Archive for December 2010

Elance “Skills Assessment” Tests — HA!

Sometime in 2000 or 2001, I was asked to create a skills assessment for senior-level relational database management systems experts for a very young Brainbench. I was not alone: the company selected a total of four of us, all given the assignment of coming up with forty-five multiple-choice problems related to the general concepts of RDBMS. It took me about two days to complete the task, and a few weeks later, when the test went into a public beta, folks could take the test and vote on the quality of the questions. The results of the votes were not shown to the public, and we (the consultants who created the questions) were not privy to the voting statistics either. Several weeks after that, the test became official, and I aced it: every one of the forty-five pages were from my packet.

Despite being rather proud of myself for a relatively small accomplishment, I was actually really surprised; the quality of the submissions from the other consultants was all – in my opinion – very, very good. In fact, I felt more as though some of my own paled in comparison. It seemed that all of the other submissions were by folks who really understood the topic thoroughly, and were masters in their field. In fact, I did later learn that I was the only one of the four hired who did not have a computer science degree. Talk about humbling.

Today I decided to take a few skills assessment tests on Elance – a leading online freelance marketplace – on a variety of technical subjects. Included in the ones I took were tests to evaluate one’s comprehension of Linux and Amazon Web Services.

I was disgusted.

The grammar was horrible. The content was filled with fluff and trash. The questions weren’t representative of someone’s working knowledge on the subject — in fact, some even took text from “About Us” sections that described the company, not the service provided. And in the Linux test specifically, there were cases of areas where multiple answers were correct, but only one could be chosen; other times where no answer was technically correct, but a choice had to be selected. The most appalling of it all: questions on obscure, unnecessary things like “Which of the following software packages is used to create a closed-circuit television system?” I had to look that one up after the fact. I didn’t take a test on how to set up a video system, I took a test on Linux skills. I highly doubt the MSCE or MVP tests ask for the steps of motion tweening in Flash.

It was quite obvious that the tests were created by folks with limited knowledge on the subject matter. In fact, it was probably completed – at least in majority – by the lowest bidder, who may very well have been a non-native-English administrative assistant. Hell, nowadays, anyone with Internet access thinks they have the skills and marketability to work as a professional freelancer. Some do…. most – and I really mean MOST – do not. These so-called “skills assessment” tests were proof-positive of that; they’re a joke, and folks serious about testing the skills of others would be ashamed to have them as the representation of their own knowledge on a given subject.

Granted, I can’t speak for all of the tests. There are many available, and on a wide variety of topics. I’m sure that some are much better than others, and that some of those may actually be very good at gauging an individual’s skill on the matter. Now they just need to try to get that same quality across the board.

Because if I can take a test on something of which I admittedly have almost zero knowledge, be more confused by the spelling and sentence structure of almost every single question and option, score a barely-passing 65%, yet still be in the “Top 10%” of all test-takers, something must be wrong.

(Finally) Announcing the Public Release of FileConv for PHP

Almost exactly two years ago, on New Year’s Day, 2009, I sent an email describing a new PHP extension I’d finished, and was interested in submitting to the PECL repository. The package, entitled FileConv, would natively handle file conversion for line endings, back and forth, between *NIX (LF: \n) and DOS (CRLF: \r\n). At that time, Ilia Alshanetsky recommended that I also add Mac conversion (CR: \r). Legacy MacOS, that is, prior to becoming a sort of ClosedBSD, if you will.

Somehow, as often happens in our busy lives, I forgot to follow through with submitting it to the PECL repo. Last night I was using one of the functions and found a datestamp bug, where – in certain situations – it would give the converted file a date approximately 430,000 years in the future. That’s actually almost 253-times the estimated duration for the complete decomposition of a modern PC, which is figured to be a paltry 1,700 years. That said, once I patched the file and recompiled, I was reminded of my discontinued effort to release the code to the public as an open source package. Well, time to change that, I suppose.

So today, you can download the FileConv extension right here:
FileConv-2.2.6.tar.bz2 (7,073 bytes)
FileConv-2.2.6.tar.gz (6,636 bytes)
FileConv-2.2.6.zip (10,531 bytes)

MD5 Hashes:
– d6200f0693ae63f9cc3bb04083345816 FileConv-2.2.6.tar.bz2
– c2b0db478628e0a4e2ce66fb06d19593 FileConv-2.2.6.tar.gz
– b3ff103424e4be36151a1c5f9cadd58d FileConv-2.2.6.zip

SHA1 Hashes:
– 0521fdeaa8bfb250c8c50bc133b355872fa70cad FileConv-2.2.6.tar.bz2
– 08e2c361fc41f925d0b4aa3a0bbdd7e0884b24d6 FileConv-2.2.6.tar.gz
– 9eb9355555dd8e6e6b6b7f3dc7464c7a6107b187 FileConv-2.2.6.zip

Keep in mind: this has only been tested on Linux (CentOS, Mandriva, and Ubuntu), as I have neither the ability nor desire to play on Windows (but feel free to try it). In a future release, the code will be compacted more, as well; right now, every conversion function has its own function within the source. This isn’t necessary: it could be a single master function with a simple switch for one small section of the code. I’ll get to that another day, when I have some time to hack it up again.

This distribution comes with a very simple automated installer for now. If/when it moves to PECL, that will be phased out, of course, as PECL will handle that itself. If you have root/sudo access on the box, you can just run ./install.sh from the package directory and follow the instructions from there. Manual installation instructions are included as well.

