James Cassell's Blog

Problem

About a two months ago, I had a problem with Windows. I got the following error: "Windows could not start because the following is missing or corrupt: \Windows\System32\config\SYSTEM" I went to the Help Desk at the VCC, and surprise, surprise, after several hours, they weren't able to fix the problem.

About a week later, solved the problem myself, and am documenting it for you here.

Solution

So, the solution is to boot into a recovery environment, and to copy the file at "C:\Windows\System32\config\RegBack\SYSTEM.OLD" to "C:\Windows\System32\config\SYSTEM", making sure to back up the old "C:\Windows\System32\config\SYSTEM" first, just in case. As far as "recovery environments" go, I just booted into Linux, though a Live CD, or even the Windows installation disc would work just as well.

This same problem happened to me about two weeks ago, and this same procedure saved my system again.

There is a Microsoft KB article that describes how one could solve the problem for Windows XP, but that wasn't much help for the same sort of problem on Vista.

Labels: annoyances, fixes, rpi, technology

The other day, I decided to re-install XP. I have a triple-boot system; on my ThinkPad, I have Vista, XP, and Fedora. I told the XP installer to delete the partition that had my old install of XP, and when I told it to put a new one in its place, it told me that I already had four primary partitions.

My partition table was a follows: first primary partition: Vista; second primary partition: XP; third primary partition: boot partition for Fedora; fourth primary partition: extended partition which holds: 2 encrypted partitions for Fedora.

After the XP installer touched my partition table, the I could only boot into Vista. GParted saw my entire disk as "uninitialized," or basically, empty. At this point, I was in a slight panic; I had a lot of important stuff in my Fedora partitions.

My eventual solution was both tedious and dangerous. I basically edited the partition table by hand, using the command line tool sfdisk. I did this using the Fedora 9 Live CD. This time, I had gparted create an empty NTFS partition, and I told XP to just use that, and I let it format it when it asked, which turned out to be a mistake. This caused it to mess up my partitions again, and I had to use sfdisk to set them straight. I now have a working setup, as I had before re-installing XP.

The moral of this story happens to be the title of this post: Never let Windows XP touch your partition table.

Labels: annoyances, fixes, hardware, random, technology

I have been having a very intermittent problem in Linux where my Ctrl and Shift keys would stop working. This prevented me from typing a question mark, as well as preventing me from entering my passwords when they were required. (All but my most insecure passwords require the use of the shift key.) Additionally, this breaks many, many keyboard shortcuts. I had noticed that this problem seemed to show itself whenever I used a program that captured the mouse and keyboard, such as a remote desktop application, or a virtual machine application.

Today, after having failed many times in the past, Google helped me find a solution that didn't require rebooting my machine (which was my only-known solution previously.) In a forum somewhere, someone said that fidgeting about with setxkbmap could sometimes help. It turns out that he was correct. If this happens to you, you can type, "setxkbmap dvorak; setxkbmap us" (without the quotes) into the command line. It worked very well for me, but your mileage may vary.

(Now, if only someone were to make a post like this whenever they solved an obscure computer problem. It would make Google's job much easier.)

Labels: annoyances, fixes, hardware, technology

This past Saturday, I woke around noon to the sound of my cell phone. Strangely, it wasn't a telemarketer calling to tell me that the non-existent warranty on my non-existent car was about to expire. One of my friends was having a computer problem, the likes of which I had never heard before. One thing that I have noticed semi-recently is that it is difficult to troubleshoot an unknown computer problem over the phone. (If it's something I've run into before, that's a different story.)

Technical Aspect

Not that it will interest the reader, but I'll describe the symptoms of the problem anyway. (Maybe someone who has a solution will post it in a comment.) Windows Vista would boot fine to the login screen. After typing the password was when the problems started appearing. The "Welcome" message would show for a few seconds, then, when the desktop should have appeared, only a royal blue background appeared. At this point, the mouse was functional (i.e., it moved around,) but there was nothing to click on. It seemed as if explorer had never started. All of the normal approaches to diagnose such a problem (e.g., Ctrl+Alt+Del, Ctrl+Alt+Esc, etc.) were useless. I asked on IRC, but no one had any solutions. Neither did Google. As a side note, it would boot into safe mode.

