Sub Ubi

I spent a lot of time in the past few weeks reading about sub-prime mortgages. You see, I’ve just entered into a mortgage, and I wondered what my risk was. Was I in danger, in some way, because of all of this financial foolishness? Well, of course: everyone on the block around me could loose their shirt, and my home purchase would be devalued. I don’t think that’s going to be the case, however, so lets just say that my largest risk is probably general economic collapse.

But what if I were in a different situation? Say I had purchased a condo for around $200K. I purchased it with a short-term ARM (perhaps a 5-year) about four years ago, and I now need to decide what to do. The rate is about to jump, I don’t want to sell just yet, but at the same time, I don’t want to watch my monthly payments double in the next few years. Because I’m in a good financial position (right now), I decide to refinance. There are two ways I could do this.

It’s fine!

I used to live at 3 Woodland Way in Canterbury, England. In this house, we had a saying: “It’s fine!” Usually, this is said forcefully while something is on fire. Typically, that particular thing (whether it is a microwave or a coffee machine) should not be on fire. It was an assertion, not an assessment, intended to calm any housemates who may be witness to the unfolding disaster.

I could look around at my local economy, and declare “It’s fine!” I might, then, refinance with another 5-year ARM. Doing a bit of reading:

Under this model, an ARM that starts at 5.75 percent can increase to 7.75 percent in the second year, to 9.75 percent in the third year, and 11.75 in the fourth year. This means monthly payments will nearly double.

So, if I believe that my local economy will outshine the global economy, and that I will be able to refinance and sell within five years without substantial loss, then I should go ahead with the 5/1 ARM. Why? Because I pay less interest now, offload my property in three years, and save money in the process.

We’re screwed, Cap’n

I heard my housemate Ed say this more than once: this was often stated in aftermath of declaring “It’s fine!” The US economy is fcuked. We are in recession. We are getting hit hard on jobs, oil, and the ongoing debacle that is the subprime crisis. Hell, people have even stopped buying Hum-Vees.

No economy in the US will weather this well. I take that back: small, isolated micro-economies (rural towns, etc.) will continue to do as poorly as they ever have. In other words, they won’t be effected by large wiggles in the economy, because they run on a lower baseline and the ripples aren’t felt as fiercely. So, arguably, small economies will do better as the fecal matter hits the rotating blades.

Large economies (cities) cannot fare well. Cleveland is already being gutted (charts and graphs) by the subprime scandal, and we haven’t yet seen the fallout from this. To claim that any one market will do better than another is crazy-talk; certainly, I’d want data to support such crazy-talk, but… oops! That data comes from the future. So, I guess I won’t be seeing that data.

Snark aside, there would seem to be only one option: financial conservatism. The safest move is to refinance on a stable, 30-year mortgage. A 30-year fixed at 6.25% will involve a monthly payment of roughly $1200. This is a bit higher than the ARM, and yes, you pay $250K in interest over the life of the loan. However, the life-of-loan figure is a lie. We can refinance later if the rate comes down—not to buy a new car, but to jump from a 30-year to a 15-year mortgage, thus saving substantial cash. (We avoid the 15-year now because of the higher monthly payments; the 30-year gives us more breathing room right now.) Or, we can pay on a bi-weekly basis to cut the 30-year to a 22-year mortgage… if we’re making a steady flow of serious cash. (Remember the golden rule: the bank will always take your money.)

But again, if the goal isn’t to keep the property forever, it is simply a matter of “when” we are going to sell, not “if”. Hence, we shouldn’t care about the interest, or refinancing, or anything else for that matter. Instead, we should just care about getting into the safest financial position we can find now, and make sure that it is a position from which we can weather any coming crisis. If we manage to sell in three years, we paid a relatively small amount more (per month) for the safe 30-year loan over the unsafe 5/1 ARM. If the economy is in such dire straits in three years we cannot sell, and we’re lucky we’re employed and still have a place to live, then we want to make sure that our loan doesn’t yank that stability out from under our feet—which a 5/1 could easily do.

Keep in mind, I don’t actually know anything about long-term finance, but I am having a hard time finding ways to argue for the higher-risk strategy unless you’re prepared to loose. I, myself, would not be in a position to see base housing costs double.

Of course…

The safest-est move is to dump the property while/if there is a local economy that is in the mood to buy. Then, the whole discussion becomes moot, and the financial burden is covered by an SEP field… it becomes Somebody Else’s Problem.

If this were me, selling right now would mean I’d have to move in with my parents for a while, and it would be inconvenient… but I’d sleep better knowing that a clean, empty condo sells better than one with people in it. However, prepping a property for sale so that prospective buyers want to buy it as soon as they see it is another post entirely.

“To find things and play on it.”

Via robogeek.

http://www.youtube.com/watch?v=_RyodnisVvU

Awesome. A funky little rhythm bot.

