NetApp：NetApp 針對 Sun 的 ZFS 檔案系統提出專利訴訟原文出處：NetApp Blog http://blogs.netapp.com/dave/2007/09/netapp-sues-sun.html稍後再來翻譯NetApp Sues Sun for ZFS Patent InfringementThis morning, NetApp filed an IP (intellectual property) lawsuit against Sun. It has two parts. The first is a “declaratory judgment”, asking the court to decide whether we infringe a set of patents that Sun claims we do. The second says that Sun infringes several of our patents with its ZFS technology.How did we get here?Like many large technology companies, Sun has been using its patent portfolio as a profit center. About 18 months ago, Sun’s lawyers contacted NetApp with a list of patents they say we infringe, and requested that we pay them lots of money. We responded in two ways. First, we closely examined their list of patents. Second, we identified the patents in our portfolio that we believe Sun infringes.With respect to Sun’s patent claims, our lawsuit explains that we do not infringe, and – in fact – that they are not even valid. As a result, we don’t think we should be paying Sun millions of dollars.On the flip side, our suit points out that Sun’s ZFS appears to infringe several of NetApp’s WAFL patents. It looks like ZFS was a conscious reimplementation of our WAFL filesystem, with little regard to intellectual property rights. Here’s what creators of ZFS have to say: “The file system that has come closest to our design principles, other than ZFS itself, is WAFL … the first commercial file system to use the copy-on-write tree of blocks approach to file system consistency.” One of the first patents I filed at NetApp describes this “copy-on-write tree of blocks” technique in detail.We filed suit against Sun because after we pointed out the WAFL patents, their lawyers stopped getting back to us. The first part of our suit is a declaratory judgment. It’s complicated, but the basic idea is that Sun claims we infringe their patents, so we are requesting a trial to show that’s not true. In essence, a declaratory judgment calls their bluff. It allows us to force a legal conclusion, rather than leaving this threat hanging over our heads. The second part is a complaint against Sun for infringing several WAFL patents with ZFS.As we file this case, I’m painfully aware of the bad feelings that many people have about IP lawsuits. Business people sometimes view them as the last gasp of a dying company, while some technical folks view them as evil under any circumstances. In this case, I doubt that business people will be too concerned, given our growth rate, profitability, and the fact that we are responding to Sun’s claims against us. I expect skeptical technical people to be harder to comfort.This case is especially sensitive, because Sun has released ZFS as open source. It is admirable to contribute to open source. I have done it personally, although it was a long time ago that I was writing code, and NetApp has also contributed as a company. But it doesn’t help the open source movement to give away code that is encumbered with someone else’s patent rights. The sooner we determine the true status of ZFS, the better it will be for everyone. NetApp certainly doesn’t believe that we can somehow erase every copy of ZFS that has been downloaded. (Impossible!) This lawsuit isn’t about downloads for personal or non-commercial use; it is about what Sun is doing.We could have a long debate about the merits of the patent system. (I expressed my own qualms here.) But like it or not, it’s the law of the land. Here’s an analogy. Suppose you own a pro football team, and you really believe that touch football would be safer and more humane than tackle. You can lobby all you want to try to change rules, but until you are successful, I recommend that your team keep wearing pads and helmets. NetApp is participating in attempts to reform the patent system, but meanwhile we will play by the rules as they exist.In closing, let me say that the legal system is a method of resolving disputes between companies, but it does not mean we are “at war”. During this process, we will continue to support all Sun products, including ZFS filesystems that use NetApp storage. It is not in anyone’s interest – Sun’s or ours – to leave a bunch of customers in the lurch. I hope that Sun will respond in kind.Non-technical people can stop reading now.It is important to me that technical readers not confuse NetApp with SCO, so in our lawsuit, we provided a starting point for people who want to dig deeper. This is not an exhaustive analysis of our case. We simply highlight one particular patent and one particular aspect of ZFS to help people see that this case of infringement is real.Here’s how the ZFS designers describe filesystem consistency:The best way to avoid file system corruption due to system panic or power loss is to keep the data on the disk self-consistent at all times, as WAFL does. To do so, the file system needs a simple way to transition from one consistent on-disk state to another without any window of time when the system could crash and leave the on-disk data in an inconsistent state.In the ZFS paper, search for uberblock, and compare its role in filesystem consistency with the role of the root inode and file system information structure in our patent 5,819,292. Read claim 4 and its descendents, which describe our tree-of-blocks consistency technique. Claim 8 and its descendents describe efficient snapshot creation based on the tree-of-blocks. Some more useful references are here (see pages 7 and 8), here, and here.We hope that this level of openness will help raise the bar on how people pursue intellectual property suits.Let me insert the usual legal disclaimer: I’ve quoted our complaint, but beyond that, I won’t engage in any public comment on the technical details of our case while it is pending.