- Patch #347959 by sun, Damien Tournoud, justinrandell, scor, chx: modules_installed() was broken during testing.

#399642 follow-up by JacobSingh: include /includes/install.inc in module_enable() which is required when enabling modules for the first time.

- Patch #661420 by justinrandell, David_Rothstein: made installation of modules much more efficient.

#619666 by effulgentsia, casey, and catch: Changed Introduce new pattern for drupal_static() in performance-critical functions.

- Patch #623992 by catch: performance improvement: reduce {system} database hits on every page request.

- Patch #200931 by Darren Oh, asimmonds: fixed schema not being available in hook_install()/hook_enable().

- Patch #557542 by CorniI, catch, fago, Crell, sun | pwolanin, chx, webchick, mattyoung, alexanderpas, justinrandell, dropcube, moshe weitzman, Damien Tournoud, Rob Loach, Dries: cache module_implements() for better performance and scalability.

#497118 by chx, catch, pwolanin, JoshuaRogers, and Jacob Singh: Remove the function registry. While the hope was that this would result in improved performance for low-end hosts, it comes at the expense of critical development experience problems and less benefit than something like APC. Class registry remains intact to facilitate autoloading.

Of all the patches to accidentally commit without a message. :( Rolling back registry rip. Let's try that again.

#509398 by adrian: Turned install profiles into modules with full access to the Drupal API. Almost all WTFs/minute now removed from install profiles. Woohoo! :D

#517814 by jmstacey, justinrandell, pwolanin, drewish, Jody Lynn, aaron, dopry, and c960657: Converted File API to stream wrappers, for enhanced private/public file handling, and the ability to reference other storage mechanisms such as s3:// and flicker://.

#533584 by chx, dww, and Nick Lewis: Allow version-level dependency support to work with beta, rc, etc.

- Patch #211747 by chx, alex_b, dww: allow specifying version information as part of module dependencies.

#482346 by Berdir: Move module installation logic to module_enable() to prevent errors upon enabling modules.