Last semester, I introduced my students to structured data (including how to traverse self-referential structures), transitioned into classes and objects, and the basics of constructing GUIs in the object-oriented paradigm. A number of them mastered Model-View-Controller in this transition. This isn’t entirely remarkable—it’s actually a simple pattern, when the language itself doesn’t get in the way.

A Java program that produces this:

Comes from code that looks like this:

Of course, the output from the Scheme version looks the same:

But the difference is in the amount of code the student has to write:

What do I like about this?

• There’s less preamble (#lang scheme/gui vs multiple imports).
• The syntax is consistent with what has come before in the student’s experience.
• There aren’t any mystery calls (frame.pack()?).
• new is analogous to make-, which students have seen many times before.
• Callback functions follow naturally from previous work; event handlers are confusing.

I could probably make the list go on and on. At some point, I have to spend more time with JavaME, as it has a much simpler GUI model. And, given that the vast majority of the computers—those would be mobile phones—run JavaME (and not the full Java stack), it would be good to ask around and find out whether we’ll ever see a native version of BlueJ for programming against the ME classes.

Or, it could just be I prefer introducing students to simple languages, and then moving them on to more complex languages as necessary. But this is an old and tired rant, at best.

Tree sweater.

Not crazy. Not awesome. Crazyawesome.

I’ve switched almost entirely to mobile phones for communications; we haven’t had a landline all year, and don’t expect to this next year, either.

The most problematic thing about this would be the 2W dissipated by the phone’s cellular radio. That, and handsfree units are expensive—anywhere from $20 to $100 or more.

An expensive headset.

Then I remembered eBay! I was able to buy three handsfree cables for our phones as well as two for my father’s phone for less than the cost of a single Bluetooth headset. Granted, they’re cables as opposed to wireless cyborg implants, but frankly, I don’t care. At least the cable never needs to be recharged…

I will probably end up writing about this again.

Java textbooks are painful things.

I did a quick survey of a number of popular titles in the introductory Java textbook space. I considered the title “popular” if I had seen it on the shelves at SIGCSE on a consistent basis over the last several years. By-and-large, there are a lot of textbooks I consider crap, and I consider them crap for a variety of reasons. Sometimes it is because the writing is dry and unappealing to me (let alone a novice). Sometimes it is because the book does a horrific job of structuring/pacing material. Generally, I consider them all too expensive.

I threw together twelve books and ran some numbers on them:

The numbers to the right of each blob are the number of pages a student would have to read in order to get through the entire textbook in a 13-week semester. (I’m counting a week as lost to startup, and there is time lost to exams and the like as well.) The most expensive, and largest texts come in at over $120 and 1500 pages; this implies that students will read 120 pages per week while working exercises. Of course, no first-year computing student is going to read 120 pages of a mind-numbing textbook and do homework besides… not for just one of their four courses.

The smallest and cheapest text is not actually a CS textbook; at $10 and roughly 200 pages we have The Magus of Java, which has nothing to do with learning to program, but looks kinda neat. It is likely many introductory students would learn more from it than from the 1500-page beast at the other end of the spectrum…

The book in red is Objects First with Java. I’ve taught with it before, and as can be seen, it prices out well; it is expensive at $75 or so, but isn’t too large…. the student has less reading to do (per week) than many other books in that price range. That, and I’ve taught with the text more than once, and consider it to be a quality piece of work. In green is Java Programming for the Absolute Beginner, which has some reviews that make me think it would be a horrible choice for novices. The author would probably disagree, but the comments on that text set off warning bells.

I tend to agree with many of the philosophies of Allen Downey (whom I’ve had the pleasure of working with this past year) with respect to textbooks. He has published How To Think Like a Computer Scientist as a freely available text. What I particularly like is that he strives to keep each chapter short, so that a teacher can reasonably expect that students might read the material. It may be that I’ll have to write my own text this coming semester, focusing on basic mastery of syntax as well as concepts, utilizing both repetition (for mastery) as well as more open-ended problems (to encourage creativity and collaboration), all while keeping each chapter/learning unit as short as possible (for digestability).

We’ll see what happens; for now, this is just a long-winded rant-ish. But it is a problem/question/situation I need to deal with over the course of the next month.

I have to move stuffs from an apartment in Boston to (free, short-term) storage in Cleveland.

A U-Haul truck would cost me around $600 one-way from Boston to Cleveland. I’d get it for four days, which means I could conceivably do Boston-Cleveland-Meadville-Cleveland… if I hurry the whole way. The car would be towed behind. The cost of the rental would be approximately $700, and the fuel would probably cost between $250 and $300 (for Boston to Cleveland only). The total cost for a U-Haul-based move would be around $950.

