Google, whose lawyers hardly ever get out of the courtroom (mostly on the defendant side), has added another 79 patents to its will-not-sue pledge. The patents are for software the company uses to run its data center infrastructure.

Google made its first Open Patent Non-Assertion Pledge in April, when it named 10 patents related to MapReduce – the computing model that became the basis for Apache Hadoop. The pledge means Google will not sue anybody for using technologies the patents describe, unless it gets sued over these technologies first.

Duane Valz, the company's senior patent counsel, announced addition of the nearly 80 patents to the pledge in a blog post Thursday, explaining that the move was about protecting the open-source-software movement from patent trolls.

“Open-source software has accelerated the pace of innovation in computing, leading to better products and services at lower cost,” he wrote. “But as the impact of open-source software has grown, so too has the number of patent attacks against it.”

Among the new patents on the list are distributed-storage-management technologies, all of which have to do backup and recovery, and many middleware patents. There are also a few patents for distributed-database management.

These are patents Google bought from CA Technologies and IBM, Valz explained. The two were some of the first companies to make such patent non-assertion pledges.

Google gets sued by companies and public-sector organizations on a regular basis and acts as a plaintiff from time to time as well.

The biggest recent lawsuit of the latter category is Google's attack on British Telecom in response the telco's patent lawsuit against itself, according to a report by Wired. As the report explains, it is common for a defendant company to sue the plaintiff to gain leverage that comes with a threat of a damage claim.