James Cassell's Blog

Questions for Me

noreply@blogger.com (James Cassell) — Fri, 09 May 2008 13:14:00 +0000

These are questions I have been given to answer over the summer.

What do you want to do:
- In the Navy?
- In Life?
What do you want to get out of a M.S. in Computer and Systems Engineering?
What do you aspire to be next year in the NROTC program?
How can you balance the requirements of a M.S. and the NROTC program while maximizing the benefits of each?

Evolving Banner Blindness

noreply@blogger.com (James Cassell) — Mon, 31 Mar 2008 03:27:00 +0000

Banner blindness is a phenomenon where people grow to ignore ads on web pages. It started out as just ignoring flashy colorful banners. Recently, I noticed that I have developed a banner blindness to Google text ads. While this banner blindness can improve efficiency in browsing the web (if such a thing can be considered efficient), it can also lead to overlooking legitimate information.

The other day, I downloaded Sabayon Linux to see what it was all about. When I was running the live media, I was about to click "next" when I said to my self, "Hey! What's a Google ad doing in a live distribution options dialog?" I then realized that it wasn't a Google ad, it was simply a table of features and descriptions of those features.

There are two possible conclusions that I could draw. The first would be that I should never format information such that it could be mistaken for an advertisement. The secound could be that I should try to curb my banner blindness so as to not miss legitimate information formatted in this way. Perhaps, both conclusions are correct; they are not mutually exclusive, as far as I can see.

Fedora 9 Beta

noreply@blogger.com (James Cassell) — Wed, 26 Mar 2008 19:21:00 +0000

Yesterday, the beta of Fedora 9 was released. Overall, I am very impressed. The live CD, which actually fits onto a CD this time, booted with no problems on all of my systems. I was very pleased to see that they fixed a bug where one couldn't get 1920x1200 resolution. Everything works pretty seamlessly.

Having said that, it is obvious that this is a beta release. There are many bugs that need to be worked out, but the overall functionality is there.

One of the main problematic places for bugs is in SELinux policy. Many things that I try to do get blocked by SELinux, including updating the system. Of course, this will be worked out before the release, but it is an annoyance at the moment.

I am definitely excited for the upcoming release of Fedora 9, even though it is a whole month away. One thing that is interesting is that Microsoft will wait for 3 months after they have completed their code to release it to the general public, while that is half of a release cycle for Fedora.

Why Not Silverlight

noreply@blogger.com (James Cassell) — Mon, 24 Mar 2008 13:42:00 +0000

Recently, Microsoft has been pushing its relatively new Silverlight web technology. Microsoft is posing it as a competitor to Adobe's Flash technology. I don't like either of these technologies due to their proprietary nature. Flash has been around for quite a while, and is nearly ubiquitous. It has become so prevalent that it is very annoying to browse the Internet without it. I am not going to help Microsoft create the ubiquity of another such proprietary technology.

Microsoft is trying to push out Silverlight via Windows Update. On all the computers I keep updated, I have specifically opt-ed to not install this update. There is an open source implementation of Silverlight being written, but even if it is written to spec, Microsoft's will inevitably have bugs, and their implementation will become a de facto standard, similar to how the rendering engine of Internet Explorer 6 was, for a long time, the de facto standard of how web pages should be rendered.

The same holds true for Flash; there is an open-source implementation, but it does not work nearly as well as Adobe's implementation. This continues to be a point of annoyance as Linux distributions generally don't come with proprietary code on the install disc.

Churning Mind

noreply@blogger.com (James Cassell) — Tue, 18 Mar 2008 21:19:00 +0000

Last night, I went to bed at the decent hour of 2200 (10 P.M.) I was planning to almost get a full night's sleep, and to do my homework this morning instead of last night. Unfortunately, at around 0220 this morning, I was rudely awakened by the fire alarm. Apparently, someone had used the fire extinguisher, and there was smoke; I don't really know what happened. At any rate, we all had to go outside and wait for the fire department to get to the dorm and check it out.

