Entries by David Rolston

I gave a talk on the use of Xen for web developers at Lampsig. It took me a while to get my notes transcribed, but here at last they are. This prescription has been used by me to install Xen successfully on a Fedora core 4 box, Centos 4.3 and 4.4 boxes, and should probably work on RHEL, assuming you can figure out how to get the packages you need.

I cover use of file backed file systems, and how to mount and edit them, as well as expanding a file based filesystem.

I have run gentoo and Centos guests I got from jailtime.org and have found them to be very stable. I even was able to use this on a 64 bit server, although I did have to build my own guest. Many people who have had trouble getting Xen to work reliably when using the packaged (rpm) versions of Xen may find this prescription fixes their problems.

Xen 3.0 Centos How-to

I recently had need to add XWindows to a Centos 4.x install that didn't have X or Gnome. I was doing this under VMware which added slightly to the degree of difficulty. As it turns out, using Yum makes this a very easy process, although you probably end up with some bloated packageware.



Pay close attention to the capitalization -- Yum is picky. "Gnome desktop environment" won't work, for example.

I have a small phpBB2 forum attached to this site, that I used briefly to support some of my side projects. phpBB has had a checkered past in terms of security, having been the victim of many exploits. To be fair that's one of the costs of having been one of the first and most widely successful php based community projects. The number of phpBB deployments is staggering even to this day. With so many forums out there, spammers quickly figured out that if they could write a bot to create an account and auto post messages, they'd be able to spread their spam messages far and wide. I was getting so much spam, I ultimately disabled the ability of people to authenticate their own accounts, and despite this change, still see as many as ten new signups for the forum every day. Who would bother to sign up for an account they can't use? There had to be a way of determining the bots from the humans who wanted to post to my forum.

CAPTCHA, as the conventional wisdom of the day was concerned, would provide a useful deterrent to this annoyance -- bots arent' smart enough to decipher the captcha images and extract the right combination of numbers and letters depicted in the image, and type them back to into the form in order to unlock the account. Without the account, the spammers couldn't have their bots post their spam messages. While phpBB introduced a CAPTCHA capability relatively late in the game, it is now something you get out of the box, and there is at least one mod that improves on the quality of the CAPTCHA image, which is to say, makes it harder to read.

The problem is that CAPTCHA's are there to defeat dumb machines, but not dumb humans. And as the old saying goes, there's a sucker born every minute who is more than happy to help your local spammer defeat the CAPTCHA image on your site. How might you ask? Well, the scam works something like this: John Q. Sucker visits some site that informs him he's getting something for free -- it could be a free ipod, porn, or an xbox 360. All that is important is that this person believes they will be getting access to this free stuff once they register.

They visit the spammer's site, and are presented a CAPTCHA image in order to register, only, this image didn't come directly from the spammer's site -- it came from YOURS. The spammer writes a simple bot that goes to your site and hits the registration page. It takes the CAPTCHA image your site provided, and presents it to John Q. Sucker on the spammer's site.

Continue reading "CAPTCHA busting -- A sucker born every minute" »

I woke up the morning of tuesday August 15th, 2006 at 6:45am, and after looking around for a minute, realized that Scrappy wasn't on his dog bed. As I had an 9am meeting that day, I went upstairs to find him, and discovered him on his side, having passed away probably in the early morning hours. He lived to be twelve years old, and his death was a great surprise and shock to us. Although he hadn't been eating well, and was on some medication, we never suspected that anything was seriously wrong with him. He had been acting fairly normally and was as animated as ever especially when any "people" food was involved. He'd been up to all his usual tricks, jumping on the couch, and trying to steal things off Niamh's plate whenever she might put it down for a minute.

We decided to have a laboratory do a post mortem exam, and later that day, they called to inform us that Scrappy had a number of cancerous growths on his liver and pancreas. One of them had ruptured, and according to the lab, although it was a sudden upredictable event, it nevertheless was inevitable. They assured us that there was nothing we or they could have done, and that he wouldn't have suffered much.

We bought Scrappy from a Pomeranian breeder located in Riverside county, which is east of Los Angeles. We'd recently moved to an apartment in West Hollywood, and wanted a companion to keep Gizmo company during the days while we were at work. Tracy had spoken to a breeder over the phone and negotiated a deal for a Pomeranian puppy who they hadn't been able to sell and was now too big. My recollection is that he was already five or six months old, but perhaps a bit younger. It was a friday after work, and we jumped into Tracy's old VW rabbit, and headed out on what would turn out to be a two hour soujourn which included our getting lost, driving up and down lightless suburban streets, and giving serious consideration to turning around and heading home. At the end of a dead end street, I finally pullled the car over and got out. The address seemed to be in the vacinity of the one we were searching for, but we were expecting a ranch or warehouse rather than the rows of tract houses. We couldn't find a street number. Then I picked up the faint sound of dogs yapping. I followed it to the garage of a house and rang the doorbell. An elderly woman answered the door holding a tiny white pom in her hands.

Continue reading "Scrappy" »

Recently I was driving home one evening and a local radio talk show here in Los Angeles was bemoaning the disappearance of the "situation comedy" from the lineups of the major US TV networks. Most adults remember the golden age of the TV sitcom, and classics like Taxi, Cheers, Roseanne, Cosby, Family Ties, Friends, Frasier and Seinfeld. With seminal 90's sitcoms like "That 70's show", "Friends", "Will and Grace" and "Everybody loves Raymond" calling it quits, and with the failure of critic favorite "Arrested Development", the number of sitcoms on the air and the ratings of the few that are left, are at a historic nadir.

Anyone who doesn't see the connection between an increase in internet use and the decrease in television viewership is in serious denial. A recent Jupiter Research report found that people who have an Internet connection spend as much time online as they do watching TV. This trend, when considered along with the rapid adoption of Digital video recorders like Tivo, signals the death knell of the golden age of network television -- and an end to the era when consumers would revolve their weekly schedules around their favorite "must see" shows.

Which brings me to consideration of "The funniest show (not) on TV". It's a situation comedy of sorts, although its not really a series at all. It's on a network which isn't really a network. It has no budget, no production company, no promotion, sponsors, and during its entire one year run, faced cancellation on a monthly basis, based on the direct input of those who had watched its most recent episode. Could this be the future of TV?

Continue reading "The funniest show (not) on TV" »