MS Comic Chat Helper for Freenode

MS Comic Chat Helper for Freenode in action MS Comic Chat Helper for Freenode in action

Microsoft Comic Chat (MSCC) has been of interest to me for a while, but it crashes whenever it joins a room on Freenode. Inspecting messages from Freenode's servers (Wireshark made this very simple!) caused me to suspect that they are caused by ircd-seven's distinct formatting. As it turns out, MSCC expects whitespace and delimiters in some places, and crashes when there isn't any to be found.

I wrote a Python 3 script which reformats Freenode's messages and relays them to a local address, allowing you to chat on Freenode rooms with MSCC. To avoid sending passwords thru the airwaves in plain text, the script connects to Freenode with SSL, SASL. This means that you must have a registered account to use the script.

Instructions can be found in the README and USAGE sections on the script's header. The script is available for download on the following pages:

Dropbox
Pastebin

Usage notes:

  • No nickname tab-completion
  • Populating large rooms takes a non-negligible amount of time. Roughly 100 users per second.
  • When a link is clicked, MSCC tries to launch a browser inside the main window. This fails (for IE and Firefox) and launches a normal browser window with glitched borders.
  • In Comic View, messages are added to
  • Comic View is inalterably uppercase-only.
  • In Comic View, touch-to-scroll corrupts the strip. Scrollbar buttons, pgup/pgdown, arrow keys can be used to scroll and fix corrupted views.
  • In Comic View, short messages occasionally get covered up by larger speech bubbles (although they are still visible in the script terminal, of course.)
  • In Comic View, multiple active users in large rooms may be assigned the same character. (More characters can be installed)
  • Comic View looks ridiculously cool.

Why Use Windows

I use Windows by choice.

I was a diehard Linux nazi until my first job where everyone used Windows. Initially I was appalled. I plastered my work computer with ``productivity software'' to morph the system into something more like my personal laptop. I changed everything I could think of: window managers, the font renderer, widget colors, the registry, keyboard shortcuts, the file manager, drive names, etc. Most Linux distributions expect you to make these choices on installation, so I was horrified to see that they didn't exist at all in Windows.  There is a subculture which revolves around changing the settings of computer software, and I was a part of it.

Within the first week, the computer was in such a poor state that no one, not even I could make any sense of it. Behavior of modifier keys was unpredictable so all actions had to be done with the mouse. Windows of running programs frequently 'disappeared' even though the tasks were still running. The system got intolerably slow after prolonged use, and had to be periodically rebooted. "What have you done to this poor computer" a coworker told me.

Now I leave every default untouched unless absolutely unavoidable. I use IE (Firefox with no addons when that breaks), Visual Studio, Windows Photo Gallery, etc. Most of the less common software I must use is run out of a folder in my home directory. Now everyone can be productive on my system and the only thing I have lost since switching is the smug self-righteousness of Linux veganism and Lifehacker articles.

There is no default on Linux, so there can be no expected behavior. That is why I use Windows.

Notes on Transferring from Community College to Math

Two years before completing my Math degree at NCSU, I went to Wake Technical Community College. My goal was to get as much general education and science out of the way so in preparation to focus on math post-transfer. This plan basically succeeded, but had several major repercussions:

  • My community college didn't offer any major prerequisites to theoretical math. Some classes are just not there. In particular, the bottleneck 'Intro To Proofs' course was not offered. This meant that after transfer I was left with 4 semesters to find a focus area and pick up whatever advanced math I could.
  • Some graduate math sequences I would really have liked to take at NCSU (for example, ones in functional analysis, differential equations, mathematical statistics and probability theory, numerical methods) were simply not available to me since I just didn't have enough time. None of this is outside of the realm of self-learning, but nothing beats taking a class.
  • Some classes are just not there. For example, electrical engineering at NCSU has long sequences that are supposed to start in sophomore year, and none of them are offered at community college. For these degrees, staying two years at community college puts you at least year back. If I recall correctly, the fastest you can graduate in EE after transferring from community college is something like 4 and a half or 5 years even if you Slam Yourself with course work.
  • By negligence I ended up taking a few general education classes that didn't transfer, or that I didn't need to (for example, General Biology). They were worthwhile classes but getting more science requirements (e.g. modern physics, chemistry) out of the way instead would have given me time to take an extra math class.
  • All 4 semesters after transfer were extremely interesting since I had basically no bogus general education courses left.
  • At NCSU, you get credit for transfer classes but your grades don't count. This means that the only thing that counts towards your GPA is the meat of the degree, which is overwhelmingly positive if you like what you're studying.
  • It's cheap.

