The patents appear to concern core functions within CASA, which HP candidly described yesterday as a relatively low-volume product.

EMC, which has a long established hardball reputation, said yesterday that it intends to seek an injunction based on the court action and is not prepared to speculate whether it will negotiate some form of settlement with HP. Steve Duplessie, analyst at the Enterprise Storage Group said however: Negotiation is exactly what will happen. I don’t know what EMC’s end-goal was, but they spent a lot of money on this action. I’d be very surprised if money changes hands – it’s much more likely they’ll swap technologies.

In a statement HP said it is considering whether to appeal against the verdict. Suggesting that a product recall is at least possible, it said it will take whatever steps are necessary to protect existing CASA owners and channel resellers. In September 2002 HP launched its own patent-infringement action against EMC, which will be heard next year.

One of the key benefits of a virtualization device such as CASA is the ability to replicate data between disk arrays. EMC said the three patents named in its lawsuit concerned its SRDF and TimeFinder mirroring or replication products.

Eighteen months ago HP said CASA sales took off when the company repositioned it as a replication device rather than a virtualization system.

HP has not had a happy history with storage virtualization. In 2000 it paid out $350m in a stock-swap acquisition of StorageApps Inc, the original developer of CASA. At that time virtualization was tipped for strong sales, but since then it has only sold moderately well.

At the beginning of this year HP put on indefinite hold its previously very public and ambitious plans to combine CASA with what was Compaq’s Versastor out-of-band virtualization project. HP cited lack of demand as the reason for its decision. Versastor had already undergone major changes in its technology direction.

EMC and HP’s court case was held in the district court of Worcester, Massachusetts. The lawsuit was first launched in 2000, against StorageApps.