Author Archives: jared

My impressions of Fedora 11

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Here's my take on installing Fedora 11, which was released June 9, 2009. I chose not to do an upgrade as I often do. Instead, I did backup, followed by a fresh install, preserving my /home partition, but wiping out the other partitions. Then I used meld to restore my configuration files in /etc -- such as ssh server keys, printer settings and file system mounts. I found that I had to use the kernel boot option nomodeset in order to avoid system lockups. Overall, I've been pleased with my Fedora 11 experience, despite the bumps.

Fedora 11 useful resources:

Pre-install:

  • cp -a /etc /home/backup/etc
  • cp -a /root /home/backup/etc
  • backup /home
  • booted the LiveCD to make sure it would detect my hardware and run

Install

  • I decided to preserve my partition layout, which isn't the default option upon fresh install
  • Didn't delete my /home partition.
  • Reformatted all other partitions, with "/" as ext4

Post-install:

  • Had to enable eth0 in NetworkManager, and make "enabled" the default.
  • yum install -y meld nautilus-actions nautilus-open-terminal vim-X11 zsh screen mc rdesktop
  • meld /home/backup/etc /etc
    • Restored /etc/ssh settings
    • Restored /etc/cups printer settings
    • Checked /etc/fstab differences
  • Installed NX Server

Pleasurable:

  • Bootup is very pleasant, and seems faster. 30 seconds boot. 17 seconds login. 14 second shutdown. This is on an AMD Athlon 2400 Mhz Sempron with an ATI video card.
  • Artwork is top notch (backgrounds on login screen and default wallpaper)

Pain points:

  • Unavailable extensions for Thunderbird 3.0 -- Enigmail
  • Unavailable extensions for Firefox 3.5 -- Aardvark -- QuickProxy
  • Computer locked up every few hours until I added nomodeset to my kernel settings in /etc/grub.conf.

Gnome Slideshow Screensaver Sanity, Take 2

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Last year, I wrote about how to achieve Gnome Slideshow Screensaver Sanity. I've recently upgraded to Fedora 11, and I noticed that GLSlideshow isn't installed by default (maybe it never was), and I wondered if I could alter the settings for gnome slideshow. By default, it uses pictures out of the $HOME/Pictures folder, and there's no way in the user interface to change that location, which can be frustrating. Here's how I worked around it. Note the use of the --location option, and that I changed my Name= setting.

  • cp /usr/share/applications/screensavers/personal-slideshow.desktop ~/.local/share/applications/my-slideshow.desktop
  • gedit ~/.local/share/applications/my-slideshow.desktop

[Desktop Entry]
Encoding=UTF-8
Name=Custom Photos
Exec=/usr/libexec/gnome-screensaver/slideshow --location=/home/images/Photos
TryExec=/usr/libexec/gnome-screensaver/slideshow
StartupNotify=false
Terminal=false
Type=Application
Categories=GNOME;Screensaver;
OnlyShowIn=GNOME;

Go into the screensaver preferences (System -> Preferences -> Screensaver), and select "Custom Photos". There's no way to customize the duration to display each photo, but at least I don't have to settle for Gnome's default location.

Backup that laptop!

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Recently, a relative called and said her laptop wouldn't boot. She wondered whether I could help. I asked if she had a backup. "No" was her answer.

I booted into linux (using Knoppix from a bootable CD) and attempted to back up her Windows account to an external USB hard drive. As I worked with the laptop, I discovered it was shutting itself off. On my second attempt, I managed to make a successful backup.

I tried running the system restore, but it would fail at random intervals. Next, I booted into the System Rescue CD and ran the memory test. It shut at random intervals during each memory test. I figured it couldn't be the hard drive that was at fault, but that the hard drive had probably gotten corrupted from the computer powering off suddenly.

My relative took her laptop to Geek Squad to see if they could diagnose the problem. They ran the system restore, and it succeeded. They didn't do any further troubleshooting. They charged her $50.00 without solving the root problem. It continued to shut off at random intervals.

A colleague of mine looked at the computer, and found that the heat sink on the CPU was clogged with dust. Most likely, the CPU was getting too hot and powering off. He removed the dust buildup, and from then on, the laptop seemed to work well. I was able to restore the files, and my relative was much happier.

And she bought an external USB hard drive to do future backups. Good thinking.

I use Mozy for automated, regular backups of my most important files. It's not a complete solution for my whole hard drive, but it's far better than nothing, and it only costs $5.00 a month. For linux, I need a similar solution. It turns out that there is one: spideroak. It runs on Windows, Mac and Linux. And it can synchronize files between several computers.

Wind farms — hot air?

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The media has a fascination with "alternative" and "renewable" energy, such as wind power. What if wind power is a bunch of hot air?

...if we wanted to go totally green, we'd have to carpet the [United Kingdom] with more windmills than exist in the whole world.

Undoubtedly, we need more power plants in the future. Utilizing windmills here and there sounds okay, but I don't want to see an entire countryside covered with them. I believe that nuclear power will be the most cost effective form of mass power, the cleanest and the safest in terms of the cost of human life -- compared to coal and hydro electric.

Every day physics

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This past weekend, our family visited Hill Aerospace Museum. While I was fascinated by the jets and both awed and disturbed by the cluster bombs and nukes, my children were most interested in the educational area where the flight simulators were located. They had building blocks, toy jets, flight suits, and hands-on experiments to demonstrate things like kinetic energy by smashing two steel balls together with a sheet of paper sandwiched in between to burn holes in it, resonance demonstrated with a notched stick propellor, and the structural strength of honeycomb, which is used in the building of aircraft.

