Notable software patents include: Software patents and patents on computer-implemented inventions (CII) are a class of patents and one of many legal aspects of computing. ...

• RSA Patent - a famous software patent on the ground-breaking and highly unobvious algorithm for public key encryption, widely used for secure communications in many industries nowdays (RSA)
• Karmarkar Patent - a famous software patent on the highly non-trivial mathematical algorithm for solving linear programming problems (http://www.apic.jiii.or.jp/p_f/text/text/2-05.pdf)
• Unisys acquired a patent on LZW compression, a fundamental part of the widely-used GIF graphics format. Unisys published the compression algorithm, but did not make it clear that it was applying for a patent. CompuServe then developed a graphics format (based on well known publication), and, having no reason to choose otherwise (not going to the trouble of checking a patent status of the published algorithm), chose the LZW compression algorithm. Unisys waited until the GIF algorithm was widely used, and then demanded royalties for users and developers who until then had had no idea of the issue. It is uncertain if Unisys delayed intentionally or not, but it is clear that many developers were very angry at the Unisys response. This resulted in re-development of a new graphics format, PNG, which failed to capture much popularity outside of the open-source community.
• The popular music format MP3 is encumbered by a number of patents, which were only enforced once the format became popular. This resulted in several GNU/Linux systems dropping support for MP3, and in re-development of new audio formats—notably Ogg Vorbis.
• British Telecom sued Prodigy over U.S. Patent 4,873,662, claiming that Prodigy infringed its patent on web hyperlinks. However, after costly litigation, a court found for Prodigy, ruling that British Telecom's patent did not actually cover web hyperlinks. [1] Hyperlinks were first described in 1945 in the landmark paper As We May Think, as well as in the widely-known project Xanadu starting in the 1960s.
• Cadtrack's U.S. Patent 4,197,590 covers drawing a cursor on a screen using XOR, which allows removal by XORing it again, thus eliminating the need for backing store.
• Amazon.com successfully sued Barnes and Noble for violating its "One click buy".
• Amazon.com's method and system for conducting a discussion relating to an item under United States Patent 6,525,747 [2].
• Eolas successfully sued Microsoft for $521 million for the "browser plugin patent". See Eolas for details.
• Compton's NewMedia was awarded a submarine patent in 1993, which had been filed five years before, for "A search system [that] uses a multimedia database consisting of text, picture, audio, and animated data." Compton's announced their patent at the height of the excitement over CD-ROM software and claimed this patent covered all multimedia software, and announced a royalty payment schedule. An outcry ensued that this was an attempt to patent something that had been in active use for many years, and the furor was so great that the Patent Office commissioner quickly started an "reexamination" to re-investigate the claim. It seemed that the PTO had only reviewed existing patents for prior art, and not the wide body of prior art in the field that had not been patented. The patent was voided in 1994.
• Stac Electronics sued Microsoft for patent infringement when Microsoft introduced a data compression scheme into MS-DOS which resembled (was stolen from Stac, as the jury had found) Stac's Stacker software. Stac was awarded $120 million by a jury in 1994 and Microsoft was ordered to recall versions of MS-DOS with the infringing technology. Subsequently Microsoft and Stac settled the case; Microsoft promised not to appeal, paid Stac $43 million, and purchased $40 million of preferred Stac stock.
• The Wiki system might be patented by Family Systems Limited, at least according to some interpretations.
• Microsoft did patent the file structure of the ASF container format and invoked its patent against VirtualDub
• State Street Bank decision essentially made business methods patentable in the USA.
• Acacia Technologies claims to have patented compressing video for distribution over the web.
• Commerce One has many patents that were recently sold.
• The Microsoft FAT patents were used to collect considerable royalties but were successfully challenged.
• The U.S. Patent 5,710,835 owned by Lizardtech, Inc., is claimed to cover JPEG 2000 image compression format. However, Lizardtech, Inc. lost the trial against Earth Resource Mapping.
• Xerox claimed its U.S. Patent 5,596,656 was infringed by Palm's handwriting recognition technique called Graffiti. In 2001, Palm was forced to change the software its users had grown accustomed to. In 2004, a judge threw out the Xerox patent based on prior art.
• The U.S. Patent 6,754,891 issued to Red Hat for a debugger system.
• The U.S. Patent 4.698.672 owned by Forgent Networks is claimed to cover the JPEG image compression format.

