Other articles


  1. Random File Permissions

    If we create a new file in Linux, why are the default permissions random?

    At the risk of repeating myself, suppose I run the following C program three times, where I deliberately omit the permissions (or mode) argument in the open function:

    #include <fcntl.h>
    
    int main()
    {
        int fd, ec ...
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  2. Default File Permissions

    What are the default file permissions when creating a new Linux file?

    Most documentation describes the permissions as "unpredictable", which usually means quasi-random. If I create a new file in C and compile it using gcc, then permissions do appear to be random:

    #include <fcntl.h>
    
    int main()
    {
        int fd ...
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  3. Horizontal Mouseover Submenus in CSS

    In this document, I provide instructions on how to make a horizontal navigational bar with mouseover submenus using CSS. This is also an attempt to documents things as I learn, so expect frequent updates.

    HTML example template

    In the example below, we isolate the components within a top-level nav element ...

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  4. Black-Scholes Derivation

    Introduction

    I found it difficult to follow many of the derivations of the Black-Scholes option pricing formula. Most get the stochastic details correct, but they all seem to be a bit loose in their definitions of the portfolio. So this is my attempt to document a derivation that I could ...

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  5. Scuse the mess

    Apologies for the messy website. I am experimenting more with Pelican and trying to create my own website theme. That means not only learning Pelican in more detail, but also Jinja2 and even basic HTML and CSS, which I haven't seriously looked at since the 90's.

    The results ...

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  6. Persona: Aegis or Aigis?

    Aigis

    Sweating through Persona 3 Portable has turned me into a Persona fan, and one of the more interesting characters is the Anti-Shadow Suppression Weapon, Aigis. But there is one thing I find confusing about her: How do I spell her name??

    Since the character was developed in Japan, perhaps the ...

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  7. "Digital: A love story" emilia.core message

    I just finished playing Analogue: A Hate Story" by Christine Love, and am now going through the spiritual precessor "Digital: A Love Story".

    At one point, you get a mysterious message from another user after a system crash, including a binary sequence, which is in ASCII. I thought it was ...

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  8. Avoiding Utility Classes

    My journey from science to computer science consists mostly of very small victories, so I don't always recognise everything that I've learned as it happens. But in C#, my first serious attempt at object-oriented programming, the lessons are occasionally more acute. In the space of about a week ...

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  9. MPICH2 and bcastlength failures

    After installing MPICH2 on my workstation, it kept consistently failing the bcastlength test (something about detection of broadcasting a too-long array, see here. After scouring Google to see what was wrong, I found nothing. Eventually, I broke down and subscribed to the mailing list, intending to ask the community. But ...

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  10. Evo (Java) white screen problem

    Since everyone in my work team is located at different cities, we use videoconferencing for occasional meetings. The software we use is Evo, which is a java-based application that has pretty good quality and supports multiuser conferencing. Today, I had a problem where the application would simply not open. All ...

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  11. Useful Drupal Module

    Lately I have been struggling to learn how to use a Drupal site effectively. The fact that I can get it running at all shows that it is a mostly painless process; typical LAMP stuff. But it has been hard to find the right modules for the job.

    The main ...

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  12. Threading in Thunderbird

    I mostly use GMail for personal emails, but I still access my work email through Thunderbird. In fact, I often tell myself that the days of the email client are numbered, and I should already be doing everyone on the web. I have occasionally considered piping it through GMail, but ...

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  13. Heap or stack?

    After a visit to UNSW last Friday, the subject of using stack or heap memory for a climate model came up, with my host promoting use of the stack for all variables, including basic field variables like velocity or temperature. The issue surprised me a bit because I had never ...

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  14. YAML, JSON and human-readable configuration files

    There are many headaches involved in using climate models. One is usually required to compile and build the programs themselves, and there is usually a dependence on at least a few external libraries, such as NetCDF or MPI support. Data formats can be peculiar and poorly documented, and modifying the ...

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  15. Home again

    We've finally returned home from our trip about three weeks ago. Unfortunately, I also became terribly sick after arriving home, which meant that I was out of commission for another week. Two weeks later returning to work, I'm still congested and coughing a bit. The timing was not ...

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  16. From J to K

    This is the first chance that I've had to write since we left for Japan. I have managed to keep internet contact while in Japan thanks to the b-mobile sim card. You can buy a six-month card in stores for about 20,000 yen, or you can order a ...

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  17. Are we having fun yet?

    Hello, this is my new blog where I will write about my life, including my transition from academics to the IT world. I expect that this will mostly be a documentation of the various tips and surprises that I learn every day as I focus on computing. It might be ...

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