Fixing the Emacs distnoted Problem on OS X 10.9

Posted on 2014-03-07 by jcs

With Emacs 24.3 (and possibly earlier versions) under OS X 10.9 there is a nasty problem that causes distnoted, the OS X distributed notifications daemon, to periodically suck up processor resources and basically tie up the machine. Sometimes it recovers on its own, sometimes you have to restart Emacs. That is particularly apt to happen after waking up from sleep mode.

The problem is fixed in the 24.4 release and I’ve been ignoring it while I waited for the new release. The other day, though, I ran out of patience and hunted up a patch I’d seen for it some time ago. If you build Emacs from source, it’s trivial to apply it: just follow the instructions in the patch commentary1.

After applying the patch and rebuilding, everything worked normally again and I haven’t had anymore runaway distnoted problems. Actually, the whole system seems snappier after I installed the patch. That’s not too surprising given that Emacs is always running on my machines. If you’re running Emacs on OS X 10.9, you may want to rebuild Emacs with the patch. As long as you have a C development environment, that’s easy. I don’t know if Homebrew and the other package systems have applied the patch or not.

Footnotes:

1

For some reason that I’ve long forgotten, I don’t have to do the 

make bootstrap

step. If you get a fatal error on the 

make install

step, just start over but omit the 

make bootstrap

step.

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HTML as an STD?

Posted on 2014-03-06 by jcs

The LA Times has a surprising revelation about Americans’ beliefs. You might find their views extreme but are they wrong? As far as HTML is concerned, maybe they’re on to something.

We geeks live in our own cocoon and sometimes forget that the everyday terms we use are mysterious—or, apparently, downright nasty—to the rest of the population. I tagged this entry as humor but maybe it really isn’t that funny. How can 10% of the population not know what HTML is? As I say, a cocoon.

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Dual_EC_DRBG Expalined

Posted on 2014-03-05 by jcs

Irreal readers are doubtless familiar with the broad outlines of the NSA’s insertion of a backdoor into the NIST Special Publication 800-90A elliptic curve random bit generator but may be unfamiliar about what was actually involved. Now Mother Jones has an excellent article about mathematician Edward Frenkel. The article is mostly about the beauty of Mathematics and how the teaching of it is terrible. I like that, of course, but the thing that will be interesting to most of you is a video interview with Numberphile in which Frenkel discusses the Dual_EC_DRBG algorithm.

He gives a simple and very accessible explanation of modular arithmetic, elliptic curves, how the Dual_EC_DRBG algorithm works, and how the NSA was able to insert the backdoor by the judicious choice of some parameters. It’s an amazing explanation because while Frenkel keeps the explanation well within the capabilities of a high school algebra student, he nevertheless gives a mathematically accurate description of what’s going on. If you have the slightest interest in the elliptic curve DRBG and the how it can be subverted, you’ll enjoy this video. It’s only about 11 minutes so you can enjoy it with your morning coffee.

Update: Frenkel talks further about the deplorable state of Mathematics education in this LA Times story.

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Why You Shouldn’t Trust the Government to Collect Information About You

Posted on 2014-03-04 by jcs

This is why you shouldn’t trust the government to build databases about their citizens. At the link, Charlie Stross talks about the growing scandal in the UK concerning the NHS medical records of every citizen in the United Kingdom.

Read Charlie’s post and see if you’d be comfortable with your government having this sort of information on you. Oh, wait. If you’re a UK citizen (and soon, a US citizen) they already do. The same, I’m sure, is true of most other developed nations. Remember, the scandal isn’t that there aren’t laws and regulations forbidding this sort of thing; there are. The scandal is they didn’t do a thing to stop it.

The NSA assures us that the private information they collect about us (wherever “us” happens to live) is closely guarded and safe. Except when it isn’t. What does it take to get people angry about this?

