Editing OS/2 (section)

===Virtualization===
OS/2 has historically been more difficult to run in a virtual machine than most other legacy [[x86]] operating systems because of its extensive reliance on the full set of features of the x86 CPU; in particular, OS/2's use of [[protection ring|ring 2]] prevented it from running in early versions of [[VMware]].<ref>{{cite web|title=A Notice to OS/2 Users|author=The VMware Team|url=http://www.vmware.com/support/reference/common/guest_os2_exp.html|url-status=dead|archive-url=https://web.archive.org/web/20060420232220/http://www.vmware.com/support/reference/common/guest_os2_exp.html|archive-date=2006-04-20}}</ref> Newer versions of VMware provide official support for OS/2, specifically for eComStation.<ref>{{cite web|url=http://partnerweb.vmware.com/GOSIG/eComStation_2x.html|title=Guest Operating System Installation Guide - eComStation 2.x|date=2014|publisher=VMware|access-date=2022-01-13}}</ref>

[[VirtualPC]] from Microsoft (originally [[Connectix]]) has been able to run OS/2 without hardware virtualization support for many years. It also provided "additions" code which greatly improves host–guest OS interactions in OS/2. The additions are not provided with the current version of VirtualPC, but the version last included with a release may still be used with current releases. At one point, OS/2 was a supported host for VirtualPC in addition to a guest. Note that OS/2 runs only as a guest on those versions of VirtualPC that use virtualization (x86 based hosts) and not those doing full emulation (VirtualPC for Mac).

[[VirtualBox]] from [[Oracle Corporation]] (originally [[InnoTek]], later [[Sun Microsystems|Sun]]) supports OS/2 1.x, Warp 3 through 4.5, and eComStation as well as "Other OS/2" as guests. However, attempting to run OS/2 and eComStation can still be difficult, if not impossible, because of the strict requirements of VT-x/AMD-V hardware-enabled virtualization and only ACP2/MCP2 is reported to work in a reliable manner.<ref>{{cite web|title=VirtualBox Guest_OSes|author=VirtualBox| url=http://www.virtualbox.org/wiki/Guest_OSes}}</ref>

ArcaOS supports being run as a [[virtual machine]] guest inside [[VirtualBox]], [[VMware ESXi]] and [[VMWare Workstation]].<ref>{{cite web|url=https://www.arcanoae.com/wiki/arcaos/installation-planning/virtual-machine-configuration/|title=Virtual Machine Configuration|work=Arca Noae |access-date=2020-09-05}}</ref> It ships with VirtualBox Guest Additions, and driver improvements to improve performance as a guest operating system.<ref>{{cite web|url=https://www.arcanoae.com/wp-content/uploads/wiki/ArcaOS-changes.txt|title=ArcaOS 5.0 Changes|website=arcanoae.com|access-date=2020-09-04}}</ref>

The difficulties in efficiently running OS/2 have, at least once, created an opportunity for a new [[Platform virtualization|virtualization]] company. A large bank in [[Moscow]] needed a way to use OS/2 on newer hardware that OS/2 did not support. As virtualization software is an easy way around this, the company desired to run OS/2 under a [[hypervisor]]. Once it was determined that VMware was not a possibility, it hired a group of Russian software developers to write a host-based hypervisor that would officially support OS/2. Thus, the [[Parallels (company)|Parallels, Inc.]] company and their [[Parallels Workstation]] product was born.<ref>{{cite web|title=Breaking News—Parallels Joins the PC and Server Virtualization Fray|author=Timothy Prickett Morgan|url=http://www.itjungle.com/breaking/bn090705-story01.html|work=itjungle.com|url-status=dead|archive-url=https://web.archive.org/web/20070403063933/http://www.itjungle.com/breaking/bn090705-story01.html|archive-date=2007-04-03|access-date=2007-10-19}}</ref>