Category Archives: Mathematics

The Pension Crisis

It keeps getting worse.

As I’ve said in the past, if the federal government bails out a state, it should be under the conditions that it revert to territory status until it has demonstrated fiscal responsibility over a long period of time. And in the case of California, it should not be allowed to come back in as a single state. If this requires a constitutional amendment, I’ll bet you could slam one through enough of the more fiscally prudent states pretty quickly.

How Inevitable Is Trump?

Not as much as some want us to think.

[Late-morning update]

Kurt Schlichter has sympathy for the Donaldites.

So do I, but The Donald isn’t their (or anyone else’s) salvation.

Linux Problem

I’m trying to format a micro-SD to install Fedora on my Raspberry Pi 2. I’m following the instructions here.

But when I get to the part about building the swap partition, I’m getting an error message. This is the output of fdisk:

Command (m for help): p
Disk /dev/sdd: 29.7 GiB, 31914983424 bytes, 62333952 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0002ce31

Device Boot Start End Sectors Size Id Type
/dev/sdd1 2048 264191 262144 128M b W95 FAT32
/dev/sdd2 264192 1312767 1048576 512M 82 Linux swap / Solaris
/dev/sdd3 1312768 62333951 61021184 29.1G 83 Linux

Now here’s what happens when I run mkswap:

[root@new-host-5 raspberry]# mkswap /dev/sdd2
mkswap: error: swap area needs to be at least 40 KiB

I’ve tried searching for a similar issue, but am coming up empty. Anyone have any ideas?

[Update a while later]

OK, I’ve decided that it’s a bad SD. But now I’ve got a new problem; I can’t mount the W95 FAT32 boot partition:

Disk /dev/sdd: 14.5 GiB, 15560867840 bytes, 30392320 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device Boot Start End Sectors Size Id Type
/dev/sdd1 2048 264191 262144 128M b W95 FAT32
/dev/sdd2 264192 772095 507904 248M 82 Linux swap / Solaris
/dev/sdd3 772096 30392319 29620224 14.1G 83 Linux

Command (m for help): q

[root@new-host-5 raspberry]# mount -t fat32 /dev/sdd1 /tmp/rpi/boot/
mount: unknown filesystem type ‘fat32’
[root@new-host-5 raspberry]# mount -t auto /dev/sdd1 /tmp/rpi/boot/
mount: /dev/sdd1 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sdd1,
missing codepage or helper program, or other error

In some cases useful info is found in syslog – try
dmesg | tail or so.

It doesn’t work with “auto” or “vfat” either.

[Tuesday-morning update]

OK, not sure what the problem was, but after rebooting the machine, I managed to get it all to work. I haven’t actually tried booting the Pi, yet, though.

Gravitational Waves

This is a huge day for Kip Thorne (and others). Nadia Drake has a comprehensive story up already.

[Update a few minutes later]

Here’s another write up by Matthew Francis at The Atlantic.

[Update a few more minutes later]

Here‘s the paper itself.

[Update a while later]

And one from Miri Kramer.

[Update a while later]

And from Loren Grush.

George Washington’s Winters

What is the right climate?

Why are we defining ‘dangerous climate change’ with respect to the climate of the 18th century, which was the coldest period in the last millennia, with wicked winters? Why not use a reference point of 2000 or 1970? The IPCC doesn’t provide a convincing explanation for the overall warming between 1750 and 1950; according to climate models, human causes contributed only a very small amount to the global warming to during this period (so presumably this overall warming was caused by natural climate variability). Co-opting the period between 1750 and 1950 into the AGW argument muddies the scientific and the policy waters.

It would make much more sense — from a scientific perspective, from the perspective of adaptation and engineering, and in the public communication of climate change — to refer to warming relative to a more recent reference period. Since the emissions reference periods are between 1990 and 2005, this also adds to the argument of citing a more recent reference period for defining ‘dangerous’.

The argument that human caused warming is already ‘dangerous’ — widely made by politicians, the media and some scientists — flies in the face of scientific evidence reported by the IPCC AR5 and SREX. Extreme weather events were worse earlier in the 20th century, and sea level has been rising for millennia, with recent rates of sea level rise comparable to what was observed in the middle 20th century.

It’s almost as though there’s some sort of political agenda at work.