APCu is userland caching: APC stripped of opcode caching in preparation for
the deployment of Zend Optimizer+ as the primary solution to opcode caching
in future versions of PHP.
APCu has a revised and simplified codebase, by the time the PECL release is
available, every part of APCu being used will have received review and where
necessary or appropriate, changes.
Simplifying and documenting the API of APCu completely removes the barrier to
maintenance and development of APCu in the future, and additionally allows us
to make optimizations not possible previously because of APC's inherent
complexity.
APCu only supports userland caching (and dumping) of variables, providing an
upgrade path for the future. When O+ takes over, many will be tempted to use
3rd party solutions to userland caching, possibly even distributed solutions;
this would be a grave error. The tried and tested APC codebase provides far
superior support for local storage of PHP variables.
