What is Cydia? What is Rock?

Cydia is a software application for iOS that lets a user browse and download applications for a jailbroken iPhone, iPod Touch or iPad. It was developed by Jay Freeman (also known as “saurik”). Cydia was originally released as an open-source alternative to Installer.app on iOS 1.1.x, but quickly became the most popular package manager upon 2.0′s release.

Cydia provides a more user-friendly graphical user interface for some open-source software-installation tools originally developed for Debian (specifically APT, and the dpkg package management system). Cydia’s repositories allow the installation of software packages, most of which are available to download at no cost. Cydia also includes the Cydia Store, which offers a number of applications for sale. Both free and paid software packages are downloaded directly to an iOS device, to the same location as Apple’s pre-installed applications (the /Applications directory).

The name “Cydia” is an allusion to the Codling Moth (“Cydia pomonella”), which made famous the “worm in the apple.” It is used as a reference to Apple Inc.

Rock is a Cydia alternative. It extends the user experience from the Web, to the Desktop, and onto the Mobile Device.  From all three channels, users are able to browse, select to trial, and purchase an application.  It is the first mobile market provider to fully integrate a rich desktop client with web and mobile devices.

The biggest difference between Cydia and Rock is speed. Rock is far more speedier than Cydia, but has a smaller database.

Excluding the speed and database differences, both programs have similar features.