OPENVM SHELL. 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 and renamed it OpenExtensions. OpenEdition and OpenExtensions provide POSIX.2 compliance to CMS. Programs compiled to run under the OpenExtensions shell are stored in the same format as standard CMS executable modules. Visual editors, such as vi are unavailable, as 3270 terminals are not capable. Users can use ed or XEDIT instead of vi. VM mascot In the early 1980s, the VM group within SHARE (the IBM user group) sought a mascot or logo for the community to adopt. This was in part a response to IBM's MVS users selecting the turkey as a mascot (chosen, according to legend, by the MVS Performance Group in the early days of MVS, when its performance was a sore topic). In 1983, the teddy bear became VM's de facto mascot at SHARE 60, when teddy bear stickers were attached to the nametags of "cuddlier oldtimers" to flag them for newcomers as "friendly if approached". The bears were a hit and soon appeared widely. Bears were awarded to inductees of the "Order of the Knights of VM", individuals who made "useful contributions" to the community. Criticism While VM was relatively light-weight (when compared to its counterparts, such as MVS), VM was somewhat unstable in its early days. It was considered quite a feat to keep a VM/370 system up for more than a week. Users also criticized the CMS file system, noting that other operating systems in the mid-1980s had directories, symbolic links, and other key features; CMS had none of these until 1988 when VM/SP release 6 came out, which introduced the Shared File System and alleviated these issues. Some users also noted that VM OpenEdition was somewhat "unnecessary." Notes See also Time-sharing system evolution References External links VM sources Bob DuCharme, Operating Systems Handbook, Part 5: VM/CMS– a fairly detailed user's guide to VM/CMS E. C. Hendricks and T. C. Hartmann, "Evolution of a Virtual Machine Subsystem", IBM Systems Journal Vol. 18, pp. 111–142 (1979)– RSCS design and implementation IBM Corporation, IBM Virtual Machine Facility/370 Introduction, GC20-1800, (1972)– the original manual Other resources IBM Redbooks Publication – z/VM textbook IBM: z/VM portal IBM: z/VM manuals VM/PC documentation on bitsavers Time-sharing operating systems IBM mainframe operating systems Virtualization software Assembly language software IBM ESA/390 operating