Editing File Allocation Table (section)

== <span id="Legal"></span>Patents ==

Microsoft applied for, and was granted, a series of patents for key parts of the FAT file system in the mid-1990s. All four pertain to long-filename extensions to FAT first seen in [[Windows 95]]: U.S. patent 5,579,517,<ref name=patent5579517>{{cite patent |inventor1-last=Reynolds |inventor1-first=Aaron R. |inventor2-last=Adler |inventor2-first=Dennis R. |inventor3-last=Lipe |inventor3-first=Ralph A. |inventor4-last=Pedrizetti |inventor4-first=Ray D. |title=Common name space for long and short filenames |issue-date=1996 |patent-number=5579517 |country-code=US }}</ref> U.S. patent 5,745,902,<ref>{{cite patent |inventor1-last=Miller |inventor1-first=Thomas J. |inventor2-last=Kimura |inventor2-first=Gary D. |title=Method and system for accessing a file using file names having different file name formats |issue-date=1998 |patent-number=5745902 |country-code=US }}</ref> U.S. patent 5,758,352,<ref name=patent5758352>{{cite patent |inventor1-last=Reynolds |inventor1-first=Aaron R. |inventor2-last=Adler |inventor2-first=Dennis R. |inventor3-last=Lipe |inventor3-first=Ralph A. |inventor4-last=Pedrizetti |inventor4-first=Ray D. |title=Common name space for long and short filenames |issue-date=1998 |patent-number=5758352 |country-code=US }}</ref> U.S. patent 6,286,013 (all expired since 2013).<ref>{{cite patent |inventor1-last=Reynolds |inventor1-first=Aaron R. |inventor2-last=Adler |inventor2-first=Dennis R. |inventor3-last=Lipe |inventor3-first=Ralph A. |inventor4-last=Pedrizetti |inventor4-first=Ray D. |title=Method and system for providing a common name space for long and short file names in an operating system |issue-date=1996 |patent-number=6286013 |country-code=US }}</ref>

On December 3, 2003, Microsoft announced<ref name="Microsoft_2003_FAT32" /> that it would be offering licenses for use of its FAT specification and "associated intellectual property", at the cost of a {{US$|0.25}} royalty per unit sold, with a {{US$|250000}} maximum royalty per license agreement.<ref name="Microsoft_FAT_File_System" /> To this end, Microsoft cited four patents on the FAT file system as the basis of its intellectual property claims.

In the EFI FAT32 specification,<ref name="efi" /> Microsoft specifically grants a number of rights, which many readers have interpreted as permitting operating system vendors to implement FAT.<ref>{{cite web |url=https://www.youtube.com/watch?v=V2aq5M3Q76U | archive-url=https://ghostarchive.org/varchive/youtube/20211102/V2aq5M3Q76U| archive-date=2021-11-02 | url-status=live|title=EFI and Linux: the future is here, and it's awful |first=Matthew |last=Garrett |date=January 19, 2012 |work=[[linux.conf.au]] |publisher=YouTube |access-date=2014-01-12 }}{{cbignore}}</ref> Non-Microsoft patents affecting FAT include: U.S. patent 5,367,671, specific to the [[OS/2]] extended object attributes (expired in 2011).<ref>{{cite patent |inventor1-last=Feigenbaum |inventor1-first=Barry A. |inventor2-last=Miro |inventor2-first=Felix |title=System for accessing extended object attribute (EA) data through file name or EA handle linkages in path tables |issue-date=1994 |patent-number=5367671 |country-code=US }}</ref>

