you're running ldap on windows. Why?

Although I can guess several reasons, I would have liked the article to follow it's definition of a directory with a sentence or two explaining why it's better than accessing a database directly.

Can anyone answer this?

Probably to illustrate the example of how to connect to LDAP through PHP.

It doesn't matter what LDAP is running on as far as PHP is concerned.

I agree though, in most situations you'll be connecting to a groupware LDAP server or something which may be running on Linux. But could easily be running on Windows in the form of Exchange.

The first sentence of this article confuses me.

"A directory service is an application that lets you store, retrieve and modify information about network-attached resources such as users."

Personally, I think of users as the leeches that USE resources, not resources themselves. Now, it's time to go read the rest of the article.

Windows is used on 90% of desktops.

If a directory is stored directly in a dataabse the directory information would have to be mapped to multiple databases. Also the directory service provides attributes, which facilitiate update and search of directory information. The alternative is using the WHERE cluases in SQL statements to update and search.

Please also refer "LDAP vs relational database", which is for OpenDS, but most of the advantages also apply to OpenLDAP. Both OpenDS and OpenLDAP directory servers are based on the embedded Berkeley DB database.

http://blogs.sun.com/treydrake/entry/ldap_vs_relational_database

Please also refer

http://blogs.sun.com/treydrake/entry/ldap_vs_relational_database_part

http://www.linuxtopia.org/online_books//network_administration_guides/ldap_administration/intro_LDAP_vs_RDBMS.html

Also DBAs would be required to administer the database.