Editing RSX-11 (section)

===Legal ownership, development model and availability===
RSX-11 is [[proprietary software]]. [[Copyright]] is asserted in binary files, source code and documentation alike. It was entirely developed internally by Digital. Therefore, no part of it is [[open-source software|open source]]. However a copy of the kernel source is present in every RSX distribution, because it was used during the [[system generation]] process. The notable exception to this rule is Micro-RSX, which came with a pre-generated autoconfiguring binary kernel. Full sources was available as a separate product to those who already had a binary license, for reference purposes.

Ownership of RSX-11S, RSX-11M, RSX-11M Plus and Micro/RSX was transferred from Digital to [[Mentec PDP-11|Mentec Inc.]] in March 1994<ref>{{cite web| url=http://www.bitsavers.org/pdf/dec/pdp11/rsx11m_s/SPD/AV-QKPJA-TE_Notice_of_Copyright_Change_for_PDP-11_Software_Products_1995.pdf| title=Notice of Copyright Change for PDP-11 Software Products| author=Mentec Inc.| date=1995| access-date=15 November 2022}}</ref> as part of a broader agreement.<ref>{{cite web| url=https://groups.google.com/forum/#!topic/biz.digital.announce/mnNlxqdYTwo| title=Press release: Digital and Mentec announce PDP-11 Software Agreement| author=Digital Equipment Corporation| date=29 June 1994| access-date=11 December 2017}}</ref>
Mentec Inc. was the US subsidiary of [[Mentec PDP-11|Mentec Limited]], an Irish firm specializing in PDP-11 hardware and software support. In 2006 Mentec Inc. was declared bankrupt while Mentec Ltd. was acquired by Irish firm Calyx in December 2006.<ref>{{cite web| url=https://www.theregister.co.uk/2006/12/13/calyx_buys_mentec/| title=Calyx buys Mentec| author=Mentec Inc.| website=[[The Register]]| date=13 December 2006| access-date=11 December 2017}}</ref> The PDP-11 software, which was owned by Mentec Inc. was then bought by XX2247 LLC, which is the owner of the software today.{{Citation needed|date=November 2022}} It is unclear if new commercial licenses are possible to buy at this time. Hobbyists can run RSX-11M (version 4.3 or earlier) and RSX-11M Plus (version 3.0 or earlier) on the [[SIMH]] emulator thanks to a free license granted in May 1998 by Mentec Inc.<ref>{{cite web| url=https://www.eecis.udel.edu/~mader/delta/download/license.txt| title=Mentec Hobbyist license for PDP-11 operating systems| author=Mentec Inc.| date=May 1998| access-date=11 December 2017}}</ref>

Legal ownership of RSX-11A, RSX-11B, RSX-11C, RSX-11D, and IAS never changed hands; therefore it passed to [[Compaq]] when it acquired Digital in 1998<ref>{{cite web| url=https://www.cnet.com/news/compaq-to-buy-digital-for-9-6-billion/| title=Compaq to buy Digital for $9.6 billion| author=Michael Kanellos| date=26 January 1998| publisher=cnet.com| access-date=11 December 2017}}</ref> and then to [[Hewlett-Packard]] in 2002.<ref>{{cite web| url=https://www.cnet.com/news/hp-to-acquire-compaq-for-25-billion/| title=HP to acquire Compag for $25 billion| author=Michael Kanellos| date=10 March 2002| publisher=cnet.com| access-date=11 December 2017}}</ref> In late 2015 Hewlett-Packard split into two separate companies ([[HP Inc.]] and [[Hewlett Packard Enterprise]]),<ref>{{cite web| url=https://www.recode.net/2015/11/2/11620238/hewlett-packard-splits-in-two-today-now-what| title=Hewlett-Packard splits in two today, now what ?| author=Arik Hesseldahl| date=2 November 2015| publisher=recode.net| access-date=11 December 2017}}</ref> so the current owner cannot be firmly established.{{dubious|date=June 2020}} No new commercial licenses have been issued since at least October 1979 (RSX-11A, RSX-11B, RSX-11C)<ref>Products no longer appeared on Digital PDP-11 System Software Catalogue issued Oct. 1979: {{cite web| url=http://www.bitsavers.org/pdf/dec/pdp11/catalogs/AV-3468J-TC_SysSwCataOct79.pdf| title=PDP-11 System Software Component Catalogue| date=October 1979| publisher=Digital Equipment Corp.| access-date=11 December 2017}}</ref> or 1990 (IAS),<ref name="final_IAS" /> and none of these operating systems have ever been licensed for hobbyist use.