Eventually, we were able to get the desktop to come up by going into msconfig and disabling all of the startup items as well as all of the (non-essential) services (as defined by msconfig.) Upon re-enabling the services, we were able to get a functional desktop for about one boot, but when we rebooted, the initial problem re-appeared.

I didn't want to try the same solution again because, as Einstein said, it is insane to do the same thing over and over again and expect different results. My next suggestion would have been to get the computer re-imaged. We had been working on this problem for over five hours by this point, and I didn't want to send my friend away having wasted so much time. Since the Help Desk wouldn't be open until the following afternoon, I proposed another solution. Last year, I had taken a backup image of my computer the day that it was issued. I still had this backup, (that consisted of six DVDs,) and proposed that we do a restore from this image. We did so, followed by downloading all of the updates that had been released since. This second option took about six hours. The system was now in a pristine state.

Human Aspect

As can be inferred from the above, this ended up being an all-day event. Some may exclaim, "what a boring way to spend one's Saturday!" I look at it differently. In addition to the fact that "...we know that all things work together for good to them that love God..." (Romans 8:28, KJV), I can't think of a better way to spend a Saturday than getting to better know my friends. In case you know nothing about humans, people don't sit and stare blankly at one another for more than eleven hours, while waiting for a computer to do its thing. Another of my friends joined us about half-way through, and hung out until the end. I met both of these friends at Silver Bay, where, many will agree, the best times since heading off to college, have taken place. This opinion was voiced several times through the day.

While this day may have been a bad day for the victim of the computer problem, it was one of the best days that I have had since returning to Rensselaer. The only thing that I would change about the day is my allowing the conversation to be steered to my planned activity for the day: sleeping into the late afternoon. This caused my friend to feel bad for waking me, and, in turn, made me feel guilty for causing this bad feeling. This could become a vicious circle. Aside from that, I'd say that the day was an excellent unexpected adventure!

Labels: college, fixes, life, technology

This semester, I am taking 23 credit-hours. An interesting thing is that they are all technical classes, which could turn out to be a bad thing, or a good think. I don't know yet. These are the classes I'm taking:

Navigation is my Navy class, and I have a feeling that it will be the easiest Navy class that I will have the chance to take, given its technical nature. We actually have a civilian taking the class because that which is taught also can be applied in the civilian world. (Not that that isn't true for the other Navy classes; it is simply more obviously true for this class.) So far in this class, we have started with the "Rules of the Road," which is basically how to drive on the water.

Introduction to Engineering Design looks like it will require the most work out of me this semester. This is a "design" class, which means that everyone has to design and build something, which, in this case, happens to be a robot (for which we haven't received the requirements. There will be a project done on an individual basis as well as one that is done as a team, the latter of which will count for most of our grade. I found out the answer to a requirement oddity the first day of Introduction to Engineering Design: Professional Development 1 is part of the course. In the requirements for my major, "Professional Development III" was listed as a requirement, but I and II weren't.

My Data Structures and Algorithms teacher has a very heavy accent, and is quite difficult to understand. This will almost certainly be my most difficult class in terms of subject matter. From what others who have taken the class say, it requires many hours of work, and the concepts are somewhat difficult to fully grasp. This difficulty combined with my instructors heavy accent will probably make this class a difficult challenge.

One interesting thing that I noticed between the three other classes, Embedded Control, Computer Organization, and Computer Components and Operations, through yesterday, they were all teaching us the same material, in an attempt to get everyone to a common baseline. This material was, for the most part, the binary and hexadecimal number systems as well as a discussion of number systems in general. Having built a calculator from scratch as a high school freshman as well as my geek mentality, I already knew this material (as did many in the class, to an even greater extent than I.) The school administrator at the time told me that I was doing college-level work, and, low and behold, in one of these classes, we will be doing a project very similar to my winning high school science fair. This easy-going spurt ended abruptly for me today, as each of the classes started on new material, and diverged to cover material specific to that class.

In Embedded Control, we will be programming micro-controllers, and messing with electronic hardware. By the end of the semester, we will have automated things that range from RC cars to small blimps (which have been provided to Rensselaer by BAE Systems.)

