EMC has won the latest patent battle in the IT industry, this time against Hewlett Packard and is seeking a court injunction to prevent it shipping its CASA storage appliance.

A jury verdict, at a Massachusetts district court yesterday, found that HP has infringed three of EMC's software patents relating to the creation of identical copies, or mirrors, of system files. Two of the patents cover a remote mirroring technique used in EMC's Symmetrix Remote Data Facility, EMC said in a statement. The other covers a mirroring technique used in the company's TimeFinder software.

The original lawsuit was filed in October 2000 against StorageApps, but HP became involved when it acquired the company in July 2001. Damages have not yet been set, said Brian Garabedian, an HP spokesman. And perhaps unsurprisingly HP doesn't entirely agree with the verdict. "HP disagrees with the jury's decision of infringement of the EMC patents asserted against HP," he said. However, he added, HP is "prepared to take whatever steps necessary to minimise the potential impact to existing customers and channel partners."

That impact could be quite significant if EMC manages to prevent HP from selling CASA storage appliance because it, currently, includes the remote and local mirroring software that the patents cover.

As ever though, things are a little more complicated. HP and EMC are also involved in a separate California lawsuit involving seven patents relating to software and hardware in EMC's Symmetrix and Clariion product lines. That case is expected to go to trial in 2005. EMC would have a useful bargaining chip if it gets an injunction against HP. Otherwise, once that case is decided, no doubt the two companies will agree to patent share and the whole patent circus can move onto the next town.