My thesis is that if you're going to transfer to math from community college, front-load everything as much as possible. Get all your science and general education out of the way ASAP to give time for deeper classes. I would recommend taking your 'Intro to Proofs' class, which is fairly universal for math degrees,  the summer of transfer or sooner if possible. Interestingly, by this strategy the optimal community college schedule towards math looks largely the same as if you were aiming for physics. I haven't checked but I imagine it would be largely the same for chemistry as well.

Beginning at community college did not detract from my degree one bit but there are some cool things you can do with 4 whole years at a university.

ASUS T100TA use notes

My X220's screen went out a few weeks ago and I needed a new laptop to fall back on for school. Best Buy had a ASUS T100TA on sale for cheap so that is what I switched to. The switch was virtually painless and I was productive within the day I started using the computer. However I have run into a few oddities during usage.

The 32GB internal drive is suffocating. A 64GB version of this device exists and I thoroughly recommend others to opt for it. The Windows folder, page file and hibernation file are the largest items on the disk, leaving about 8GB to spare with the complementary Microsoft Office suite installed. I needed to run TexLive, Matlab and Maple to survive the semester, and the disk simply does not have enough space to accommodate them. All these programs and even Team Fortress 2/Steam run fine off an external drive, but I can only run them when the system is docked to its keyboard, where the USB port is.

I have heard there are versions of the dock with an integrated 500GB drive. I didn't get this kind, and there is no place for a hard drive inside of mine.

Out of the box, the battery drained even when the system was plugged in. I suspect that this was caused by the Windows Search service's continuous processor usage. I disabled the service and now my system charges during usage like it like it's supposed to. Search runs at fine speeds with the service disabled.

By default the system's touchpad is intolerably laggy. Delay was so severe that many swipes failed to register entirely, even with every gesture disabled in ASUS's `SmartGesture Control' program. I could tell hardware wasn't the problem since even the slightest brushes were displayed in the touchpad's notification icon. The problem went away the instant I uninstalled the `ASUS SmartGesture' program. Without the program you lose all gestures except for 'tap to select, double tap to drag,' but you gain a usable touchpad.

Aggressive preprocessing makes the system's microphone unusable out of the box. It can be turned off using the Realtek Audio Manager located in C:\Program Files\Realtek\Audio\AP\RtkNGUI.exe In 'Voice Recording' switch to 'Disable All.'

Within a week the speakers started generating a really loud feedback-like noise. The symptom is demonstrated in this video: https://www.youtube.com/watch?v=G9pB8rGqlwY  I still don't understand why this issue arose, but I fixed it by reinstalling the sound card's drivers in the device manager. More information about this is issue is available here: http://www.reddit.com/r/fixit/comments/23vlwn/whats_wrong_with_my_laptops_sound/

There are a few annoying ASUS programs that run in the background, such as the 'AC Reminder Service' which apparently notifies you if you try to flash the system ROM without the laptop plugged in. It uses up almost no resources so I just try to forget that it is there. An 'ASUS Registration Reminder' program is also set to run on startup. Windows reports that it slows things down so I disabled it.

The computer uses Windows' new EFI-based boot procedure. Out of the box there is no option to boot to USB from power-on that I am aware of. There is a different procedure to installing Linux on the system but it appears that others have figured out how to do this. Even if technically possible, dual-booting to Linux is probably not an effective choice since onboard disk space is so limited.

Even though the computer contains a 64-bit CPU the preinstalled operating system is the 32-bit version of Windows 8.1. This did not create any real problems but I am still confused as to why they did this.

The system's screen resolution is 1368x768; you get two extra columns. Everything looks awful in the more standard 1366x768. Fortunately the Intel graphics driver automatically installed by ASUS's driver update program handles the strange resolution fine.

If I run into any more issues I will update this post with them. All the major problems I have had with this system have been fixable. I am thoroughly impressed by how usable it is as a full-time laptop.