=== Challenges and lawsuits ===
The Public Patent Foundation (PUBPAT) submitted evidence to the [[USPTO|US Patent and Trademark Office]] (USPTO) in 2004 disputing the validity of U.S. patent 5,579,517,<ref name=patent5579517 /> including prior art references from [[Xerox]] and IBM.<ref>{{cite web |url=http://www.pubpat.org/assets/files/MicrosoftFAT/Reynolds_517_Reexam_Request.pdf |title=PUBPAT's Request for Reexamination of Microsoft's FAT Patent |last=Ravicher |first=Daniel B. |publisher=Public Patent Foundation |date=April 15, 2004 |access-date=2014-01-12 |archive-date=2013-06-07  |archive-url=https://web.archive.org/web/20130607091551/http://www.pubpat.org/assets/files/MicrosoftFAT/Reynolds_517_Reexam_Request.pdf |url-status=live }}</ref> The USPTO opened an investigation and concluded by rejecting all claims in the patent.<ref>{{cite web |url=http://www.pubpat.org/assets/files/MicrosoftFAT/Reynolds_517_Rejected_040916.PDF |title=Patent Office's Office Action Rejecting Microsoft FAT Patent |author=USPTO |publisher=Public Patent Foundation |date=September 30, 2004 |access-date=2014-01-12 |author-link=USPTO |archive-date=2013-05-26  |archive-url=https://web.archive.org/web/20130526003038/http://www.pubpat.org/assets/files/MicrosoftFAT/Reynolds_517_Rejected_040916.PDF |url-status=live }}</ref> The next year, the USPTO further announced that following the re-examination process, it affirmed the rejection of '517 and additionally found U.S. patent 5,758,352<ref name=patent5758352 /> invalid on the grounds that the patent had incorrect assignees.

However, in 2006, the USPTO ruled that features of Microsoft's implementation of the FAT system were "novel and non-obvious", reversing both earlier decisions and leaving the patents valid.<ref name="CNET_2006-01-10" />

In February 2009, Microsoft filed a [[patent infringement]] lawsuit against [[TomTom]] alleging that the device maker's products infringe on patents related to [[#VFAT|VFAT]] long filenames. As some TomTom products are based on [[Linux]], this marked the first time that Microsoft tried to enforce its patents against the Linux platform.<ref name="ARSTechnica_2009" /> The lawsuit was settled out of court the following month with an agreement that Microsoft be given access to four of TomTom's patents, that TomTom will drop support for the VFAT long filenames from its products, and that in return Microsoft not seek legal action against TomTom for the five-year duration of the settlement agreement.<ref name="CNET_2009" />

In October 2010, Microsoft filed a patent infringement lawsuit against [[Motorola]] alleging several patents (including two of the VFAT patents) were not licensed for use in the [[Android (operating system)|Android]] operating system.<ref name="Microsoft_Motorola" /> They also submitted a complaint to the [[United States International Trade Commission|ITC]].<ref name="ARSTechnica_2010" />
Developers of open source software have designed methods intended to circumvent Microsoft's patents.<ref name="ArsTechnica_2009" /><ref name="DesktopLinux_2009" />

In 2013, patent EP0618540 "common name space for long and short filenames" (expired since 2014<ref>{{Cite patent|title=Common name space for long and short filenames|gdate=1994-03-31|url=https://patents.google.com/patent/EP0618540B1/en}} {{Cite web |url=https://patents.google.com/patent/EP0618540B1/en |title=EP0618540B1 - Common name space for long and short filenames - Google Patents |access-date=2021-05-07  |archive-date=2020-03-28  |archive-url=https://web.archive.org/web/20200328120538/https://patents.google.com/patent/EP0618540B1/en |url-status=bot: unknown }}</ref>) was invalidated in Germany.<ref>{{cite web |url=http://www.fosspatents.com/2013/12/federal-patent-court-of-germany.html |title=Federal Patent Court of Germany invalidates Microsoft FAT patent, appeals court may disagree |first=Florian |last=Müller |publisher=FOSS Patents |date=December 5, 2013 |access-date=2014-01-12 |archive-date=2014-01-04  |archive-url=https://web.archive.org/web/20140104122540/http://www.fosspatents.com/2013/12/federal-patent-court-of-germany.html |url-status=live }}</ref> After the appeal was withdrawn, this judgment became final on the 28th October 2015.<ref>{{cite web |url=https://www.ifross.org/artikel/bundespatentgericht-erkl-rt-vfat-patent-erneut-f-r-nichtig |title=Bundespatentgericht erklärt VFAT-Patent erneut für nichtig |first=Stefan |last=Labesius |publisher=ifrOSS |date=May 28, 2017 |access-date=2019-08-02 |archive-date=2019-08-02  |archive-url=https://web.archive.org/web/20190802132657/https://www.ifross.org/artikel/bundespatentgericht-erkl-rt-vfat-patent-erneut-f-r-nichtig |url-status=live }}</ref>