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  • Introduction

    Often, when you build a website, you want columns.

    Common designs include

  • I've got those 3 button mice from SGI as I was working with Indy's and O2's. I also have keyboards. Those are real good quality!

    Yesterday, I tried to right click and somehow, nothing happened. At first I thought maybe it was X going banana, but trying again and restarting did not change anything. I reset my KVM too, just in case. Still nothing.

  • I have noticed that quite a few people were trying to create UDP communication and I thought that proposing my class could help them. This is very basic as it does not define anything such as the size of a packet or any protocol to ensure arrival of the packets. However, it can be useful if you want to send a signal from one process to another, which is exactly how I use this implementation.

    This code is part of the Snap! C++ implementation. It can be found in the corresponding SourceForge.net repository.

    Header file:

    // UDP Client Server -- send/receive UDP packets
    // Copyright (C) 2013 ...
  • Ada variables are complex objects. When developing a compiler, you must definitively take that in account. You have several sides to your variables: one you need to be able to handle dynamic variables since the compiler will have to be capable of doing all the operations on all the constant variables just as if you were executing your program and it has to handle all the tests necessary to ensure integrity.

    So... we need a library that can handle integers, a library to handle floating points, a library to handle arrays, etc.

  • Once in a while I want to add my user to a group and then right away make use of that group.

    Unfortunately, in general Unix kind of forces you to re-log in for the new group to be attached to your account.

    However, a command has been added, a while back, to do just that on the fly. Not something you would want to use in a script, but at least, it works for me when doing a few things here and there.

    In my case, I wanted to run QEMU, which I hadn't done in a while, and the system told me that it could not open the KVM, the error: kvm permission denied.

    The problem was that I was not part ...

  • I just switched my websites from one server to another and noticed that on my main company site (http://www.m2osw.com) I would get a # at the end of the URL. Automatically added somehow. Thinking that could be a bad guy I checked the code and could not really see anything.

    Hitting "Back" once, I noticed that the # would be transformed to #atssh-digg. I don't have anything specific about digg on that page except the AddThis button. That adds Digg among some 150 different systems where you can share my pages.

  • Managing your own Drupal Download Site

    The other day, I was thinking, it would be nice if I could find the way to manage my own download site so people who use my modules that I do not provide directly on https://www.drupal.org would still show as expected (i.e. Green in the update window).

    I found this page about it: https://www.drupal.org/node/210984

    This is done by creating a service in your Drupal environment. You should use the ready made script named:

    project-release-serve-history.php

    which you can find in the D6 version of the Drupal project named Project. Being very ...

  • If you are running a webserver, you should use a webserver firewall. This prevents many attacks from being perpetrated on to your servers without the need to make your own applications more complex than necessary.

    The idea is very simple, if you have a few people who can edit your data from the Internet and those have a static IP address, you can check that the editor pages are only accessible to those IP addresses. Any other access can simply be blocked.

    [toc hidden:1]
  • I have been wondering, for a while, why is it that I get errors about DEFLATE no being known.

      [Sun Apr 11 22:41:23 2010] [error] an unknown filter was not added: DEFLATE
      [Sun Apr 11 22:48:54 2010] [error] an unknown filter was not added: DEFLATE
      [Sun Apr 11 22:50:23 2010] [error] an unknown filter was not added: DEFLATE
    

    I should have thought of it, the deflate module was not installed. That was it, but oh well... 8-)

    To tweak your Apache setup, use the following two lines:

      sudo a2enmod deflate
      sudo /etc/init.d/apache2 force-reload
    

    And you'll get rid of those ...

  • I installed a website on a brand install installation of Ubuntu 14.04 (opposed to an upgrade from earlier versions) and the same website would not start...

    Apache2 would give me the following error:

    client denied by server configuration

    which did not seem to tell me anything... I search for the error and the first page that popped up was a page by Apache2 and they said to add the deny/allow trick. I tried that and it did not help.

        <Directory /my/special/directory>
            Order allow,deny
            Allow from all
        </Directory>

    Search further, I found an answer on ...

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  • number

    All software make use of numbers. Everything is a number. The most basic number in a computer is 0 or 1. This is called a bit. These are represented with electricity. Although in most cases we see it as 0 - Ground and 1 - Voltage (i.e. 1 volt), the bit representation in software and in hardware may be interpreted either way (i.e. a 0 could mean that the voltage is 1V and not 0V.)

    Combining these zeroes and ones we offer end users to handle much larger numbers. With 8 bits, you can have numbers from 0 to 255 (unsigned) or -128 to +127 (signed.) Now a day, computers can handle a much larger number of bits in one cycle. Most processors use 64 bits but they can calculate numbers on 128, 256, and for some 1024 bits at once. Also with parallelism, the size can be viewed as even larger (i.e. handling a 64 bit number in 1,536 threads like on my old nVidra Quadro 600 is equivalent to one large number of 98,304 bits! That would be 2 power 98,304 possibilitie or about 2.8359e+29592 in decimal.)

    Integers are easy to handle. Although when working on math problems you generally see the set of avaialble numbers as equivalent to N although mathematicians know that computers can really only handle a limited set of numbers. For example, on a 64 bit computer, the usual range is -9223372036854775808 to 9223372036854775807, This is generally enough although at times some equations have to be reworked to avoid really large or small intermediate numbers that work fine in math equations, but not so well on computers.

    Now, math also includes other sets of numbers such as D, R, and C. Computers do not offer any way to represent numbers in R or C but they can offer D to some extend. These numbers are called floating point numbers because we do math using an exponent. The exponent makes the decimal point "float" in any location as the number used for the exponent offers. Using a 64 bit floating point, you can have positive and negative numbers with precision varing betwee 10-308 and 10+308. This includes a positive zero (+0) and a negative zero (-0), which is import in a few cases (although +0 = -0 is true, you can get the sign of a number and distinguish both zeroes). Note that at first decimal numbers were going to also have a positive and negative zero, but it was instead decided to have one more negative number (remember, with 8 bits we have signed numbers from -128 to +127, this is because in the positive numbers we have a 0 which we don't have in the negative numbers.)

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