Optimizing the transfer charactaristic of a resistive-transducer-based voltage divider for ATD reads

Many applications of thermistors and other resistive transducers involve reading their voltage into a microcontroller through an ATD converter. Setting this up involves designing a circuit that shifts and contorts the transfer characteristic of the transducer into a range the ATD accepts.  While circuits that map precisely to an ATD's range are well-known (TI paper), the output of a simple resistive voltage divider may map the transducer's output to enough steps of the ATD's range that sufficient precision is attained for the application. A major benefit of using a voltage divider is it's simplicity; the only additional components it needs are a source (I use VCC from my microcontroller), a resistor, and possibly a diode if overloading the ATD is a concern. This post demonstrates how I calculated the best static resistance to use to obtain the widest possible voltage range for my thermistor in this circuit.
If we connect a \(V_S\)-volt source in series with a variable resistance \(R_T\) and some constant resistance \(R_K\), the voltage drop across the transducer will be \(\frac{R_T}{R_T+R_K}\cdot V_S\ \ \text{V}.\) Conveniently, this function is monotonically increasing along positives, meaning maximum voltage drop will occur when \(R_T\) is at it's highest, and minimum voltage drop when it is at it's lowest. The span of voltages the transducer will take on is then:

\[|V|(R_K) = \left[\frac{R_{T_\text{max}}}{R_{T_\text{max}}+R_K} - \frac{R_{T_\text{min}}}{R_{T_\text{min}}+R_K}\right]\cdot V_S \ \ \text{V}\]

Since we want to maximize this value, we must differentiate it and find the positive root for variable \(R_K\):

\[\frac{\partial |V|}{\partial R_K}=\left[\frac{R_{T_{\text{max}}}}{(R_{T_{\text{max}}}+R_K)^2}-\frac{R_{T_{\text{min}}}}{(R_{T_{\text{min}}}+R_K)^2}\right]\cdot V_S = 0\]

\[\ldots \Rightarrow R_K = \sqrt{R_{T_{\text{max}}}}\cdot \sqrt{R_{T_{\text{min}}}}\Omega\]

The thermistors I am using fluctuate between 5 and 10kΩ under normal operating conditions, so my optimal resistance would be \(\sqrt{5}\cdot\sqrt{10}\text{k}\Omega ,\) or about 7kΩ. They will be powered by my microcontroller's built-in 5.12V source, so the thermistor will span \(\left[\frac{10\text{k}\Omega}{10\text{k}\Omega+7\text{k}\Omega} - \frac{5\text{k}\Omega}{5\text{k}\Omega+7\text{k}\Omega}\right]\cdot 5.12 \text{V} \approx 0.878 \text{V}.\) The ATD module reads from 0 to 5.12V in 0.005V increments (10 bits), so I will get \(\lfloor\frac{0.878}{0.005}\rfloor=175\ \text{steps}\) of accuracy. Pretty good for a simple voltage divider!

To ensure that a power surge doesn't fry the ATD, I have installed a 5.1V Zener diode in parallel with the thermistor's leads where the ATD is hooked up.

Programming a 68HCS12 in Assembly

Recently I have been working on a research project at the NCSU OSL to design, construct and test a blackbody radiator for the calibration of IR cameras. It will essentially be device that holds a 4*4in surface at a constant temperature using thermistors to read the temperature and thermoelectric coolers to sustain the temperature. These components will be interfaced by a Technological Arts NanoCore12 prototyping board, which is built around a Freescale 68HCS12, a descendant of the old Motorola 6800.

My supervising professor said that assembly language is best suited for this project, so over the past several weeks I have been picking up this architecture's dialect. It's been my first exposure to assembly so I've hit a few speed bumps along the way, many due to my being stuck in a different frame of mind coming from higher level languages like C++ and Java. There is a stark difference in workflow coming from purely software-based environments with step-through debuggers and loads of example code to one where the only relevant documentation is buried in a maze of manuals. Here is a list of the most important things I've learned so far from working on a prototyping board:

1) Check and re-check all your bread-boarded circuits until your eyes are sore before you supply voltage to them, and go ask for help as soon as you get stuck.

At the beginning of last week I shorted some leads on a live board for several hours, but didn't cognize that I was doing so until much later. I spent the remainder of the week glazing over extremely basic code to blink an onboard LED on and off with respect to an input voltage. To my dismay, the processor started overheating to egg-frying temperatures under no load and the LED wouldn't turn off consistently. After way too much time of not getting anywhere I took the problem to my professor and he concluded in under an hour that the board's Analog to Digital module was fried, along with some other parts. This colossal time sink would never have occurred had I just installed some resistors near the voltage source (or had just went and asked my professor sooner).

2) Simulators are not debuggers.

