Archive for November, 2007

When autocomplete goes bad

Monday, November 5th, 2007

In common with a lot of AJAX-based sites, ZoomIn makes a lot of use of autocompletion, specifically to make it easier and more reliable to enter addresses. But thanks to this article from Gizmodo, we can see some of the hilarious questions that come up when autocomplete kicks in too early: Ask.com helpfully starts completing a phrase such as “is it legal to” with some bizarre and sometimes hilarious queries from other users.

But my favourite is an example that shows the touching faith that some people have in the Internet. Apparently it will answer questions that have stumped philosophers since the dawn of humanity:

Theology via Ask.com

Varnish – Squid's heir apparent?

Monday, November 5th, 2007

We’re in the process of rebuilding our server infrastructure. We’re shifting from debian sarge with postgres 7.4 to Ubuntu 7 and postgres 8. We currently investigate the stability and scalability of various rails stacks. Also we’re looking at different solutions of handling high volume static content delivery ie. delivery of our map tiles. (This could apply to any static content like thumbnails) During our research into reverse proxy alternatives, Paul Gold put me onto varnish.

Varnish is written from the ground up to be a high performance caching reverse proxy. The author built it due to his frustration at squid and he provides a detailed analysis of why squid sucks. In his own words…

Varnish is written from the ground up to be a high performance caching reverse proxy. Squid is a forward proxy that can be configured as a reverse proxy. Besides – Squid is rather old and designed like computer programs where supposed to be designed in 1980.

– Poul-Henning Kamp, Varnish architect and coder.

I’ve done a little bit of testing against lighttpd 1.4, apache 2.2, vs varnish with some surprising results.

My test involved using apache bench (ab) in a brute force test of fetching a 1k, 5k, 10k and 20k image file. I tested against 50,100, 200 concurrent users. (eg. ab -n 20000 -c 100 http://test/5kimage.jpg ) I tested against a default installation of apache 2.2 and lighttpd 1.4.12.

Here are the results:

File Size Concurrent Users Apache 2.2(reqs/ sec) Lighttpd 1.4.12(reqs/ sec) Varnish 1.1.1(reqs/ sec)

1k

50

3792

2050

5386

1k

100

3949

2135

5471

1k

200

3973

1946

5228

5k

50

2087*

1655

2075*

5k

100

2051*

1764

2076*

5k

200

2006*

1764

2062

10k

50

1063*

1065*

1065*

10k

100

1059*

1064*

1060*

10k

200

1056*

1056*

1055*

20k

50

571*

560*

570*

20k

100

569*

560*

564*

20k

200

566*

562*

566*



* = Denotes network throughput was approaching  10.93Mb / sec . The size of the network connection was effectively putting a cap on the throughput.

A couple things to note from the testing. First,  Apache forks a lot of processes, while lighttpd and varnish fork threads.Also, the CPU seemed to be under less load using lighttpd and varnish compared to apache.

From the results, Varnish excels at caching small files, and as fast as the other servers at higher file sizes. I want to do a bit more testing against varnish. For my next set of testing, I’ll test the webservers against 100 random images and post the results.

Forget about Full Code Press, what about Hell's code !?!

Monday, November 5th, 2007

hells-kitchen.jpg


Here’s something for Monday morning…

37 signals have written a post about what Gordan Ramsay can teach software developers. Its a great post, with some good analogies. That made me think….

Forget Y-Combinator, forget Full Code Press, what about Hell’s Code ?!? Get developers to spend a number weeks going through a number coding challenges and eliminations until they win full funding for a start-up for a year ? Clients would wait around until the developers complete their prototypes, beta apps and full applications and give them a rating….

I thought it would be fun to imagine what Gordon Ramsay would say and do if he ran Hell’s Code ???

What would he yell at ???

  • Developers who forgot to install a patch or module – (Forgot to add an ingredient)
  • The application didn’t run (The dish is cold !)
  • Didn’t test their code (Forgot to test the meat)
  • Didn’t use CSS (Forgot to season the dish)

I can imagine Gordon Ramsay, if he found something wrong, he’d delete the code and tell them to start again. And if the developers made too many mistakes, he shutdown the coding and send all the clients home!

What else would Gordon Ramsay do ????

FYI: How to fix a invisible folders on Windows USB disk, but visible on Mac OSX

Thursday, November 1st, 2007

Here’s a fix to a problem I had with a using an usb drive on both Mac and Windows.

Problem: A directory of files was missing from a USB drive. (NTFS formatted USB drive). But, when I browsed the disk on Mac, the directory and files were visible.

Looking at the disk properties (ie. disk space used on the drive), it showed that the files were still there. It was really strange, and a lot of googling couldn’t find the answer.

Solution: Use the dos command chkdsk -f to fix the errors on the disk. The USB disk must have got corrupted when switch between machines.

Thanks to Milton for suggesting the fix. The problem was exsaserbated because it happen which I was migrating from Windows to Mac. 🙂

Across from the dark side…

Thursday, November 1st, 2007

I switch to a mac about 6 weeks, ago. Here’s my thoughts about the pro’s and cons of my experience.

Pro’s

  • Fast boot / reboot times – No more waiting 2-3 minutes to boot up!
  • Better memory management – I run my firefox with 15 open tabs and  zillon of  applications and it handles it fine. (Memory usage for dashboard is a little scary)
  • Front row – Brilliant when traveling
  • iPhoto – nice integration with front row
  • Keynote is awesome. Runs rings around powerpoint
  • Parallels is great. Boots faster than my old laptop !

Con’s

  • No being able to tab into application windows. eg If I am writing an email, if I tab away I can’t tab back to the open email.
  • File copying. Copying files deletes directories then copies files rather than replacing the files. Got bitten by this big time.
  • iPhoto not having real picture resizing built in
  • Finder not having a thumbnail browse..

I’m really glad that I have switched. I’ll wait a bit before I install Leopard.


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