Rackspace Cloud PHP SDK by Rackspace is an open-source PHP library released under the Apache 2.0 license. This SDK supports both Rackspace and OpenStack services, some of the services include Cloud Block Storage, Cloud DNS, Cloud Databases, and Cloud Files.
The trouble with building mobile computing applications is that end users have little tolerance when it comes to how they expect those applications to behave. Never mind the fact that mobile applications are amongst some of the most challenging to create; the second somebody has a less than optimal experience they're off to another application. Needless to say, that puts a lot of pressure on mobile application developers.