One of the most indispensable tools I have used in this project is a processor simulator similar to the one found here. For a while I treated this tool like an on-board debugger that I so long for in the assembly environment. However, since the simulator only reproduces the architecture's processing instructions and not any processor modules, the simulator's response doesn't always perfectly correspond to what the board's actual behavior, especially in situations like #1. My workflow so far has been to get the code working in the simulator first, then start mucking around in module documentation when it doesn't work in real life.

3) Change only one thing per trial during experiments.

After I got a new board to work on, my blink code still didn't work. I somehow convinced myself that I wasn't properly implementing subroutine returns, and that the ATD module was misconfigured. I mangled these areas of my code in all kinds of different ways to try and figure out what was wrong. Out of desperation I decided to mentally step through every single line of code and think about the operation's definition in the architecture documentation, and the description in module documentation of the register the operation acted on. Only after grilling every relevant codeblock line-for-line in this manner did I realize that that it was because while the ATD output was unsigned, I was comparing values using a signed check (BLE/BHE instead of BLS/BHS). Virtually no abstraction happens within the syntax, so there is nothing to stop you from comparing apples to oranges since they are all basically just bits. In retrospect, I can't really think of how I would have found the problem without going through that process, but I would have arrived to it with much less grief if I had tried the systematic, controlled approach first.

4) Make your source code verbose.

6800 assembly is the ugliest language I have ever seen in real life, and I'm sure most other assembly dialects are about the same. It is difficult to write readable assembly for many reasons. Everything is in structured in columns, but consistent delimiters are not enforced (e.g. Python) so if you copy and paste your code anywhere there's a fairly high chance your lines will get stretched all over the place. The length constraint (around 6 chars) of labels, your only way of assigning names to things, is not long enough to allow for anything descriptive. I am still developing my style but so far I have settled on a few no-brainer guidelines:

  • Keep your source code along with the processor's documentation files and for every line you write to a settings register, add a comment with the relevant documentation's filename, page number, and the options you meant to set.
  • Every time you label an acronym, add a comment that expands the acronym.
  • Keep everything in blocks with comments above them. You can't indent your code, but at least you can indent your comments.
  • Try and structure things like a sane language. Encapsulate what would normally be a function using labeled subroutines. Describe each subroutine with a comment.
  • If you run out of good names, start a name table in a separate file.
  • Comment everywhere!

I have wasted a good deal of time trying to decipher my own code because I though it was obvious at the time of writing. You can save yourself by writing comments better comments than I did!

Learning to write assembly has been very rewarding so far. Hopefully my experience will help other beginners gain some insight on how to approach coding in assembly language.

UZBLSMS: A way to browse the web via text-message

UZBLSMS is a basic Python utility you can run on a Linux computer that allows you to view and control a web browser via anything that is capable of sending SMS messages and receiving MMS. This effectively means that with this software, you can browse the web through a dumbphone without a data plan, just as long as you have unlimited texting. Even though my original intention was to use it with the UZBL browser, you can really use it with any software you would like as long as it can be controlled entirely by keyboard shortcuts.

Most of its functionality and warts are discussed in the README, but I'll reiterate the basics right here. Here's how it works:

  1. You configure the software by changing uzblsms.py, then run whatever piece of software you want on some X display.
  2. Run uzblsms.py with the X display in the parameters.
  3. Text a series of keystrokes to your GMail account. (Phone-specific, but it can be done on the LG Cosmos by typing an email address into the recipients field)
  4. uzblsms.py mimics your keystrokes on the X display, waits a few seconds for things to settle, screenshots the display you specified, then sends the screenshot to your phone via a SMS gateway. (Carrier specific. Most major carriers have them)
  5. Repeat!

I have used this software to update my Facebook status in a place with no reliable internet reception! In my experience, lag is not as terrible as you would expect. I generally received screenshots about 10 or 20 seconds after the keystrokes were sent.

DOWNLOAD LINK Ver. 0.1a

This code is published under the FreeBSD license.

Known issues:

  • It stops accepting commands after being idle for a period of 30 minutes or so. I am almost certain this is due to some trivial X-server misconfiguration, but I could not figure it out conclusively.
  • It relies fairly heavily on external dependencies like ImageMagick.
  • For some reason I chose to write it in Python 3. In retrospect it would probably be good to have started with a more established language like Python 2.