This all lasted for probably 45 minutes or an hour. We were allowed back into the building. When I went back to bed, I couldn't immediately go back to sleep; my mind was flying in a million directions. I laid awake for nearly an hour before going back to sleep. At one point, I remember thinking of something that disengaged my mind, kind of like a clutch. I remember thinking, "well, that's interesting; now I can go to sleep." Shortly thereafter, I fell asleep. Sadly, I don't remember what it was that caused my mind to disengage, but it sure would be useful for times when I want to get to sleep in the future.

There have been a few times when I laid awake for the entire night. Needless to say, this is quite a waste, and if I could predict these times, I could use the time to do work. As Murphy's Law would predict, these difficulties of getting to sleep only plague me when I intend to go to sleep. At any other time, be it in class, watching a movie, riding in a vehicle, or almost anything else, if given the opportunity, I can go to sleep.

The Cost of Turing Tests

noreply@blogger.com (James Cassell) — Wed, 12 Mar 2008 02:23:00 +0000

The other day, I had the pleasure of visiting my aunt and uncle. When I was over there, I showed them my the website I had created for the National Honor Society at Mountain View High School, as well as my blog. We came upon the topic of Facebook. They were interested in what it was all about, so I logged in to my account, and showed them around.

One thing that arose was them wanting to click on things that would appear to other people as if I had done, and, for obvious reasons, this was undesirable. My uncle proposed that my aunt create an account, as it requires very little effort to do so. She entered the necessary information, but the page came back saying that she had typed the CAPTCHA incorrectly. At that point, she decided that she did not want to create a Facebook account -- for my aunt, the marginal benefit of having an account was less than the marginal cost of typing in the CAPTCHA.

The purpose of a CAPTCHA is to tell humans and computers apart. It is basically a Turing test. A Turing test is supposed to be a task that is trivial for a human to do, but nearly impossible for a computer to do. As it turns out, they are often onerous for humans to do, and computers have been able to do them in all cases with at least some success. In this case, Facebook lost a potential user due to the difficulty of their CAPTCHA.

Communications Cryptography and Key Signing

noreply@blogger.com (James Cassell) — Tue, 11 Mar 2008 03:04:00 +0000

I have recently become interested in the encryption and authentication of messages. Several months ago, I started reading up on PGP and its open source implementation GPG. Basically, this is a technology that allows only the intended recipient to read a message. It also allows for the authentication of the sender.

This authentication and encryption is accomplished via public-key cryptography. Basically, each person has two keys: one public and the other private. The public key is given to anyone for verification of a cryptographic signature, or to enable him to send the owner an encrypted message. The private key is used by its owner to sign outgoing messages, and to decrypt incoming messages; it is never disclosed.

The preceding is a very simplified explanation, but should provide a basic idea of what is going on. There does come a small problem: how can you know that the public key you have for a someone is really owned by that person? This is where key signing comes in. One solution to this problem is to meet in person and exchange keys, but it would be a pain to meet each and every person with whom you wanted to communicate. Therefore, when you meet in person and exchange keys, you also sign the key of the person you met to inform people who trust your key that these new keys actually belong to their apparent owners.

A web of trust is created by many people signing each other's keys. In general, the fewer hops in this web between your own key and and other key indicates how much you can trust the authenticity of that other key.

Anyway, I have not yet attended a key signing party. I was pleased to find out that the ACM at Rensselaer is going have such a key signing party on March 24, 2008. Hopefully there will be quite a few people there so as to greatly increase the size of this "web of trust."

Super Man-Like Hearing Abilities

noreply@blogger.com (James Cassell) — Mon, 10 Mar 2008 03:50:00 +0000

The other day, I noticed something interesting -- our brains have the ability to filter out noise interference. My ThinkPad speakers aren't very powerful. When I decided to listen to some music while riding in the car the other day, the speakers seemed pitifully mute. The noise of the car greatly overpowered the sound of the speakers.

I left the music on despite this, and about 20 minutes later, I realized that I could hear my music just fine; I hardly noticed the noise of the car. Two things are true here -- the car didn't get any quieter during the ride, and my music didn't get any louder. This indicates to me that my brain selectively filtered out the noise of the car, and allowed me to better hear the music coming from my ThinkPad.

