Directory slash redirects? Does this still happen?

I was reading an article referenced by Jeff Atwood about Yahoo's "Best Practices" for speeding up a website, and I noticed this little gem:

One of the most wasteful redirects happens frequently and web developers are generally not aware of it. It occurs when a trailing slash (/) 开发者_如何学Cis missing from a URL that should otherwise have one. For example, going to http://astrology.yahoo.com/astrology results in a 301 response containing a redirect to http://astrology.yahoo.com/astrology/ (notice the added trailing slash). This is fixed in Apache by using Alias or mod_rewrite, or the DirectorySlash directive if you're using Apache handlers.

Does this still happen? The article is pretty old, as the web goes. I think I've been doing this for years. I don't think I've noticed this happening lately, but then again I've never really looked. Is this an Apache thing? Does IIS 7 do this?

I'm scared. Hold me.

Try it!

Here are some truncated requests run from the terminal.

curl -I  http://astrology.yahoo.com/astrology

HTTP/1.0 301 Moved Permanently
Date: Tue, 21 Jun 2011 13:24:24 GMT
Location: http://shine.yahoo.com/astrology/


curl -I http://wordpress.org/extend

HTTP/1.0 301 Moved Permanently
Server: nginx
Date: Tue, 21 Jun 2011 13:26:17 GMT
Location: http://wordpress.org/extend/

Though it seems that IIS does it the other way:

curl -I http://www.iis.net/overview

HTTP/1.0 200 OK
Server: Microsoft-IIS/7.0

curl -I http://www.iis.net/overview/

HTTP/1.0 301 Moved Permanently
Location: http://www.iis.net/overview

Guess it depends how you have it configured, but it's definitely something to optimise.