Red Hat says it has amassed over 2,000 patents and won't enforce them if the technologies they describe are used in properly-licensed open-source software. From a report: The company has made more or less the same offer since 2002, when it first made a "Patent Promise" in order to "discourage patent aggression in free and open source software." Back then the company didn't own many patents and claimed its non-enforcement promise covered 35 per cent of open-source software. The Promise was revised in order to reflect the company's growing patent trove and to spruce up the language it uses to make it more relevant. The revised promise "applies to all software meeting the free software or open source definitions of the Free Software Foundation (FSF) or the Open Source Initiative (OSI)." [...] It's not a blank cheque. Hardware isn't covered and Red Hat is at pains to point out that "Our Promise is not an assurance that Red Hat's patents are enforceable or that practicing Red Hat's patented inventions does not infringe others' patents or other intellectual property." But the company says 99 percent of FOSS software should be covered by the Promise.