Social Interactions with Friends and Family

noreply@blogger.com (James Cassell) — Sun, 09 Mar 2008 04:55:00 +0000

Today, I had the pleasure of visiting much of my family. I was able to visit my cousins, my aunts and uncles, as well as my grandparents. I stopped by each of their respective houses after being picked up from the airport. While I was able to see each of these people over Christmas vacation, I was not really able to have a decent conversation with them.

It seems to me that whenever there is a large gathering of people, no deep conversation happens. With many people, if such a conversation begins, it is inevitable that it will be interrupted. Thankfully, there weren't too many people today to have some good conversations. Now that I think of it, I hadn't had good conversations with my family for quite a while.

The same holds true in conversations with friends; if there is a large group, conversations between subsets of the group will inevitably be interrupted. The most vocal of the group seem to end up being those who direct the conversation. Actually, this semester, I have not even spent much time with friends; I always seem to have things to do. The other day, I did hang out with several friends; we had a ?smoothie movie night,? where we had smoothies (made of fruits and ice cream put into a blender), and we watched a movie. It was a rather enjoyable time.

Lack of a Normal Sleep Schedule

noreply@blogger.com (James Cassell) — Sat, 08 Mar 2008 04:45:00 +0000

This past week, I have pulled three all-nighters. I'm sure that this isn't healthy, but I get quite a bit of work done when I'm at the computing center. Most frequently, I seem to pull these all-nighters on Wednesday nights; Thursdays are my hardest days this semester. On Thursdays, I have class from 0600 (6 A.M.) until 1700 (5 P.M.) I really should get all of this work done on the weekends, but it never happens.

Hopefully, after Spring break, I can get into the habit of getting all of my work done on the weekends. I would then, theoretically, be able to get back to a normal sleep schedule. Since all of my things tend to be due at the end of the week, and since I have a history of procrastination following me around, I often find myself in a bad position with more work to do than can be done in an evening. I resort to pulling all-nighters that cause staying awake through my classes to be quite difficult.

I believe that this semester is so difficult for me because my typical week is unequally balanced; most of my work and classes are at the end of the week rather being evenly spaced throughout the week.

Cheating at Rensselaer

noreply@blogger.com (James Cassell) — Thu, 06 Mar 2008 21:41:00 +0000

This afternoon, I was taking a test on which I was faring poorly. I had studied for a couple of hours, but not as much as I should have. Actually, I will be happy if I pass the test. When I was taking the test, I happened to notice that the person sitting in front of me was cheating. This caused me to have a silent outrage; as I saw it, neither of us were ready for the test, but he got an unfair advantage. He had a piece of notebook paper that he was keeping discreetly hidden. I can only guess that this had formulas or other such information on it.

Such things as this have always outraged me. Either I have felt that it wasn't fair that I should have studied, and they didn't have to; or I hadn't, and neither had they, but they get the grade as if they had. This being college, the stakes for getting caught are much higher, but as I found out today, cheating still happens. I don't know why I had assumed that I wouldn't see cheating here at RPI, but for some reason, I did.

It makes me sad that such things happen here at Rensselaer. I do believe that these people eventually get what's coming to them. It is just frustrating now when it seems to be benefiting them so well.

[tagged for clean-up]

Beautiful Weather in Troy

noreply@blogger.com (James Cassell) — Thu, 06 Mar 2008 03:20:00 +0000

Troy, New York is significantly colder than my hometown of Stafford, Virginia. Recently, we had temperatures as cold as -19°C (-3°F), which, believe me, is very cold. I have, for the most part, gotten used to this cold weather. The past couple of days here, the temperatures have been above freezing. Everything is melting, and it is balmy outside. The other day, I went to my classes without my fleece, and had only my long-sleeved shirt.

I remember when my dad drove me up here in August, it was in the fifties (Fahrenheit), and we thought it was cold. I think it is interesting how one can become accustomed to a new climate.

On Tuesday, we (that is, ROTC,) even went for a nice run outside. It was actually raining today, which, while not ideal, was pretty nice compared to all the snow and sleet we had been having all winter. It seems that spring is finally coming along. I am, however, not looking forward to temperatures over 60°F. My dorm does not have air conditioning, and this provides for a very uncomfortable atmosphere. I remember all too well from the beginning of last semester what that was like.

