7 calls to drupal_mkdir()

Archive_Tar::_dirCheck in modules/system/system.tar.inc
Check if a directory exists and create it (including parent dirs) if not.
Archive_Tar::_extractList in modules/system/system.tar.inc
drupal_install_mkdir in includes/install.inc
Create a directory with specified permissions.
FileTestCase::createDirectory in modules/simpletest/tests/file.test
Create a directory and assert it exists.
file_prepare_directory in includes/file.inc
Checks that the directory exists and is writable.
RetrieveFileTestCase::testFileRetrieving in modules/system/system.test
Invokes system_retrieve_file() in several scenarios.
system_check_directory in modules/system/system.module
Checks the existence of the directory specified in $form_element.