Hewlett-Packard has filed a patent infringement lawsuit against EMC, charging that its competitor uses HP technology in both its storage hardware and software products.

Management-systems developer EMC later responded with a patent infringement suit of its own.

HP filed the complaint in the US District Court for the Northern District of California, claiming that EMC's Symmetrix and Clariion storage systems and its TimeFinder software infringe seven patents held by HP.

This action follows similar suits filed earlier this year by EMC and Hitachi against each other. HP resells a number of Hitachi's high-end storage systems, and cited its relationship with the company as one reason for filing the lawsuit, according to a statement.

Vice president of marketing for HP's network storage solutions Bob Schultz said: "This means we want EMC to stop using our intellectual property, and we want them to pay us for it."

HP, based in Palo Alto, California, and EMC are fierce rivals in the market for data-storage systems and software. The companies have been working to push standards in the industry that will allow competing vendors' products to work with one other. Despite these efforts, HP said in the statement that it "has a responsibility to ensure that, as we compete in the marketplace, we are not competing against our own intellectual property".

HP claims EMC has violated patents for transferring data between different storage media, reducing the number of reads and writes in a RAID (redundant array of independent disks) configuration, linking host computers via a switching network to storage systems, handling disk failures in a RAID configuration, methods for presenting logical units to host computers and technology used between storage systems and power supplies.

HP is seeking payment for past infringement as well as injunctive relief against EMC to use technology covered by the patents.