(I have not been proofreading my posts lately, so they are of lesser quality. I will correct this over spring break, which starts in a very few days.)

My Printer: Brother HL-5250DN

noreply@blogger.com (James Cassell) — Tue, 04 Mar 2008 22:28:00 +0000

When I came to school last semester, I brought my dad's old printer with me. It initially had the problem of black lines through whatever was printed. I fixed this by buying a new toner cartridge for it. About half way through last semester, it died. It was giving me a "50 Service" error. I found that this could be fixed with a $70 replacement piece. I was reluctant to spend so much money on such an old printer.

Last week, I had had enough with using the school printers, which both cost money to use, and didn't print as well as could be desired. I started looking at printers over at my favorite on-line retailer, NewEgg. I decided to go with the Brother HL-5250DN. It is a network laser printer, the only kind I would consider buying, and it has a built-in duplexer (that is, it can print on both sides of the page). It prints at 1200x1200 DPI, which is very sharp. (The LaserJet II that I had only printed at 300x300 DPI.)

Currently, I have the printer set up so that it is on it's own isolated network (which is just it and a wireless router). I connect to the wireless router whenever I want to print. To set it up properly (i.e., so that I could print to it from anywhere on campus), I would have to have to obtain some more networking hardware. Currently, my five-port switch is full and I don't have the desire to spend money on more networking hardware.

The printouts from the printer are very clean, and it is pretty quiet. The only negative thing about the printer is that whenever it gets ready to print, it draws a large amount of current, causing the lights in the room to flicker. Other than that I am very happy with this printer. The replacement toner costs around $75 or so, but I won't need that for a while.

Parallels Between Blogging and Programming

noreply@blogger.com (James Cassell) — Tue, 04 Mar 2008 01:19:00 +0000

I have been programming quite a bit lately; my Computer Science 2 class assigns an involved programming problem each week. These take several hours each. When I work on my project, I go about writing my code, and as soon as I need to reference some other piece of code, I will change gears and write at least the interface for it (i.e., the prototype). I will later go back and write the implementation of the function or class that I prototyped previously.

I find that much of the same happens when I am blogging. As I am writing, I think of other posts of mine that I would like to reference (i.e., link to). Many times, I find that I have never written such a post. While I haven't been able to link to non-existent posts, I have written down notes for myself to go back and write such posts in the future. My "about" page is one post that I made so that I would have it for future reference. My post about my Alienware notebook is one that I had tried to reference on many occasions, only to find that it didn't exist. Yesterday, I finally got around to writing the proverbial "implementation" of that which I had tried on many occasions to reference.

In writing code, there are many ways to achieve the same results, but have the code look very different. One can write two statements that are logically identical but are syntactically different. It is the same with the creative use of language; I can divide my thoughts with a semicolon, a period, or in less formal writing, (such as a blog,) with an em-dash. There are, of course, many other ways to vary the used syntax, but retain the same meaning. If one does not master this variation in the use of syntax, his writings end up being quite dull and boring, much like the first several years worth of posts on this blog.

Just as I am happy to continue learning programming syntaxes and constructs, I am interested in learning and practicing proper grammar in all areas of communication. This is the one area of "humanities" that I have ever enjoyed; I have never liked the critical analysis of literature or other such things.

Alienware Notebook

noreply@blogger.com (James Cassell) — Mon, 03 Mar 2008 03:33:00 +0000

It is extremely late to be writing this post, but, I have tried to reference it on a few occasions only to find that it didn't exist. In August of 2006, I made my first major purchase (read: over $1000.) I had amassed a non-trivial amount of savings, a large portion of which I wanted to spend on a laptop computer.

Planning

After looking at some of the available options, I had formed several requirements. First, the new computer had to have a high-resolution screen, preferably 1920x1200. Second, it had to be more powerful than my existing system, which was an AMD-based desktop (that I still have and use today.) My third requirement was formed later in the game -- I wanted my keyboard to have a full numeric keypad. These requirements ruled out most of my options. Initially, I wanted to buy a bare-bones notebook which I could build myself, but there weren't many of these, and none of them met my requirements.

