Archive for the ‘Cool Websites’ Category

Site5 Could Be Better

Friday, May 11th, 2007

A week ago I saw a posting on digg about how Dreamhost sucks. It got me thinking about the problems I’ve been having with my account with Site5. Let me say that at no point has my experience been anywhere as bad as the one described in that link.

My hosting plan is on a shared webserver. Here is an informative page about my machine, named iaso. It has four Intel 2.8Ghz Xeon processors, and four gigabytes of RAM. It runs Linux which is a solid server OS.

My big problem are periods when this very website is unresponsive. There are lots of other websites on the same computer. And by lots I mean on the order of 600 websites:


-bash-3.00$ cat /etc/passwd | grep -v nologin | wc -l
646

The number of users with logins is not a one to one list of websites served, but it’s probably a good estimate. All it takes is one of the 600 users with a bad webpage to clog up the machine.

Below is a plot of the load level for iaso over the course of 15 days last month. Without going into specifics, a load level of one means that there is one process needing a processor at any given moment. It will be many different processes, and that’s fine. Practically, a machine can stay responsive with up to about a load of three or four per processor. So, on a four processor machine like iaso, a load level of 10-15 is about the highest comfortable level.

What you see above are many occasions when iaso went well above load levels of 25. The highest peak was a load of 230. In my experience, once the load reaches 25 my website becomes more than slow: it doesn’t work anymore.

For comparison, below is a plot of the same thing on one of the nodes of the supercomputer I use, Datastar. This is the node where scientists do heavy-duty analysis on their datasets. For instance, I use this node to process my multi-gigabyte datasets using IDL. People also run Mathematica and other very computationally intensive tasks on this machine. It’s got 32 1.7Ghz Power4 processors and 256GB of RAM (what do you have on your workstation, huh?). It runs IBMs AIX 5.3. As you can see below, for the first four days, the load level stays below one process per processor. In the fifth day something happens and it goes above 60 for a while, before the machine gets rebooted and things return to normal.

The kind of processes that run on the two computers above are very different. However, the supercomputer is supposed to run big jobs and get beat on. A webserver isn’t. Anytime the webserver’s load goes above 25, it’s like the supercomputer’s load shooting to 256. At no time did the supercomputer shoot to 256, while the webserver goes above 25 many times. Of course, I’m comparing 15 days to 5 days in the two plots, but I think the differences are clear.

Site5 pays a third party to monitor their webservers, with results listed here. iaso has 99.8% uptime overall and 99.4% over the last month. This is bad enough that apparently I’m due a 5% credit on my next billing cycle. iaso isn’t even living up to Site5′s own service standards.

Every time I catch my website being slow, I contact Site5 tech support. I know that this is a common problem with shared hosting. I’m sure that Site5 is aware that these outages, and does what they can when they happen. But, when it does happen, it’s annoying. It shouldn’t happen in the first place. Sometime this summer, Site5 is changing their hosting solution which may help with these problems. We’ll see.

Yahoo! Mail support is a joke

Friday, April 13th, 2007

For some reason, lately when I go to Yahoo! Mail (mail.yahoo.com), occasionally instead of going to my inbox, I get a page of raw PHP. Here are the first few lines:


<?PHP
ini_set('display_errors', 0);
$data = yahoo_reg_login_setup();

if ( $data === FALSE )
{
exit();
}
else if ( ! isset( $data['DISPLAY_FORM'] ) )
{
error_log( "yahoo_reg_login_setup didn't set the DISPLAY_FORM field" );
header( "Location: http://login.yahoo.com/");
exit();
}

Here is the rest of the PHP code. It is obviously the PHP code that runs the base of Yahoo! Mail, which decides where to forward you: either to your inbox or to a login page. At any rate, there's no reason why Yahoo! Mail's servers should be sending me raw PHP.

When I get this page, if I hit 'refresh' I'll get the correct page, so things aren't totally broken. This slightly annoying, and it's obviously a problem with Yahoo! Mail's servers. My web browser is incapable of producing raw PHP code, much less with a Yahoo! Mail bug tracking number (see the full text).

Trying to be proactive, I sent this code to their help department. I also wrote "Please don't tell me it's my problem, as there is no way my browser can generate raw PHP." They wrote back telling me:

We understand that you're receiving a HTML error message in your account ... To help us troubleshoot and assess the issue, please take a screenshot of the entire page when the issue occurs next.

They then proceed with instructions on how to take screenshots in Windows. As a Mac OS X user, I found this help insulting and useless. I am no common Windows user, and they shouldn't assume I am. Furthermore, providing a screenshot is even less helpful than my original post, as the PHP code covers more than one contiguous window - I have to scroll to see all the PHP code. It's clear that either my message wasn't read, or the person reading it had no idea what I was saying and put in the most general pre-written reply they could find.