This package provides functions that somehow never made it into the PHP core: dos2unix(), unix2dos(), mac2unix(), mac2dos(), unix2mac(), and dos2mac(). It does not, however, do any checking or validation prior to conversion. If you decide to use this library, I’d highly recommend employing some basic checking in your code. Something like this should be used at a minimum:

<?php
function get_info($filename) {
  if (!function_exists('version_compare') || version_compare(phpversion(),'5.3.0','<')) {
    return trim(`file {$filename}`);
  } else {
    $finfo = finfo_open();
    $format = finfo_file($finfo, $filename);
    finfo_close($finfo);
    return $format;
  }
}

if (strpos(strtolower(get_info($filename)),' crlf line')) {
    // File is DOS (\r\n)
} elseif (strpos(strtolower(get_info($filename)),' cr line')) {
    // File is legacy Mac (\r)
} else {
    // File is *NIX (\n)
}
?>

NOTE: this does not ensure that it is a text file. You are strongly advised to address that as well. The included test.php file has a line that checks to see if the file is binary or text, so feel free to plagiarize that — or, better yet, build a better mousetrap.

If you come across any bugs/issues/whatever, let me know.

Skype and Google Earth Causes X To Crash On Ubuntu 10.10

[UPDATED 19-JAN-2010 – Thanks to Drew (in the comments) for bringing up the fact that this is only for 64-bit versions of Ubuntu. The filenames would indicate that, but no sense wasting your time if you’re looking for a 32-bit solution. Well, at least not yet. I may do a 32-bit build if there’s a need, but it seems as though the official repos may now have the patched versions. Have you gotten an official solution that resolved the issues? Feel free to let me know in the comments.]

After months of dealing with the mouse getting stuck between monitors, blinking like crazy and freezing all but remote SSH administration of my Ubuntu 10.04 (Lucid) desktop with triple-head monitor setup, I gave up and upgraded to 10.10 (Maverick) in hopes that it would fix the issues. I didn’t know if it did or not, because it introduced new errors. Worst of all: any time I would launch Skype, the screens would go black and X would crash in a segfault and restart. The same was true of Google Earth and of at least all Qt applications on the desktop. It took a good thirty-six hours before I traced everything back and came up with a solution. So now I’m running 10.10, which not only has a couple of minor improvements, but also seems to have finally fixed the mouse-locking issue. Hooray!

My issue turned out to be rooted in an issue with Xinerama on X with multiple monitors on an x86_64 box running the final stable of Ubuntu 10.10 (Maverick). If you have the same issues (Skype crashes X), try downloading the following file (routed through my company’s URL service so that it’s easier to share):

http://links.parasane.net/fvsq

The filename is xorg_crash_fix_debs_and_NVIDIA_driver_x86_64.tar.bz2, with the following hashes:

MD5: fe2fa5684a0f051d552bd7d0b4ee6f6a
SHA1: 0edea79d4832ce31954e29991405a67403732639

Applying it is simple (provided you have experience in knowing how to resolve your own dependencies, if any are missing). If you’d like to nip it in the bud before getting started, here’s an all-inclusive list of all packages of which I’m aware that you should have installed or which may be needed to finish this process without errors (feel free to pick and choose on your own, if you’re more comfortable doing a minimalist installation):

sudo apt-get install debhelper quilt bison flex xutils-dev x11proto-bigreqs-dev x11proto-composite-dev x11proto-damage-dev x11proto-xinerama-dev x11proto-randr-dev x11proto-record-dev x11proto-render-dev x11proto-resource-dev x11proto-scrnsaver-dev x11proto-video-dev x11proto-xcmisc-dev x11proto-xf86bigfont-dev x11proto-xf86dga-dev x11proto-xf86vidmode-dev x11proto-dri2-dev libxfont-dev libxkbfile-dev libpixman-1-dev libpciaccess-dev libgcrypt-dev nettle-dev libudev-dev libselinux1-dev x11proto-xf86dri-dev x11proto-gl-dev libxmuu-dev libxrender-dev libxi-dev x11proto-dmx-dev libdmx-dev libxpm-dev libxaw7-dev libxmu-dev libxtst-dev libxres-dev libxv-dev libxinerama-dev devscripts build-dep xserver-xorg-core

The steps to installing the fixed binaries are:

  • Drop to an alternative TTY prompt: Press CTRL+ALT+F1
  • Download the package file: wget http://links.parasane.net/fvsq -O xorg_crash_fix_debs_and_NVIDIA_driver_x86_64.tar.bz2
  • Uninstall your current NVIDIA drivers: sudo nvidia-uninstall
  • Decompress the file linked above: tar -xjvf xorg_crash_fix_debs_and_NVIDIA_driver_x86_64.tar.bz2
  • Change to the newly-created directory: cd xorg_crash_fix_debs_and_NVIDIA_driver_x86_64/
  • Install the core and common packages: sudo dpkg -i xserver-xorg-core_1.9.0-0ubuntu7_amd64.deb xserver-common_1.9.0-0ubuntu7_all.deb xvfb_1.9.0-0ubuntu7_amd64.deb
  • Set execution permissions on the included NVIDIA driver: chmod 0755 ./NVIDIA-Linux-x86_64-260.19.21.run
  • Execute the new NVIDIA driver: sudo ./NVIDIA-Linux-x86_64-260.19.21.run
  • Reboot the system: sudo shutdown -r now

You should now have a fully-working X system again. And if you upgraded because of the mouse-hang issues, you should be in good shape there, too!

NOTE: It should be VERY obvious, but this comes with absolutely no warranty or guarantee whatsoever, and you’re completely responsible for any issues that arise, directly and/or indirectly, from usage of these packages or instructions, et cetera. You know the drill by now, I’m sure.