Editing ICL VME (section)

===Unix and open systems interoperability===

ICL had originally announced a hosted Unix facility for VME in 1985, with availability and support for strategic applications to arrive within eighteen months.<ref name="computerworld19851014_icl">{{ cite magazine | url=https://archive.org/details/sim_computerworld_1985-10-14_19_41/page/n31/mode/2up | title=ICL banks on open systems strategy | magazine=Computerworld | date=14 October 1985 | access-date=3 June 2024 | pages=30–31 }}</ref> This facility, supporting [[UNIX System V#SVR1|SVR1]], was reportedly in "field trials" and was to be upgraded to [[UNIX System V#SVR2|SVR2]] prior to a general release in the summer of 1987.<ref name="unigramx19860927_icl">{{ cite news | url=https://archive.org/details/unigram_x_1986_0034_0058/page/26/mode/1up | title=Unix under VME Now out on Field Trials | work=Unigram/X | date=27 September 1986 | access-date=22 July 2024 | pages=4 }}</ref> Limited availability was then announced to existing VME customers, with others being guided towards ICL's Clan range of Unix departmental systems.<ref name="unigramx19870627_icl">{{ cite news | url=https://archive.org/details/UnigramX1987109-159/page/n150/mode/1up | title=ICL Sets Unix under VME for September | work=Unigram/X | date=27 June 1987 | access-date=22 July 2024 | pages=1 }}</ref>

In October 1987, ICL made the SV221 release of VME available with support for running SVR2 as a VME Unix System guest.<ref name="unigramx19871003_icl">{{ cite news | url=https://archive.org/details/UnigramX1987109-159/page/n229/mode/1up | title=ICL Guests Unix under New VME Release, Adds Cut-Down 39/80 Mainframe Models | work=Unigram/X | date=3 October 1987 | access-date=22 July 2024 | pages=2 }}</ref> This implementation, described as an "unmarketed" product also known as VNS, informed the design of VME/X, a largely new implementation that was itself released in 1991 and recognised as XPG3 compliant, with XPG4 base 1 compliance following in 1992.<ref name="icl199305_coates"/>{{rp|pages=489–490}} ICL's OpenVME promotional material noted that VME had been the first non-Unix operating system to gain XPG3 compliance, and the first operating system of any kind to gain XPG4 base compliance.<ref name="iclopenvme1994">{{ cite book | url=http://www.1000bit.it/ad/bro/icl/icl-openvme-thewayforward.pdf | title=OpenVME the way forward | publisher=International Computers Limited | date=1994 | access-date=6 December 2024 | pages=2 }}</ref>

In 1995, ICL added support for the [[Internet protocol suite]] in the form of its UNIX Interworking Option for OpenVME, featuring implementations of TCP/IP, UDP/IP and support for the [[File Transfer Protocol]], [[Telnet]] and [[Network File System]] (NFS) protocols. The NFS functionality included a server that enabled portions of the OpenVME filestore to be served to NFS clients, and the Telnet functionality allowed users on an OpenVME system to access Unix hosts, also supporting the provision of a login facility on OpenVME for remote users using the protocol. Alongside the [[Berkeley sockets]] programming interface, already widely used by Unix applications, the product also offered the [[X/Open Transport Interface]] for protocol independence and to support the [[OSI protocols]] customarily used by VME software.<ref name="icltcp1995">{{ cite book | url=http://www.1000bit.it/ad/bro/icl/tcpovme.pdf | title=OpenVME UNIX Interworking Option | publisher=International Computers Limited | date=1995 | access-date=7 December 2024 | pages=2–3 }}</ref>