Specifications

58 IBM System z Personal Development Tool: Volume 3 Additional Topics
4.3 CMS
CMS is the Conversational Monitor System. It is a small, single-user operating system. Every
user running CMS is running a separate CMS in a separate virtual machine.
4
CMS is a
special-case operating system that runs only under z/VM. z/VM administration is done
through CMS. The READY prompts you see on the windows are indicators that CMS is
running in a virtual machine.
It is possible to use CMS for application development and as a base for user applications.
This usage is not described here. Nevertheless, basic CMS usage is required for almost any
administrative activity for a z/VM system.
Once z/VM is IPLed and you log on to a userid, you need to IPL CMS within that userid
(assuming you want to use CMS). This CMS IPL can be automatic (when you log on to the
userid) or it can be done manually with an IPL CMS or IPL 190 command. The automatic IPL
is enabled by a line in the z/VM directory entry for the userid. A RUNNING indicator in the
lower right corner of the 3270 panel is an indicator that CMS is running.
Each CMS user has his/her own copy of CMS; it is a single-user operating system. (In
practice, there is a single copy of CMS in shared virtual memory.)
CMS has a large set of functions and commands. The basic z/VM Control Program (CP) also
has a large set of commands. In general, both sets of commands can be entered on the CMS
command line. In a few cases, CP commands must be prefixed by the letters CP or #CP
followed by a space and then the command.
When you log onto z/VM, your virtual machine is in one of three environments:
򐂰 It has IPLed CMS and you may enter CMS and CP commands.
򐂰 It has IPLed another operating system, such as z/OS, and is under the control of that
operating system.
򐂰 It has not IPLed anything. Only CP commands may be entered.
When using CMS (or interacting directly with CP, if CMS has not been started) the 3270
session is in a pseudo-3215 mode. This is a typewriter-like interface, with a command line at
the bottom of the panel. Some CMS functions, such as XEDIT, provide a full-panel interface
similar to IPSF.
4.3.1 User MAINT
z/VM has a predefined userid, MAINT (password MAINT). Most basic z/VM administration is
performed while using this userid and working through CMS.
5
Logging onto MAINT should
produce the window shown in Figure 4-4 on page 59.
4
Actually, only one copy of CMS exists. It uses shared virtual memory so that it appears to exist in the virtual
memory of each user who IPLs CMS.
5
Starting with z/VM 6.2 some administration is done through userid MAINT620.