Purchase

The numeric keypad requirement limited me to 17-inch models. The hardest requirement to fulfill was that of the high-resolution display. The only notebooks that seemed to have this were Alienware's. I priced out an Alienware, and found that they charged way too much to upgrade the processor or memory compared to how much it would cost to do so myself. I priced out and purchased a system with the upgrades in place that I wouldn't be able to perform myself; the system came out to just over $2000. The two major limitations of this configuration were the processor and memory. The system I bought had the bare minimum in terms of memory: two 256-MB sticks for a total of 512 MB. My processor was the Core Duo, T2300 clocked at 1.66 GHz. Ironically, three days after my system shipped, four days before I received it, Alienware started selling my system with the Core 2 Duo chips. The most obvious advantage of the Core 2 over the Core is its 64-bit capability. Needless to say, I wished I had waited several days before ordering.

Performance and Upgrades

I got the machine with Windows XP Media Center Edition, but, shortly after receiving it, I over-wrote XP with the release candidate of Windows Vista. Having only 512 MB of memory meant that Vista didn't run too well. I did make use of the new ReadyBoost, which made a noticeable albeit minimal improvement in responsiveness. About two months after buying the system, I got around to upgrading the memory to 2 GB. The system ran much more smoothly after that.

The machine played machines decently well; it could play Half-Life 2 at full resolution at a very playable frame rate. The video card in the system was the high-end ATI Mobility Radeon X1800. I actually didn't play too many games on it due to school and other things occupying my time, though it did play them well when given the chance.

In June of 2007, I again upgraded the memory, this time to 4 GB. Some of this was wasted potential as Vista only recognized about 3.5 GB. I upgraded my mom's newish laptop with the old 2 GB from my system as I had no other use for it. In July, I did another upgrade; I upgraded my processor to the Core 2 Duo T7200 clocked at 2.0 GHz. Again, I upgraded my mom's laptop with the older processor, bringing her to a dual core from a single core system. This left my hard drive as the least capable piece of hardware in my system; it only held 60 GB of data, and was only a 5400 RPM drive. I never got around to upgrading this part of the system.

Current Status

This leaves my system specifications as follows:

Alienware Area 51 m5750
WUXGA (1920x1200) TFT "Clearview" 17" display
Intel Core 2 Duo T7200
4GB DDR2 667MHz RAM
ATI Mobility Radeon X1800 (256MB) Graphics Card
60 GB 5400 RPM Hard Drive

This system currently serves as my secondary system, and is my Windows machine. My Rensselaer-issued Laptop currently serves as my main machine and runs Fedora 8. My two servers run Windows Vista and Fedora 8, each serving its purpose. Perhaps this summer, I will have time to play Half-Life 2: Episode 2 and Portal to make use of this once cutting-edge, but now aging technology. In total, I have spent a little over $2600 on my Alienware, including the initial system and subsequent upgrades.

Friends at Rensselaer

noreply@blogger.com (James Cassell) — Sat, 01 Mar 2008 19:01:00 +0000

So, I'm finally getting around to writing this post. No one bothered to comment on my Proposed Topics for Discussion, but a couple of people told me personally that this one would interest them. Anyway, I'll get on with it.

Room Mate

So, first, we have my room mate -- he is the first person I met here at RPI. We are both in ROTC, we both go to RPI, and we both have slightly similar opinions on political issues, but the similarities pretty much end there. His being a good room mate in combination with my being able to get along with anyone who is not trying to not get along with me makes for a decent combination. (I suspect that I probably get on his nerves at times, but he usually doesn't mention anything.)

ROTC Friends

The several days of a hell-like experience that we fourth-class midshipmen went through together created an environment where, for the most part, we are all comfortable with each other. When I go to the dining hall, there is a high chance that someone who is in ROTC will be there. If I don't see someone else with whom I wish to sit, I can always sit with one of these people. Of course, I am closer to some more than others, but from what I can tell, any community turns out this way.

"Silver Bay" Friends

My best friends here at RPI are those whom I met on the student orientation overnight trip, or through people I met on that trip. It still holds that that trip was the most fun that I have had since coming to college. Some of the people I met there, I hardly ever see, but the few whom I do still see regularly are my best friends here.