I realized that I'm a novice on every day physics. I'm sure I studied resonance in my electronics and physics classes, but I don't remember it.

As for aircraft, I found it fascinating that faster is not always better -- the A-10 Thunderbolt II was built to fly slowly so it can support ground troops effectively, and it can still fly with half a wing and half a tail missing. Technology from 1950 is still in use today in the form of the B-52 Stratofortress, and will be for the next 30 years or more. So newer isn't necessarily better. I looked up the B-2 stealth bomber and found out that it's staggeringly expensive to build and operate. Coworkers mentioned the F-22 Raptor, and I was amazed to learn of its high bandwidth communication abilities. Apparently, many military pilots eat breakfast in the morning with their families, and arrive home in time for dinner because they fly remote controlled drone planes. When the pilot is removed from the cockpit, the plane can do things that would be impossible otherwise. It's amazing how much technology, expertise and money goes into building jets.

Article: Election Fraud in Kentucky

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Bruce Schneier summarizes the first documented case of election fraud using new electronic voting machines in his article Election Fraud in Kentucky:

Five Clay County officials, including the circuit court judge, the county clerk, and election officers were arrested Thursday after they were indicted on federal charges accusing them of using corrupt tactics to obtain political power and personal gain.

They used a low-tech social engineering trick to commit their crime.

Web Browser Security: Cracked in minutes

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There was a hacking contest at the CanSecWest 2009 security conference this past week, and it proved that web browsers still aren't secure. Here's the report:

Charlie Miller, in a repeat performance of last year, used a prepared exploit to crack the Safari web browser on a MacBook running the latest version of Mac OS X in a matter of seconds.

Following Miller, a 25 year old computer science student at the University of Oldenburg in Germany, who went by the name of 'Nils', used an exploit on Microsoft's Internet Explorer 8 circumventing the latest Data Execution Prevention (DEP) and Address Space Layout Randomisation (ASLR)... he then demonstrated an exploit for Safari and Mozilla's Firefox.

What does this mean for me and you? That if a well organized group or well funded organization wants to, they can and will hack your machine.

I think there's an extremely high likelihood that these hackers exploited a hole in JavaScript or Flash, not in the web browser's rendering of HTML itself. Running untrusted code from random sites never has been, and never will be, without security risk. That's why I use the NoScript Firefox extension. Unfortunately, it makes many sites confusing by reducing the "richness" of the web browsing experience, and can even break online shopping.

Is there a moral of the story here? Life is risky. Surfing the web is risky. By avoiding all risk, there is no opportunity, no life.

mwrc: Saturday evening Lightning Talks

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Binary Lottery code -- how he wrote the app.

Mhong - Event Machine. require 'eventmachine' module. EM.run { block } takes over your ruby, and nothing after that block will be run.

There's EM::PeriodicTimer and single-fire timers: EM.add_timer(2) { block } To use EM in your web-app, require 'thin' or spin up a new thread and use EM.run. EM.HttpRequest.new ... EM.system () ... { if status.exitstatus == 0 ... end }. Message queues, etc. Looks cool.

Dana Gray - regular expressions. "it's been two days since my last regular expression". She went over the basics of regular expression string matches. How to match word chars, positional anchors, capturing and non-capturing parenthesis, grouping, character classes. Don't fear regex, embrace regex.

Jake Cahoon from the Utah Valley Ruby Users Group. He used a slightly monkey-patched 'feedzirra' module to pull tweets using Ruby code. Finshed writing the code at 2 A.M. this morning. Now it pulls tweets and puts them into IRC. His code is on http://pastie.org

MerbCamp videos from last year are online. How to do Rack testing. with require 'rackbox/spec'. He wrote three apps that echo text in three different frameworks (sinatra, merb, rails), and showed the tests running against each. All in five minutes.

Sockets and Ruby. require 'socket'; client = TCPSocket.net('', 6789); client.write("Hello!"); ... server = TCPServer.new('127.0.0.1', 6789); client = server.accept; client.recv(500);

MongoDB - a document oriented data store. Supports native Ruby objects. Has full index support. Uses memory mapped files for speed. Has a file storage API. Will support sharding soon. Best use cases: Most web apps, caching (memcachedb + indexes), when you need high scaleability. Worst case use cases: Transactional systems, data warehouses. Why should you use it? Fast! No migrations, ever. Replaces memcached & tokyo. Has great Ruby support, and it's not mySQL. http://mongodb.org

It's easy to contribute RSpecs to Rubiniess. One presenter showed how.

Brian Marick: How to learn from the screw-ups of the past. He's been involved in three movements in computer programming in the past 20 years. First, it was lisp, which was going to take over the world, but died when it failed in the commercial world. Second was ???, and third is Ruby. He thinks "agile" is in trouble like lisp was in trouble. Agile was founded by people who like to program. The key thing that was missing from agile is solidarity of action. He ran out of time to complete his thoughts.

Coby R. announced the LA Ruby Conf - April 4th, 2009

Justin Graham showed a working example of Adhearsion (the Ruby telephone framework for Asterik).

Pat Eyler - Ruby Brigades. You should participate in your local Ruby Brigade so that you can strengthen the community. It's a chance to grow and learn. The best way to learn is to teach others. Simply show up. It's discouraging when someone organizes a group and no one shows up. Get on the mailing list. Don't just subscribe. Ask questions. Answer questions. Be involved. Give a lightning talk at the meeting.

There are two types of meetings: Ones that are a launchpad, and ones that are a destination. Don't let your meetings become a destination. Make the world a better place.