Computer Components and Operations looks like it will have the most material with which I am already familiar, discussing how computers do what they do. I had explored this topic somewhat deeply during my high school years.

Computer Organization -- actually, I'm drawing a blank for any specifics of this one. I'm pretty sure that anything that was covered, I already knew, and dismissed as "no need to re-learn this." (Which reminds me of a "sea story" from the beginning of last semester, but I'll tell that another day, if someone asks me in person.)

Update: 1 Sep 2008 @ 1832 EDT (UTC -0400): Now that I have gone back to the class, I remember what it is. The professor has set up a Linux server for us to complete our assignments. The first topic that we are covering is an Introduction to Unix and C. Both of these I am familiar with to a certain degree, which is why I was drawing a blank earlier. (This strongly goes along with my aforementioned "sea story.")

Overall, this semester, no one class looks like it will be particularly hard; my only concern is that they will present a very large amount of work.

Labels: annoyances, college, life, navy, rpi, school, technology

Last Spring, there was a "lottery," where the order in which students would get to choose their rooms was chosen. I didn't get too bad of a number, but by the time my turn came around, my preferred choices for a room were gone. (These were Davidson, or Nugent Halls.) I ended up with a small single in the Quadrangle, otherwise known as "The Quad." One thing that I declared to be a requirement for my room was air conditioning. The Quad does have air conditioning, which I am happy about.

When I first got into my room, I was really disappointed at how small it really was. There was almost no room to move around. I had planned to mitigate the small space by lofting my bed, and placing my desk underneath. This turned out to not be an option for a couple of reasons. First, my bed has drawers built-in under the mattress, which loses me two feet of vertical space. Second, the ceiling is only eight feet high, and the regulations state that there must be at least three feet of clearance between the top of the mattress and the ceiling. The combination of these two would have left me with only about three feet under the bed, which is insufficient to fit a desk. Another peculiarity of the room is that it is more narrow than it is tall.

When I got into the room, the bed and the desk were parallel, with about 2 feet between. This was not sufficient space to pull my chair out from the desk and comfortably sit in it. What I ended up doing was to re-arrange the furniture in the room. I rotated the bed ninety degrees, which was in and of itself a challenge, as the room wasn't wide enough to properly do so. I pushed the bed as close to the window as I could, which was several feet away because the air conditioner kind of got in the way. I have my servers as well as printer in this space between my bed and the window. Now that I have done all this re-arranging, I have a consolidated floor space, where I can comfortably pull out my chair to sit in.

At this point, I am satisfied with my room, and my initial concerns have been mitigated. I am really enjoying the air conditioning.

Labels: annoyances, fixes, life, rpi, school

Today, I am no longer a teenager. This makes me somewhat sad, but looking at the definition of teenager, and especially the lower realm of qualification, I'd say that I don't really fit the description. I'm not sure that I really ever was the stereotypical teenager. I don't remember behaving as stubbornly as I see some of the few teenagers in my life behaving.

At any point in my life, the "level" above (or ahead of) me seems to be quite far off. When I look at the "level" behind me, (or rather the people that could represent this "level,") they seem to be very young. When I look back at myself when I was at that level, not much seems to be different than the current "level"; it seems as if my "level" is a constant that is just being redefined as I go through life.

Along the same lines, my grandfather recently said to me that he thought that I had "matured very nicely" (or something to that effect.) Now, I don't know what the proper definition of "maturity" in this context is, but it doesn't seem to me that my thought processes have changed much in the past several years. Rather, I think that I have just discovered ways to speak my mind without causing controversy (which is probably known as rhetoric), and have chosen to hold my tongue much more often that I had when I was much younger. (I can think of at least one prominent time that I should have held my tongue, but this particular instance was more than a decade ago.

Notice: I started this post on my twentieth birthday, but never got around to pressing the "Publish" button until now, three months later, 28 Aug 2008 @ 2057 EDT (UTC -0400).

Labels: life, observations

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

Labels: college, life, navy

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.

Labels: observations, technology

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.

Labels: observations, technology

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.

Labels: annoyances, news, technology

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.

Labels: annoyances, life, observations, rpi

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.

Labels: life, observations, technology

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."

Labels: rpi, technology

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.

Labels: observations