If I go with something like ABF U-Pack, I can get a cute little 6′ x 7′ x 8′ box dropped off outside our apartment. I pack it full of our crap, and then they take it away. The cube gets dropped off at the same place I’d have to drive the U-Haul. The cost to ship a single cube from Boston to Cleveland is roughly $800. However, in-between, I don’t have to drive the truck; instead, Carrie and I would just hop in our little Echo and drive to Ohio. A U-Haul truck from Cleveland to Meadville and back would cost around $300 (rental plus milage), and fuel would cost around $100; so, the total cost for a U-Pack based move is $1200.

The final twist is that the real estate agency we worked with on purchasing our new home (yeah, that’s a subtle announcement) provides a truck that we can use for free. We could scoot out to Cleveland, pick up our stuffs, and drive back to Meadville, the only cost being fuel. Fuel would cost around $100. So, we could ship our stuff to Cleveland, and pick it up using the agency’s truck, and our total cost would be around $900.

In other words, I think I can avoid driving a truck across the country, and it comes out to roughly the same price. I like that idea a lot.

Update, later that day…

Pete D. points out that having free access to a moving truck only involved buying a house. So, to be fair, that truck cost a lot more than any of the other options…

I ordered a new computer today.

The fit-PC is a 500MHz computer with 256MB of RAM and 60GB of disk. It has two ethernet ports, a VGA port, audio in/out, and a serial port. It costs $325 (shipped), has Ubuntu 7.10 pre-installed (or optional Windows XP), and draws a maximum of 5W under load.

The fit-PC draws 5W under load.

To put that in perspective, my MacBook has a 65W power adapter. A typical desktop has a 200W power supply. The fit-PC draws less juice from the wall than an energy saving light bulb. It is fanless, so the computer is no louder than the hard drive… (which, in an aluminum case, is going to be very, very quiet). That, and it’s small. A CD jewel case is 142 mm × 125 mm × 10 mm. The fit-PC is 116mm x 120mm x 40mm. That means it is as tall as four CD cases, and has a footprint that is smaller than those CD cases.

This computer is slated to become the backup server for Untyped. I’ll plug in a USB hard drive (possibly two) and just let it back our dedicated host up. Once we get settled in our new home, I may find a use for another as either a firewall or as a media server. We’ll see… mostly, I’m just amazed to have found a fully-featured Linux computer that is so incredibly power efficient.

Links:

• Wikipedia
• Linux Devices
• ExtremeTech
• fit-PC website

I’ve had a marvelous year at Olin College. And this week, that year is coming to a close. Finals are over, and only EXPO and graduation remain.

Last week, my students threw at surprise going away party for me. By “surprise,” I mean “I had no idea it was coming.” By “my students,” I guess I mean “all the students at Olin I’ve interacted with in some significant way.” They came from Software Design in the fall, to HFID and Robotics in the spring, to SCOPE and independent research and projects… and even just a few who don’t fall into any particular category at all. For the time being, the blog’s header is a slightly larger version of our group photo:

This was a wonderful, wonderful surprise. They baked cakes (absolutely amazingly tasty), and all signed a huge card. The front of the card read “You’ve been an amazing teacher, mentor, and friend to all of us.” As teaching awards go, I think it counts as one of the best. I will say, however, that I had some incredible material to work with; every one of my students made my first year as a full-time faculty member an absolutely joy. These people were the reasons I wanted to go to work every day.

Thank you.

The Sony Ericsson Z750a gets horrible battery life.

Carrie and I just recently picked up two new phones on a family plan. The materials in the store said “up to 16 days standby” for the phone we chose. Now, I understand that it says “up to”, but this is gross.

I charged my new phone overnight, and then left it sit. Every now and then, I’ve used the phone’s internal battery meter to find out what its current charge status is. I dropped the data into Excel, and plotted it.

I know battery discharge isn’t strictly linear, but I don’t need to be a rocket scientist to see that the data has a linear trend so far, and that it is not anywhere near a 16-day standby life. Currently, if the battery continues to discharge at its current rate, I’m going to get between 3 and 4 days of standby time from my phone. Standby means I’m not actually using it. If I were to use the phone (to, say, talk to people) the battery life would drop rapidly.

The battery life on the Sony Ericsson Z750a is horrible, and is nowhere near the published values. Anyone choosing this phone because they believe it will get close to two weeks of standby time are sadly mistaken; this phone will eat through its battery in a huge hurry. It is a poor choice if you want your phone’s battery to last a long time. Consider that this is a brand new battery; after roughly 100 charge cycles, I can expect a degradation of around 5% (pdf). At 200-400 cycles, I might see my battery life degrade by as much as 50%. Now, if I have to re-charge my phone every two days under normal usage, that implies that I’ll hit 200 cycles in about 1 year.

And then I’ll have to buy a new battery.

This is not what I want from my phone. I want a phone with a long battery life that lets me make and receive telephone calls. I’m not interested in having to recharge it every few days, or even every night for that matter.