Notices by Rob Pike (robpike@hachyderm.io), page 2

That critically important web site you use once a year that requires you to reset your password every 6 months.

@mattblaze Let me edit that for you.

Internet: Be less happy.

Sign (ha) your newish building did not have the best tech installed.

Informative mail message of the day, as it appeared:

@woody Starlink itself is doing something bad, though: it's polluting the night sky with more lights than stars you can see with the naked eye. (And that's leaving aside the whole endless rocketry exhaust mess.)

We're wrecking the oceans, we're wrecking the land, we're wrecking the air, and so now with nothing else to wreck, we're wrecking the sky.

I just look up the definition of gcode. Wow. I mean, wow. Like, wow.

@timbray Research Unix's or Plan 9's astro can give it to you in seconds if you know the lat/long. Give it the -l flag for location, -d flag for date, and -c365 for a year's worth. Probably -k for local (kitchen) time.
Script away.

bismarck=% astro -kc3|grep 'The sun'
The sun sets at 20:02:28 AED
The sun rises at 06:15:17 AED
The sun sets at 20:01:42 AED
The sun rises at 06:16:17 AED
The sun sets at 20:00:53 AED
The sun rises at 06:17:17 AED

@detreville TOMATOES ARE A VEGETABLE

@adrianco @aka_pugs But my Mac Studio won't go to sleep without panicking, from the first day I brought it home. Time Machine backups have a nutty UI and don't back up the OS, only user files I believe. (Plan 9 had a much more integrated and complete way of doing this.) Encryption is barely an OS feature - it should be just an abstraction in the disk driver.

I don't think much has happened to the OS at all. I talked about that happening in 2000.

Arno Penzias, Nobel Prize winner (discoverer of big bang's residual radiation), my old boss and the reason my CV mentions a silver medal in archery, has died, aged 90. Although he did much more important things, for me his signature achievement was defending me not being fired from Bell Labs after Labscam.

https://www.youtube.com/watch?v=fxMKuv0A6z4
https://www.bell-labs.com/usr/dmr/www/labscam.html

This allows to make, say, a two-element lens with less chromatic aberration.

We make a too-strong convex (positive) lens using low-dispersion material, then a concave (negative) lens behind, of lesser power but higher dispersion. If you choose the two materials correctly, you can (partially) cancel out the spread of colors. The two different dispersions can be adjusted to compensate perfectly while allowing a positive optical power to remain.

Do the same with more lenses for better correction.

A fun detail is that Newton figured this out, but managed to use two materials of essentially the same dispersion, so his experiment failed and he gave up. But he had the right idea.

Fun watching the hacker news commentators try to understand how achromatic (and apochromatic) lenses work. I was utterly confused by this myself when I was a kid. Despite devouring Newton's Opticks I couldn't figure it out.

But it's pretty easy.

The refractive index (bending power) of optical materials varies with wavelength; this is called dispersion.

....

My day of woe continues.

I am trying to install graphviz on my mac, for probably the fifth time in history. I caved and tried to install MacPorts to enable this, as recommended at graphviz.org, but the installer for MacPorts itself is just hanging at the "Running package scripts" stage, for like 30 minutes, showing it to be perhaps as troublesome as homebrew, which corrupted my disk some years ago.

Is MacPorts doing some protracted thing, or is it just broken? Thanks.

Wow

/usr/bin/rsync -rtzvl --delete-after --include=/ports.tar --include=/ports.tar.rmd160 --exclude=* rsync://rsync.macports.org/macports/release/tarballs/ /opt/local/var/macports/sources/rsync.macports.org/macports/release/tarballs

Is it syncing the universe from across the world?

Well, if it is, it's not getting any data. Nothing on that pipe for many minutes now.

OMG it finished after nearly an hour. Really would have been friendly to have a "this will take quite a while" message.

Well, that turned out to be not worthwhile after all. I needed graphviz to get dot to make a blocking profile graph, from which I learned nothing at all. So it was back to logging after all. My old tools are still sharp after all.

Nonetheless, I do appreciate all the help people offered.

I learned today that babies' scalps secrete hexadecanal, which tends to lower aggression in both males and females. This might help explain why I find hexadecimal so soothing.

@timbray 2025 will knock your socks off, then, assuming we live that long.