This semester, I haven't really done anything fun with my friends; the highlight of many of my days turns out to be mealtimes spent with friends. I always have a lot of work to do (thanks, partially, to my legacy of procrastination that still follows me.)

(I was entirely lucid when I wrote this post, unlike my previous two posts.)

57th Joint Service Military Ball

noreply@blogger.com (James Cassell) — Sat, 01 Mar 2008 04:59:00 +0000

Being in Naval ROTC, I had a mandatory ball that I attended this evening. The best way to describe my experience was awkward -- for a contiguous four hours. I didn't really have enough acquaintances where I could be talking to someone the whole time, nor did I have anyone I could leach onto without making the situation worse.

There were lots of important (relatively) high-ranking people there. I didn't really care to talk to these people any more than I cared to be there. Thankfully, the captain didn't stay too long after the ceremony was concluded. (We could not leave until the captain left.) The three (including me) people in the car I was riding in did not have dates, so all of us were eager to get out of there as soon as possible.

Sadly, the time that I spent at the ball would have been better spent doing a computer science project that is due at midnight (but on which I now have to waste my final late day.) The seven hours or so I would have had to do it would have been sufficient to get it done.

(I will clean up this post at the same time as I clean up the previous; the same conditions are true as then.)

Best Tool for the Job

noreply@blogger.com (James Cassell) — Thu, 28 Feb 2008 22:15:00 +0000

I have recently become quite interested in open source software. As a matter of fact, I have made it to a point where I prefer, for example, Linux (in my case, Fedora,) over Microsoft's Windows. Given two functionaly equivalent pieces of software, one open source and the other closed, the clear choice is the open source option. Having said that, I will choose the best tool for the job regardless of whether or not it is open source.

One example of my choosing the best tool for the job is my choice to use Opera as my web browser. I like opera because it is a lightweight browser with a rich feature set. It has an integrated feed reader, mail client, chat client, as well as many other useful features.

More recently, I switched to using Sun's Java virtual machine as an alternative to the using the fully open source version that came bundled with Fedora. I am guessing that the open-source virtual machine has some unknown incompatibility with my hardware; Eclipse, my java-based development environment, had many stability problems until I switched virtual machines. I had been blaming the extremely poor performance on Eclipse and the fact that it was written in Java when, in fact, the problem was a faulty implementation the virtual machine. (This problem actually gave me a large amount of grief; my Google searches turned up no one else with the same problem, which is quite unusual for any computer-related problem.)

Another proprietary program that I decided to use instead of the open-source alternative is NX, a remote desktop solution that works on both Linux and Windows. I initialy tried the open-source version of it, but that gave much grief.

There are also a great many open source tools that happen to be the best tool for their respective jobs. Examples of these include Linux itself; Eclipse, my IDE; Pidgin, my instant message application; as well as a great host of other open source software solutions.

One tool that happens to be the best for its job is µTorrent. This is the absolute best Bit Torrent client available. Unfortunately, it is only available on Windows. This has been my stated reason for still having Windows Vista on my Alienware notebook. I have read that µTorrent can be run on Linux through WINE, but have had neither the time, nor the modivation to try it to this point.

Linus Torvalds, the mastermind behind Linux, also happens to hold this viewpoint. At one time, it came back to bite him. He had been using a proprietary solution for keeping track of the Linux kernel source code, but the company decided to not renew the free license that had been granted. Linus's solution to this problem was to write a new best tool for the job: git. Git is now the fastest, and arguably, the best tool for keeping track of source code. Linus was fortunate enough in being a genius that he could simply write the best tool for the job when the old one was no longer available to him.

(At this point, I'm just rambling as I'm very tired; I'll clean this up later.)

Correlation Between Font Size and Screen Brightness

noreply@blogger.com (James Cassell) — Thu, 28 Feb 2008 00:45:00 +0000

Over the course of the day, I began to realize that there exists a strong inverse relationship between the size of the font on the screen and the light required to comfortably read it. I noticed that when I am in class, I have my laptop screen on the dimmest setting so as to allow my battery to last longer. At this low brightness setting, in a bright classroom, I blow up whatever I am looking at to nearly double its native size to be able to read it comfortably.

