Although the deliverables are mostly backward compatible with Virgo 3.0.x, we decided to indicate the importance of the release by bumping the version from 3.0 to 3.5.
All Virgo deliverables are now launched using the Equinox launcher and have a corresponding directory structure which is slightly different from that of 3.0.x. All the deliverables can all be initially provisioned using p2, which is useful, for instance, when setting up remote nodes or automating installation.
There are two new deliverables which the team is pretty excited about. Virgo nano is a cut-down subset of the kernel. It supports hot deployment of bundles via the pickup directory, the Gogo shell, a single (kernel) region, and the medic component which provides Virgo's basic diagnostic capabilities.
The second new deliverable is Nano Web which is essentially Gemini Web -- the Apache Tomcat based reference implementation of the OSGi Web Applications specification -- running on Nano. In addition to Nano's features, Nano Web supports hot deployment of Web Application Bundles and WAR files.
Compared to the kernel-based deliverables, which are already pretty small and fast, Nano starts much faster and has a much smaller footprint as the following charts indicate.1
Both Nano and Nano Web can be provisioned with application bundles at runtime using p2. The kernel based deliverables can only be initially provisioned using p2. Applications are then deployed into the user region in the usual way. This provisioning limitation in p2 triggered the initial development of Nano, although Nano soon appeared to have other benefits such as smaller runtime footprint (particularly important in the cloud) and the possibility of using PDE for bundle development. Also, Nano Web is likely to integrate additional enterprise Java components in the future to support applications written for the Java EE web profile.
There are a number of other interesting features in 3.5.0 including integrated support for the OSGi Blueprint Service, several significant kernel enhancements, and various dependency upgrades - all described in the release notes.
Additionally, Virgo Bundlor 1.1.1 and the Greenpages 2.5.0 sample application are released in association with Virgo 3.5.0.
In parallel with the development of Virgo 3.5.0, the Virgo IDE tooling has been overhauled and will be released in the next few weeks. Meanwhile you can use milestones and snapshots of the new tooling as described on the tooling wiki page.
Please see the release notes for further details of Virgo 3.5.0 and the migration notes for information about upgrading from Virgo 3.0.x.
Footnote:
- Startup times are approximate. Measurements were taken using Mac OS X 10.7.4, and Java 1.6.0_33 on a Mac Pro with 12 GB RAM and 2 x 2.66 GHz dual core Intel Xeon processors.