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Outage

Posted on 2014-03-03 by jcs

And, we’re back. Sorry for the outage. Apparently my hosting provider had a series of drive failures that overwhelmed their RAID system. One of the servers affected runs the database for Irreal. My provider is very proactive and has been working to resolve the problem since 4am on Sunday. If you’re looking for an inexpensive and reliable (current problems notwithstanding) hosting provider that can also handle your domain registration, be sure to give IXWebhosting a look.

Barring any further problems, Irreal should be back to business as normal.

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SBCL 1.1.16 Released

Posted on 2014-03-03 by jcs

The latest monthly release of Steel Bank Common Lisp is out. As usual, I had no problems building and installing the new release. You can download binaries or source at the usual place.

After last month’s major enhancement of the register allocator, this release was mostly bug fixes. You can see the exact changes in the NEWS file. One interesting thing about this release is that at least part of the process was performed in the air. Christophe Rhodes talks about that in this post about the release.

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A Sunday Treat

Posted on 2014-03-02 by jcs

This really tickled me:

Oddly, I was all set to click but I couldn’t find a link.

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Keys to the Internet

Posted on 2014-03-01 by jcs

The Guardian has an interesting story on the Seven People Who Hold the Keys to the Internet. Actually, there are 21 people but only 14 hold keys, the other seven hold code that can be used to recreate the key generation machine.

What’s going on here, really? The key in question is the private key to the DNS system that authenticates the database. If you’re like me, you think, “Well, what’s so difficult? You generate a random key pair and publish the public key while signing the database with the private key.” As usual, the problem is mostly political. How can we trust person X or country Y not to mess with DNS and route connections somewhere other than where the user intended. In view of Snowden’s revelations, these concerns seem less tin-foil-hat than they would have a year ago.

To make everyone feel more comfortable, the seven keyholders have access to smartcards that are used to generate a new master key every 3 months. The key holders come from multiple countries representing a cross section of the world. Read the article to see how complicated the protocol is to ensure that no one can corrupt the process.

I’ve spent most of my professional life dealing with computer communications and the Internet but I’ve never heard of this before. If you’re interested in how the Internet actually works or if you’re a James Bond fan, give this article a read. You won’t be disappointed. Also be sure the watch the video.

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Git Stash

Posted on 2014-02-28 by jcs

Over at softwarecave there’s a nice post on using git stash. In git, the stash is basically a stack on which you can push your current changes while you so something else. Maybe you want to change branches without committing your changes or perhaps you need to get rid of your current changes and work on something else in the current branch.

The post covers how to manipulate the stash. It turns out that it’s remarkably flexible. If you’re an Emacs/Magit user, the stash is usable from the magit-status buffer. If you’re a git user, and especially if you’re a Magit user, you should check this post out. It will make your life and work flow easier.

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Variable Pitch Mode

Posted on 2014-02-27 by jcs

Today I ran across a tweet that recommends the use of variable-pitch-mode when writing prose instead of code:

That mode gives you proportional fonts in the buffer, which, the tweet claims, is a big help when writing plain text.

It certainly looks nicer but I’m not sure that it helps all that much. The nice thing, though, is that it’s merely a display option and you can switch back and forth at will. Although the lines look a bit shorter because of the proportional fonts, Emacs is maintaining the proper fill column as you can see by switching back to normal display.

I vaguely remember using this in Aquamacs when I first started with Emacs because Aquamacs enabled it by default on text files. As I recall, I found it a bit distracting even then. The problem, for me, is that I don’t find the proportional font any easier to read and it’s not really WYSIWYG so there doesn’t seem to be a point. Of course, others disagree and find it helpful. Being Emacs, you can have it your way and even try it out at no cost. If you don’t like it, just turn it off and your buffer goes back to displaying normally. If you do like it, you can set a hook function to turn it on for text or Org or whatever. If you want more control, you can use the mode line.

If you haven’t seen this before, just call variable-pitch-mode to see what it looks like. Calling variable-pitch-mode again will turn it off.

Afterthought:

On the other hand, if you do turn on variable-pitch-mode, maybe the government won’t think you’re a cybercriminal like Manning, Snowden, and Assange.

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