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This is a reasonably simple process. Most of the process can be found in this Enigmail forum discussion.

1. Move the GnuPG keys to a USB drive. (For the purpose of this discussion, I will assume that the USB drive is X: and the directory on the drive is .gnupg.)
2. On the computer (not on the USB drive), change gpg.conf to include these directives:
   

   no-default-keyring
   keyring X:\.gnupg\pubring.gpg
   primary-keyring X:\.gnupg\pubring.gpg
   secret-keyring X:\.gnupg\secring.gpg
   trustdb-name X:\.gnupg\trustdb.gpg

   Under Mac OS X, assuming a volume name of USB drive, you would add:

   no-default-keyring
   keyring /Volumes/USB drive/.gnupg/pubring.gpg
   primary-keyring /Volumes/USB drive/.gnupg/pubring.gpg
   secret-keyring /Volumes/USB drive/.gnupg/secring.gpg
   trustdb-name /Volumes/USB drive/.gnupg/trustdb.gpg

   For Linux, it should be the same as for OS X but /Volumes/USB drive would be replaced by the mount point used for the drive.

3. And that's it.

If you want to use an encrypted partition or filestore, e.g. through TrueCrypt, the above instructions are still valid. However, you would point it to wherever you have TrueCrypt mount the encrypted partition or filestore.

I finally went through the process of setting up a PGP key. The fingerprint is:

9A86 1FA4 DADE 9C93 F2B0  7C23 38E9 ECDE D61A 0437

You can retrieve the key from a public keyserver or you can download it here.

(There is another PGP key with a fingerprint ending in FCD4 761B but I prefer that it is not used.)

The PGP key was created following the steps used by Ana Guerrero in her blog post.

To make use of PGP, I have set up pinepgp for PINE and Enigmail for Thunderbird. (I'm trying to move away from PINE because it's not working out particularly well but I still have a lot of mail and other such used in it.) I haven't set up PGP on my iBook yet but that's one of my projects for the next few days. I also want to move the PGP keys to a USB drive for security but I haven't started on that process yet either. I will include more information on both when I have them set up.

Any professionally taught programmer eventually has to learn binary trees. Some high school students are exposed early as part of the AP Computer Science AB exam but most have to learn it as part of a data structures course in college.

There are three ways to read a binary tree:

• Prefix: Root node, then left child, then right child
• Infix: Left child, then root node, then right child
• Postfix: Left child, then right child, then root node

Take, for example, this really simple binary tree:

The ways to read this are:

• Prefix: + 2 3
• Infix: 2 + 3
• Postfix: 2 3 +

The infix reading of this tree resembles (and, in fact, is) the standard way we write and interpret simple mathematical equations. "Two plus three equals..." (As an aside, all simple mathematical equations can be expressed as a binary tree. I'm not happy with the tools I have available to render trees right now so I will leave this as an exercise for you, the reader.)

The postfix reading should be familiar to anyone who owns a Hewlett-Packard graphing calculator. This form of representing mathematical equations is most commonly referred to as Reverse Polish notation. Postfix ordering of mathematical expressions is commonly used for rendering stack-based calculators, usually in assignments for a programming class.

The prefix reading resembles the standard way we use constructs in programming languages. If we had to represent "2 + 3" using a function, we would write something like plus( 2, 3 ). This is most clearly shown with LISP's construct ( + 2 3 ). Haskell's backtick operators around infix operators, e.g. `div`, have a side effect of reminding programmers that most functions are prefix-oriented.

So why discuss reading binary trees anyway? In a classroom, teaching the student how to read a binary tree leads to the student being able to program a way to read a binary tree which will then lead to other things. Here, I discuss reading them as background for the next post which may itself lead to other things.

Edit: (11 May 2009) Unfortunately, in the process of writing the next post, I realized that the entire premise of the post was invalid. So the next post will probably not have anything to do with trees.

Like many sysadmins, I have a lot of things going on. This is an excerpt of some of the current entries and an explanation.

• Look at planners.

