid oxygen (LOX) and rocket-grade kerosene (RP-1) propellants. The Falcon 9 can lift payloads of 13,150 kilograms (29,000 lb) to low Earth orbit, and 4,850 kilograms (10,700 lb) to geostationary transfer orbit, which places the Falcon 9 design in the medium-lift range of launch systems.

SpaceX uses multiply-redundant flight computers. Each Merlin engine is controlled by three voting computers (each composed of two physical processors constantly checking each-other) to instantiate  a fault-tolerant design. For flexibility, commercial off-the-shelf parts and system-wide "radiation-tolerant" design are used instead of rad-hardened parts. The software runs Linux and was written in C++.

If all goes well Dragon will dock with the International Space Station tomorrow, 3 March 2013:

Dragon ISS docking, grappled with Canadarm2 on 3 March, 2013

Dragon's unberthing, release and splashdown are planned for 25 March 2013. The Dragon will return 3,020 lb (1,370 kg) of cargo, 2,668 lb (1,210 kg) without packaging. Included is 210 lb (95 kg) of crew supplies, 1,455 lb (660 kg) of scientific experiments and experiment hardware, 884 lb (401 kg) of space station hardware, 84 lb (38 kg) of spacesuit equipment and other miscellaneous items.