drupal_install_fix_file in drupal-6.x/includes/install.inc

Attempt to fix file permissions.

drupal_install_mkdir in drupal-6.x/includes/install.inc

Create a directory with specified permissions.

drupal_verify_install_file in drupal-6.x/includes/install.inc

Verify the state of the specified file.

install_check_requirements in drupal-6.x/install.php

Check installation requirements and report any errors.

install_tasks in drupal-6.x/install.php

Tasks performed after the database is initialized.

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