  In Time Management for System Administrators, Thomas Limoncelli suggests getting some sort of personal assistant, either analog or digital. Since my current smartphone leaves a lot to be desired and I have an old-fashioned penchant for fountain pens, going the analog route seems ideal. So, to make an informed decision about what to get, I need to know what's available and that entails a trip to a local office store.

  I may use such a trip to look at furniture as well. I'm planning to work on an "office" in the spare bedroom to separate play from sleep. Having read about Mitch Haile's office, I am somewhat inspired. (Although proper furniture is expensive.) And, having just read this, a shredder may not be a bad idea either.

  The hard part about this is actually going out and doing it.

• Look at shelving.

  As mentioned above, I want to work on assembling a "home office." One thing I want to avoid is having the computers on the floor since it's not good for them and it's not really good for me. I've also damaged cables because of where the computers are and their proximity to the chair. (Not "major" cables fortunately.)

  I don't need expensive shelving, just durable shelving. "Nice" is a bonus. Plastic is out due to static concerns. Lowe's Home Improvement has several options, like this one.

  Like with the office store above, the hard part is actually going out and doing it. I could probably even do them both in the same trip since there's a Staples near the local Lowe's. (Although I prefer Office Depot out of our local office stores.)

• Install a personal wiki.

  At first, it sounds silly to install a wiki for use as what's little more than an online notepad. However, it seems like it would be a great way to write down things and flesh out ideas with little overhead. I could keep notes as documents on my laptop but that requires having access to the laptop. I'm fine with the requirement of needing to be online to modify it. I have a small Moleskine notebook in my coat pocket in case I need to make notes when I'm not near a computer. (I have also considered getting a portable voice recorder for taking notes as well.)

• Play with RT.

  In Time Management for System Administrators, Limoncelli suggests using RT as a tracking system. While this won't work for anything on the immediate to-do list, it would help make sure that nothing falls through the cracks.

  I already have RT set up (although I'm not sure the email functionality is working correctly, I'll have to check that) but I haven't done a lot of playing with it yet. I expect that I will end up rereading RT Essentials.

• Read the books I got this month.

  For some reason, February is usually a big book-buying month for me. Highlights include The Algorithm Design Manual, Code Complete, Programming Pearls, The Practice of System and Network Administration, and Pragmatic Thinking and Learning. This will probably keep me busy until, oh, May.

  There's other books I have which I'm sure I haven't read or don't remember reading. Most of them are still in boxes. I hope to unbox most of them when I'm done setting up the "office."

• Write a Rails app.

  I actually have a specific Rails app in mind. have mentioned before that I like books. However, I've taken to buying the print book + PDF bundles when I by from The Pragmatic Programmers. I've been saved some by having a PDF of the book when it has not been available.

  Since I can't have all of my print books while traveling but I can have all of my PDF books, I want to have an application I can use to search the PDFs for given content. (For various reasons, it should only be accessible locally from the laptop and only run when I want it to run. However, this isn't an application issue as much as a deployment one.) Ferret, paired with either pdftotext or pdftohtml, should work for the search component. It should be reasonably easy to write. I just, you know, have to do it.

The problem with practice is remembering to practice. This is especially true if you are trying to practice as a way to break a bad habit.

It's been a bad weekend for me. I forgot to practice touch-typing. And while I keep starting with tests for my Project Euler problems, I keep slipping to implementing large parts of the algorithm without further testing.

At least according to Thomas Limoncelli, "[P]sychologists tell us that it takes 21 days of doing a new behavior to develop it into a habit." Twenty-one days doesn't seem that long, does it? It's only three weeks, right?

Let's face it: It's hard.

It's not just three weeks of doing it. It's three weeks of making yourself do it. It's three weeks of making sure you don't miss a single day for whatever reason.

This is a common thing for people who decide to start exercise regimens. They start and keep going for a week and then stop. Something comes up and they put it off. And then they put it off again. And... I haven't found a statistic about the number of gym memberships that go unused but it apparently ranks as one of the top ten money drains.

It's easy to say that you need to force yourself to do things day after day, force yourself to think about doing them until you're doing them without thinking about them. It's easy to say this because talk is cheap. Action is not.