PEAR (PHP Extension and Application Repository) was the original package distribution system for PHP. Before Composer became the standard dependency manager, PEAR channels served as the primary mechanism for distributing PHP libraries, framework components, and development tools.
In the context of Zend Framework, PEAR provided one of the supported installation methods for getting the framework onto a development machine or server. The pear install command could pull Zend Framework packages from registered channels, handling version resolution and making the library available through the PHP include path.
A PEAR channel was essentially a hosted repository that advertised available packages, their versions, and their dependencies. Developers would discover a channel, register it locally with pear channel-discover, and then install packages from it. The system handled dependency resolution within the PEAR ecosystem, though it could not manage non-PEAR dependencies.
For Zend Framework specifically, the installation looked something like registering the appropriate channel and then running pear install zend/zend. This placed the framework files into the global PEAR directory, which was already on PHP's include path by default on most installations.
PEAR had several practical limitations that drove the adoption of Composer. It installed packages globally rather than per-project, making it difficult to run different library versions across projects on the same machine. It lacked the deep dependency resolution that Composer provides. And its channel infrastructure required dedicated server-side tooling that added friction for library maintainers.
Composer solved these problems by installing dependencies locally in a vendor directory, resolving nested dependency trees automatically, and using a simple composer.json file that could be committed to version control. The transition from PEAR to Composer was one of the most significant infrastructure shifts in the PHP ecosystem.
While PEAR channels are no longer the recommended way to install PHP packages, understanding the PEAR era helps when working with older PHP codebases that may still reference PEAR-style include paths, naming conventions (underscored class names mapping to directory structures), or installation instructions that predate Composer.
The Survive The Deep End chapter on installing Zend Framework covers both the original PEAR method and the modern Composer alternative.