At the other end of the spectrum, I significantly decreased the font size in Eclipse, my programming environment, so that I could see more of my code at once. After doing this, the first thing that I did was turn up the brightness on my screen, which allowed me to see my code much more easily.

I am sure that this trend has its limits in either direction; if you get too dark, you won't be able to see the text, no matter how large you make it. Since the human eye only has a certain level of precision, if you make the text too small, increasing the brightness will not do enough to make the text readable. I am fortunate to have good enough eye-sight for this observation to hold for a relatively large range of brightness levels.

Qualifying Statements

noreply@blogger.com (James Cassell) — Wed, 27 Feb 2008 04:16:00 +0000

The art of qualifying statements is something that nearly every politician has mastered. I have used it myself, notably in my Thoughts on Harry Potter before reading Book 7. Nothing I said in that post turned out to be incorrect. I referenced things such as "the apparent [emphasis added] murder of Albus Dumbledore," and argued that Snape was "not as [emphasis added] evil as it would seem."

In the first case, my "apparent" qualifier was warranted; it is revealed in The Deathly Hallows that "murder" is a bad characterization of what happened. In the second case, it turns out that my qualifier was not needed at all, and my proposition was completely correct.

I was having a conversation with my friend the other day, and he asked me a question about where technology was going. My response was so well qualified that, if examined closely, it conveyed no information at all; at most, it may have conveyed an opinion, but nothing more. I find it interesting how anything can be said truthfully as long as it is properly qualified.

Rodney McKay

noreply@blogger.com (James Cassell) — Mon, 25 Feb 2008 22:24:00 +0000

When I was watching Stargate Atlantis the other week, I realized that I was very much like the character Rodney McKay with the major exception that I know how to keep my mouth shut. The episode I was watching when I realized this was "Trio." McKay believes himself to be able to do anything and thinks very highly of himself. He also has a bit of trouble relating with other people.

McKay and Dr. Keller are quickly becoming my favorite characters on the show. As a matter of fact, one of my favorite quotes comes from a dialog between the two:

Keller: McKay! I've been trying to reach you.
McKay: Well, you know, trying to save the city and what not.
[several minutes later]
McKay: You're a genius.
Keller: Well, you know, trying to save a life and what not.

Hard Drive Encryption Vulnerability

noreply@blogger.com (James Cassell) — Mon, 25 Feb 2008 04:51:00 +0000

Within the past few days, a vulnerability in the implementation of hard drive encryption was publicized. The problem applies to just about all hard drive encryption schemes -- Windows and Linux alike.

The Problem

The root of the problem is the same as the problem with DRM; the computer must hold the decryption key in order to be able to make use of the encrypted resource. This has been implemented by storing the key in RAM, which, common knowledge tells us, loses its contents when power is lost. This common knowledge assumption has a caveat that is not common knowledge; this loss of memory is not instantaneous. The memory may hold its contents for minutes after it loses its power. If the RAM is chilled before having its power cut, it will hold its contents for hours.

There are several ways that this can be exploited. If someone steps away from their laptop for a moment, an attacker could cut the power, connect an external device from which to boot, and their device could copy the contents of the memory onto itself. Somewhere in this copy of the memory would be the encryption key, which can be used to read the contents of the drive.

A Possible Solution

The article I referenced says that "There seems to be no easy fix for these problems." The hardest part of that assertion to contradict is the "easy" qualifier. However, upon reading about this problem, a seemingly obvious solution came to me. Modern processors have plenty of registers as well as on-board cache. Why not reserve one or more of these registers to hold an encryption key? If using a register would be too expensive, surely it would not be too expensive to use some of the plenteous cache that modern processors possess.

Upon considering this, I realized that people may very well want to have more than one encryption key. A possible solution for this is to store a key (say, a 256-bit key) that is randomly generated each time the system is booted. It could be stored in the manner I described above. This key could then be used to encrypt any other encryption keys before they are stored in RAM, and to decrypt them anytime they are retrieved. The only thing that needs to be done is to ensure that this randomly-generated key does not ever find itself in RAM.