It says something about your company when this kind of 'help' is allowed. This person should have forwarded my message to someone who had a clue. They shouldn't have sent me anything, much less nonsense, when they no idea what I was writing about. Perhaps there is no conduit for this kind of thing between the Yahoo! Mail help staff and the actual programmers. If that's the case, it's a shame, and it's more evidence why GOOG is kicking YHOO's butt.

Shift/Tilt Photography

Wednesday, February 14th, 2007

I’ve recently discovered an obscure kind of photography, Shift/Tilt Photography. By using a lens that can shift laterally as well as tilt the lens elements, some very interesting effects can be achieved.

Shifting the lens laterally has the effect of keeping the edges of a vanishing object stay parallel. Buildings or door frames often suffer from this, here is an example of this vanishing effect. This happens because the film is not parallel to the plane the parallel vanishing lines define. Conveniently, wikipedia has some nice graphics showing that the goal in shifting the lens is to keep the image plane parallel to the object while also keeping the image on the film.

Another attractive ability of a shift/tilt lens is shown below. By tilting the lens, the sides of the shot can be brought out of focus in creative ways. There is a stripe of the photo which is in focus, and on each side the image is out of focus. Obviously, by rotating and shifting the lens, the location of the stripe can be moved on the image.

At first glance, this image above looks like it’s of a scale model. It is in fact not a model, rather it’s an aerial photograph (or from a tall building) using a shift/tilt lens. Here are more examples of this kind of photography from the same site. I’m fairly certain that these “the bitter* girls (place in your life)” (#) photos have been photoshopped to enhance the colors because they look just too saturated to be real. This has the effect of making things look more like a scale model with clean, unweathered paint. I think there’s also been some down-sampling because even where the photo is in focus, there’s not very much detail.

Through extensive searching online, it seems the widest variety of shift/tilt lenses are Russian-made. Here are a couple lenses which claim Minolta compatibility: MC 35 mm ($600) and MC 80 mm ($400) tilt/shift lenses. If any of you are feeling particularly generous, go ahead and buy me either lens. If you’re feeling especially generous, buy me both!

(#) The Japanese are weird. I can’t even imagine how that makes sense in Japanese. Perhaps it’s mangled English for the sake of mangled English.

Google Map Favorites

Wednesday, November 15th, 2006

I’m going post crazy tonight.

Here are some sites that use Google Maps in ways I find interesting.

Wikimapia

This site allows you to tag, with rectangles, any area of the earth at a wide range of scales. The image above shows the San Diego Velodrome which I tagged myself. This is a great time waster even if you’re only exploring.

Solar Eclipses

This site shows the path of all the total solar eclipses for the next thirty years. Clicking on the map brings up statistics for that spot on the earth. Start planning for the next one in the USA, in 2017!

Earth Sandwich

Ever wonder how to make an earth sandwich? First, put a piece of bread down where you are, and then quickly (before it gets eaten by your house mice), using this tool, put a piece of bread exactly 1/2 the way around the world. This tool tells me that my second piece of bread would get very soggy in the Indian Ocean.

Dodging the Rain

Saturday, October 14th, 2006

Five years ago I spent a summer in doing research at the University of Georgia. I’m from California, where between the months of May and September, it basically doesn’t rain. The hills turn brown and by early October wildfires start popping up all over the state, and really, the whole west. In Georgia in the summer, it rains. It rains quite often, in fact. There were thunderstorms nearly every afternoon.

It was in Georgia that I learned of the utility of the best weather site on the internet, wunderground.com. Their best feature, was, and still is, doppler radar that updates every six minutes when there’s rain. Five years ago all the other websites I searched updated the radar no more quickly than every half hour. In Georgia I would often log onto the website to see if I could dodge between thunderstorms and walk to the Physics building, or go for a bike ride. The radar was accurate and current enough to do this.

In the five years since the radar has just gotten better. Now you can zoom in, make animations, and use many other cool tools. Since I’m a paying customer (I believe it’s $10/year, and highly worth it) I get no advertisements and expanded radar tools.

Below is an example animation, fresh off the presses for today. It’s Saturday morning, a time when I usually go for a bike ride. In fact, the sun was out this morning when I woke up. But my trusty wunderground.com weather page told me that I’d better wait. I live just a bit north of the black cross with a circle around it, which you can see is about to get pummeled by some thick rain.

The other, more popular weather websites have gotten better in the last five years, too. However, I still think that wunderground.com is still the best by far.