Apr 23

The UPSide state diagram

I think this diagram is now stable enough to put on the record.

UPSide state diagram

UPSide state diagram

Both this diagram and the Go code for the policy logic are generated from this pseudocode:


    render.state("DaemonUp", "Daemon running") 
    render.action("DaemonUp", "ChargeWait", CHARGING)
    render.state("ChargeWait", "Charge wait")
    render.action("ChargeWait", "MainsUp", CHARGED)
    render.action("ChargeWait", "OnBattery", MAINSDROP)
    render.state("MainsUp", "On mains power")
    render.action("DaemonUp", "OnBattery", MAINSOFF)
    render.state("OnBattery", "On battery power")
    render.action("MainsUp", "OnBattery", MAINSDROP)
    render.action("OnBattery", "Overtime", DWELLWARNING)
    render.state("Overtime", "User warned of shutdown")
    render.action("Overtime", "PreShutdown", DWELLTIMEOUT)
    render.state("PreShutdown", "Awaiting power drop")
    render.action("PreShutdown", "ChargeWait", RESTORED)
    render.state("UPSCrash", "UPS goes dark")
    render.state("HostDown", "Host has shut down")
    render.action("PreShutdown", "HostDown", HOSTDOWN)
    render.action("PreShutdown", "UPSCrash", BATTERYDRAIN, unreachable=True)
    render.action("OnBattery", "ChargeWait", RESTORED)
    render.action("Overtime", "ChargeWait", RESTORED)
    render.action("HostDown", "MainsUp", RESTORED_LATE)
    render.action("HostDown", "UPSCrash", BATTERYDRAIN, unreachable=True)

To see the full context of this, clone git@gitlab.com:esr/upside.git and explore the docs/ directory.

Apr 11

How many Einsteins per Africa?

In 2008, Neil Turok, an eminent phycisist, gave a talk about trying to find the next Einstein in in sub-Saharan Africa. I was thinking about this a few days ago after his initiative re-surfaced in a minor news story,and wondered “what are his odds?”

Coincidentally, this morning I stumbled across the key figure needed to upper-bound them while researching something else.

Continue reading

Apr 03

Fthagn to you too

I learned something fascinating today.

There is a spot in the South Pacific called the “Oceanic pole of inaccessibility” or alternatively “Point Nemo” at 48°52.6?S 123°23.6?W. It’s the point on the Earth’s ocean’s most distant from any land – 2,688 km (1,670 mi) from the Easter Islands, the Pitcairn Islands, and Antarctica.

There are two interesting things about this spot. One is that it’s used as a satellite graveyard. It’s conventional, when you can do a controlled de-orbit on your bird, to drop it at Point Nemo. Tioangong-1, the Chinese sat that just crashed uncontrolled into a different section of the South Pacific, was supposed to be dropped there. So were the unmanned ISS resupply ships. A total of more than 263 spacecraft were disposed of in this area between 1971 and 2016.

It’s just the place to dump toxic fuel remnants and radionuclides because, in addition to being as far as possible from humans, the ocean there is abyssal desert, surrounded by the South Pacific Gyre so it’s hard for nutrients to reach the place. Therefore there’s probably no local ecology to trash.

However…

According to the great author and visionary Howard Phillips Lovecraft, Point Nemo is the location of the sunken city of R’lyeh, where the Great Old One Cthulhu lies dreaming.

The conclusion is obvious. The world’s space programs are secretly run by a cabal of insane Cthulhu cultists who are dropping space junk on Cthulhu’s crib in an effort to wake him up. “When the stars are right”, hmmph.

EDIT: I was misled by an error in Wikipedia that claims Tiangong-1 was deliberately dropped there, and jumped to a conclusion. Now corrected.