Editing VM (operating system) (section)

== OpenEdition extensions ==

Starting with VM/ESA Version 2, IBM introduced the chargeable optional feature ''OpenEdition for VM/ESA Shell and Utilities Feature'',<ref>{{cite web | title = Availability: VM/ESA Version 2 Release 1.0 with OpenEdition for VM/ESA | id = 295-240 | date = June 12, 1995 | url = https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/0/897/ENUS295-240/index.html | series = Announcement Letters | publisher = IBM | access-date = October 28, 2021 | archive-date = October 28, 2021 | archive-url = https://web.archive.org/web/20211028222454/https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/0/897/ENUS295-240/index.html }}</ref> which provides POSIX compatibility for CMS. The stand-out feature was a UNIX shell for CMS. The C compiler for this UNIX environment is provided by either C/370 or C for VM/ESA. Neither the CMS filesystem nor the standard VM Shared File System has any support for UNIX-style files and paths; instead, the Byte File System is used. Once a BFS extent is created in an SFS file pool, the user can mount it using the <code>OPENVM MOUNT /../VMBFS:fileservername:filepoolname /path/to/mount/point</code>. The user must also mount the root filesystem, done with <code>OPENVM MOUNT /../VMBFS:VMSYS:ROOT/ /</code>, a shell can then be started with <code>OPENVM SHELL</code>. Unlike the normal SFS, access to BFS filesystems is controlled by POSIX permissions (with [[chmod]] and [[chown]]).

Starting with z/VM Version 3, IBM integrated OpenEdition into z/VM<ref>{{cite web | title = z/VM V3R1 Enabled for 64-bit Architecture | id = 200-358 | date = October 3, 2000 | url = https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/8/897/ENUS200-358/index.html | series = Announcement Letters | publisher = [[IBM]] | access-date = January 31, 2022 | archive-date = December 17, 2021 | archive-url = https://web.archive.org/web/20211217151307/https://www.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/8/897/ENUS200-358/index.html | url-status = live }}</ref> and renamed it OpenExtensions. OpenEdition and OpenExtensions provide POSIX.2 compliance to CMS.<ref>{{Cite web |date=2020-08-21 |title=IBM z/VM: OpenExtensions POSIX Conformance Document (GC24-6298-01) |url=https://www.ibm.com/servers/resourcelink/svc0302a.nsf/pages/zVMV7R2gc246298?OpenDocument |access-date=2022-07-31 |website=www.ibm.com |language=en-US |archive-date=February 28, 2024 |archive-url=https://web.archive.org/web/20240228073121/https://www-40.ibm.com/servers/resourcelink/svc0302a.nsf/pages/zVMV7R2gc246298?OpenDocument |url-status=live }}</ref> Programs compiled to run under the OpenExtensions shell are stored in the same format as standard CMS executable modules. Visual editors, such as [[Vi (text editor)|vi]] are unavailable, as 3270 terminals are not capable. Users can use [[Ed (text editor)|ed]] or [[XEDIT]] instead of vi.