A Word of Caution

Before writing this, I searched through the several hundred comments on the article, and found that several other people had mentioned the processor cache, asking if it were vulnerable. This indicates to me that this solution is, to some extent, common sense. It would be necessary to have security experts examine this approach before anyone tried to implement it, so as to avoid another disaster similar to what happened with the fatal weaknesses of WEP.

Great Sadness over a Trivial Concern

noreply@blogger.com (James Cassell) — Sat, 23 Feb 2008 20:48:00 +0000

As the title may have indicated, I am very sad right now. I woke up this afternoon (as I do on most Saturday afternoons after catching up on sleep). I saw on my phone that I had missed several calls because it was on silent and I didn't hear it. I saw that both of my parents had called me several times, and that there were several messages. It turns out that, today, my father and sister were visiting the Military Academy at West Point, which is less than a hundred miles from here. They had been trying to get a hold of my because they were going to stop by and visit briefly.

By the time I got their messages, they were already on their way home, having not been able to reach me. I called my dad, and my sister answered and told me as much (that they were on their way home.) My verbal response was, "oh, well," as is my response in any situation where a loss on my part can in any way be considered my fault. I must say that this displeased me greatly. I realize that, in the long run, this annoyance has very little meaning. Despite this, I am very sad.

I decided to go get some food where I believe that at least two people wished they hadn't said, "how's it going?" in passing. They had to listen to my recount of why today is a bad day.

To make matters worse, today would have been an ideal day for them to have visited as there are "Winterfest" activities going on all weekend on campus. I must say that I haven't been this sad since shortly after leaving NYLF/tech. It seems to me that I had a legitimate concern in the case of NYLF/tech, but I will see my family again in a few weeks during spring break.

Well, I'm glad that is out of my system. I feel much better (and have my composure back as well.) I am considering not publishing this post, but I have a feeling that that would undo the "getting it out of my system" that has been done by writing it.

P.S. If you're clever, you can read the redacted part of this post.

Validating Input

noreply@blogger.com (James Cassell) — Sat, 23 Feb 2008 04:37:00 +0000

When writing code, always validate the input. This may seem like common sense -- and it is under most circumstances -- but in one particular case, it is not. In the case of a computer science class when the instructor guarantees proper input, it is very tempting to not validate the input and simply assume that it is correct. This will save you a little time on each assignment, but is not worth it in the long run. I found this out today. I had a computer science project due at midnight last night. I didn't have it done on time, so I had to waste my remaining late day on it. I spent nearly 24 hours trying to debug my program that should have been working.

When I was debugging, I kept seeing things that could go wrong with improper input, but remembered that I only had to deal with proper input. My program seemed very brittle; the difference between a segmentation fault and the program running fine (but exiting early) was the difference between a break; and a continue; statement. It was at this that I randomly noticed that there was one line of the input was causing the crash. The input was improper despite assurances of the contrary the instructor.

I checked on-line to verify that I didn't mistakenly modify the file. Sure enough, the file on-line was correct, but the date on the on-line file was more recent than the date on my file. Apparently, the teacher noticed (or was informed of) the mistake, and updated the files on-line. What he did not do was send a general notice of the mistake and subsequent correction. Because of all this, I wasted nearly 24 hours of my time as well as a "late day" for turning in homework.

The moral of the story is that one should always check his input even if it has been guaranteed that it will be correct. The benefits of checking the input greatly outweigh the costs. Besides this, it is simply good practice, especially for any code that will be used in production. I had to deal with this when I was writing the contact form for my site; most of my time was spent writing the validation code to prevent any security problems.

Context in Perception of Scents

noreply@blogger.com (James Cassell) — Thu, 21 Feb 2008 16:58:00 +0000

I noticed something interesting just now. How you perceive a scent depends heavily on where you believe the smell is coming from. Someone sat down next to me, and I thought he smelled like a dead animal. This was quite disconcerting. Shortly thereafter, I looked over and saw that he was eating a turkey sandwich. Immediately, the odor of a dead animal was gone, and the smell of a turkey sandwich was present.

I think it is interesting how the brain interprets the same odor differently depending on where it believes it originated. I would imagine this is somewhat similar/related to how taste is heavily dependent on smell; you can't really taste anything if you have a cold or a stuffy nose.