Zend Server, a commercial product developed by the Zend Corporation (since aquired by RougeWave) have a feature called OPCache.
Stand alone open source PHP also has a feature called OPcache, available since PHP 5.5.
Are these the same system? Or are there differences in the OPcache offered by Zend Server?
Throughout PHPs life time there have been a number of OpCode caches; one of the first was from Zend (which has had several names), however it was proprietary. Therefore, for the last few years the primary cache being used has been APC — Alternative PHP Cache. While APC is great, it lacks some features found in Zend’s offering, and additionally lacked maintainers to bring it up to speed for the latest PHP versions.
With PHP 5.5, Zend open sourced their cache offering, under the new name of Zend OpCache, and contributed it to the PHP project — it is now included with PHP itself, in addition to being available for older PHP versions going all the way back to PHP 5.2!
Zend OpCache appears to be more performant than APC, more fully featured, and more reliable. However, Zend OpCache does not contain the secondary feature offered by apc, a userland shared memory cache — to mitigate this issue, a new extension “apcu” has been released, which provides just the userland caching, and is 100% compatible with the original APC implementation.