NCSU Registration Process

One can draw parallels to registering for classes at North Carolina State and spawning on the wrong side of the Hoover dam. For future reference, here is a list of all the 'gates' that had to be lifted before I could register for Summer II 2012 classes. Most, if not all of these probably apply to any incoming Freshmen working towards a major.

Gate 1) Admission and Initiation: You need to get your application accepted to before anything. Once this is done you should have a WolfPaw account and a MyPackPortal thing set up.

Gate 2) Advanced enrollment fee: You pay $200 or whatever to confirm that you are indeed going to NCSU, not anywhere else. I payed through WolfPaw although there are probably redundant facilities for it in the MyPack Portal.

Gate 3) Freshman Matriculation: Now that you have entered all your accounts and stuff, the NC State needs to register them into it's system. You have basically no control over when this happens so it's up to the administration. Try asking someone at Admissions.

Gate 4) Transfer Credits Matriculation: Have college credits from high school or community college included in your NCSU application? Even if you had gotten your official transcripts sent to NC State quite a while ago, they won't be associated with your account until some internal date a set time before the semester starts. Again, this is up to the administration.

Gate 5) Enrollment Date: State makes you wait until a certain date before you can enroll for classes. The day and time of this 'enrollment date' depend on how many credits you have. The incentive behind this is that they want to give the first choice of classes up to people who have almost completed their degree; how horrible would it be if you were a Senior with one Fresman-level class left that you couldn't get into because it filled up? Coming in as a Freshman with no credits, you are basically the bottom feeder of all enrolling parties. Once you have passed Gate 3, you will be able to see your enrollment date on the MyPack Portal.

Gate 6) Enrollment Appointment: Besides the enrollment date, you must also get a seal of approval from your undergraduate adviser for any courses you wish to take. However unnecessary it may seem, this step is mandatory. Check on your department's sub-website to find out who your adviser is, then set up a personal meeting with him/her. Note that this can be done before your enrollment date has passed, but not before Gate 3. The meeting will go more smoothly if you prepare a class plan ahead of time through the MyPack Portal's 'Plan of Work' facilities. [You will probably want to wait until after Gate 4 to make your class plan].

Gate 7) Placement Tests: Some classes like introductory mathematics, engineering, computer science or chemistry require you to take a remedial course (Like ECE115 or CH111) to account for what knowledge may have fallen between the cracks during High School or AP classes. Thankfully, NC State offers some online Pass/Fail tests that will place you out of such classes. These exams may only be taken once, although they won't be a source for much of your stress provided you know the material. Perhaps this is something to talk about during the meeting you have with your adviser.

I jumped through the first six hoops over the course of several months, and am now studying for a few of the tests in Gate 7.

Custom Label Colors in Gmail

Some of you may have noticed that after Gmail's theme switch a few months ago, users are now unable to easily specify the color of mail labels.  Instead we are presented with a limited and somewhat ugly palate:

Gmail label color palate

Gmail label color palate

In my fooling around with the internet I discovered that you can specify custom colors in RGB using nothing more than some simple HTML injection.  The palate is displayed as three tables, each cell with it's own background color. It turns out that the color sent to Google is determined by the background color as specified by the client version of the web page. There is nothing stopping you from changing these values.  Here is a demonstration of how you could perform such a change using Firefox and Firebug:

Now your inbox can be less ugly.

OTF Ghostscript Fonts

Ghostscript is a free software suite that provides libraries to help your computer explain your printer how you would like things to show up on a piece of paper. Somewhere along it's development, a typography company called URW++ decided to contribute a sizable pack of fonts to the project. The group of fonts is very nice because it includes near-replicas of typefaces like Helvetica (Nimbus Sans L) but, unlike Helvetica, is free. Unfortunately, it looks like not very many people have taken interest in the collection so it hasn't been distributed much outside of Linux distributions.

I am currently stuck on a Windows machine so I don't have easy access to these fonts. In my rummaging around the internet I couldn't find any copies of the typefaces in a format that would install on Windows so I decided to make some. I took copies of the fonts from a Linux distribution and converted them to OTF. Here is the resulting font pack:
Direct Link
Mirror

The tarball contains the following families:
URW Bookman
URW Century Schoolbook
URW Gothic
URW Nimbus (Sans, Mono, and Roman)
URW Palladio

Because they are all in OTF, they can be installed on Windows. They may look a little wonky in your word processor but that is most probably because of a rendering issue; if you are super anal-retentive and want to be sure, convert your document to a PDF or SVG and examine the font in that format before printing.