In cryptography, RSA is an algorithm for public key encryption. ... Unisys Corporation (NYSE: UIS) is a provider of information technology services and solutions with operations across the world. ... LZW (Lempel-Ziv-Welch) is a lossless data compression algorithm. ... A rotating globe in GIF format. ... CompuServe, (CompuServe Information Services, or CIS for short), was the first major commercial online service in the US, dominating the field during the 1980s and remaining a major player through the mid-1990s when it was sidelined by the rise of GUI-based services such as America Online (AOL). ... PNG (Portable Network Graphics) is a lossless bitmap image format. ... MP3 is a popular digital audio encoding and lossy compression format invented and standardised in 1991 by a team of engineers working in the framework of the ISO/IEC MPEG audio committee under the chairmanship of Professor Hans Musmann (University of Hannover - Germany). ... Tux, a penguin, is the official Linux mascot. ... Vorbis is an open and free audio compression (codec) project from the Xiph. ... BT Group plc (which trades as just BT, and is commonly known by its former name, British Telecom) is the privatised former British state telecommunications operator. ... A hyperlink, or simply a link, is a reference in a hypertext document to another document or other resource. ... 1945 was a common year starting on Monday (link will take you to calendar). ... Vannevar Bushs essay As We May Think, first published in The Atlantic Monthly in July 1945, argued that as humans turned from war, scientific efforts should shift from increasing physical abilities to making all previous collected human knowledge more accessible. ... Project Xanadu was founded by Ted Nelson in 1960 as the original hypertext project. ... The 1960s, or The Sixties, in its most obvious sense refers to the decade between 1960 and 1969, but the expression has taken on a wider meaning over the past twenty years. ... Exclusive disjunction (usual symbol xor) is a logical operator that results in true if one of the operands (not both) is true. ... Amazon. ... Amazon. ... Eolas is a United States company and patent licensee. ... Microsoft Corporation (NASDAQ: MSFT) is the worlds largest software company, with over sixty thousand employees and headquarters in various countries as of May 2004. ... Eolas is a United States company and patent licensee. ... Submarine patent is an informal legal term for a patent published long after the original application was filed. ... The CD-ROM (an abbreviation for Compact Disc Read-Only Memory (ROM)) is a non-volatile optical data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. ... Multimedia is the use of several different media to convey information (text, audio, graphics, animation, video, and interactivity). ... Stac Electronics was an engineering company founded in 1984 by four friends at Caltech. ... Microsoft Corporation (NASDAQ: MSFT) is the worlds largest software company, with over sixty thousand employees and headquarters in various countries as of May 2004. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... Stac Electronics was an engineering company founded in 1984 by four friends at Caltech. ... Wikibooks has more about this subject: Wiki Science A wiki is a web application that allows users to add content, as on an Internet forum, but also allows anyone to edit the content. ... Microsoft Corporation (NASDAQ: MSFT) is the worlds largest software company, with over sixty thousand employees and headquarters in various countries as of May 2004. ... Advanced Streaming Format (or ASF, later renamed into Advanced Systems Format) is Microsofts proprietary digital audio/digital video container format, especially meant for streaming. ... VirtualDub is an open source video capture and linear processing tool for Microsoft Windows. ... The decision of July 23, 1998 of the United States Court of Appeals for the Federal Circuit in State Street Bank & Trust Company v. ... Acacia Techologies is used loosely to refer to Acacia Research Corporation and its subsidiary Acacia Media Technologies. ... Commerce One was one of the pioneering e-commerce companies. ... File Allocation Table (FAT) is a file system that was developed for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ... JPEG 2000 is a wavelet-based image compression standard. ... Xerox Corporation (NYSE: XRX) is the worlds largest supplier of toner-based (dry ink) photocopier machines and associated supplies. ... Handwriting recognition is the ability of a computer to receive intelligible written input. ... A chart of the Graffiti characters (full size) Graffiti is the handwriting recognition software used in PDAs based on the Palm OS. Graffiti was originally written by Palm as an alternate recognition system for the Apple Newton MessagePad, when NewtonOS 1 couldnt recognize handwriting very well at all. ... Alternate meanings: See Red hat Red Hat, Inc. ... A debugger is a computer program that is used to debug (and sometimes test or optimize) other programs. ... Forgent Networks is a software company that specializes in meeting and scheduling programs. ... A photo of a flower compressed with successively higher compression ratios from left to right. ...

External links

• Gauss Database of suspected European Software patents
• List of Example patents on the AEL wiki
• Microsoft and Stac Electronics
• Examples by Gordon Irlam
• FFII: Well documented examples
• European Software Patents: Assorted Examples
• European Software Patent Horror Gallery
• Ole Tange's ziki: Patent index with 20.000 European software patents
• European Patent applications from Microsoft in 2004, nearly 2 per day