Editing Mmap (section)

==History==
The original design of memory-mapped files came from the [[TOPS-20]] operating system. <code>mmap</code> and associated systems calls were designed as part of the [[Berkeley Software Distribution]] (BSD) version of Unix. Their API was already described in the 4.2BSD System Manual, even though it was neither implemented in that release, nor in 4.3BSD.<ref>{{cite report |author1=William Joy |author-link=Bill Joy |author2=Eric Cooper |author3=Robert Fabry |author3-link=Bob Fabry |author4=Samuel Leffler |author4-link=Samuel Leffler |author5=Kirk McKusick |author5-link=Marshall Kirk McKusick |author6=David Mosher |title=4.2BSD System Manual |url=http://www.cilinder.be/docs/bsd/4.2BSD_Unix_system_manual.pdf |year=1983 |publisher=[[Computer Systems Research Group]], [[University of California, Berkeley]]}}</ref> [[Sun Microsystems]] had implemented this API, though, in the 4.0 release of their [[SunOS]] operating system.<ref>{{cite web |url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=a36b01c8fd5071f64b981dd3ffc66a6bce56736d#:~:text=6.1.&text=In%20general%2C%20the%20kernel%20uses,'buffer%20cache''). |title=Virtual Memory Architecture in SunOS |first1=Robert A. |last1=Gingell |first2=Joseph P. |last2=Moran |first3=William A. |last3=Shannon}}</ref> The BSD developers at [[University of California, Berkeley]] unsuccessfully requested Sun to donate its implementation; 4.3BSD-Reno was instead shipped with an implementation based on the virtual memory system of [[Mach (kernel)|Mach]].<ref name="opensources">{{cite encyclopedia |title=Twenty Years of Berkeley Unix: From AT&T-Owned to Freely Redistributable |first=Marshall Kirk |last=McKusick |authorlink=Marshall Kirk McKusick |encyclopedia=Open Sources: Voices from the Open Source Revolution |year=1999 |publisher=O'Reilly}}</ref>