34. How to enable clean urls in drupal ?

The standard Drupal installation contains a sample .htaccess file which supports clean URLs. It is easy to miss copying this file, because of the leading "dot". So before trying to enable Clean URLs, make sure this file exists in your Drupal installation.

Drupal 6.x
In Drupal 6, the installer tests for compatibility with Clean URLs as a part of the installation process.
Drupal 5.x
Goto the administer >> site configuration >> clean urls section of the administrative interface.
Clean urls can be enabled by following the above two options in respective versions of drupal website.

31. What are systems requirements for drupal installation ?

Disk space

A minimum installation requires 15 Megabytes. 60 MB is needed for a website with many contributed modules and themes installed. Keep in mind you need much more for the database, files uploaded by the users, media, backups and other files.

Web server

Apache, Nginx, or Microsoft IIS
More details about web server requirements.

Database

Drupal 6: MySQL 4.1 or higher, PostgreSQL 7.1,
Drupal 7: MySQL 5.0.15 or higher with PDO, PostgreSQL 8.3 or higher with PDO, SQLite 3.3.7 or higher
Microsoft SQL Server and Oracle are supported by additional modules.
More details about database requirements.

PHP

Drupal 6: PHP 5.2.x only. Warning: support for PHP 4.x has been dropped. PHP 5.3 and later may produce errors or unexpected behaviour.
Drupal 7: PHP 5.2.5 or higher (5.3 recommended).
Drupal 8: PHP 5.4 or higher.
More details about PHP requirements.

updated on 19.04.2014.