This document discusses some CMS commands available on z/VM.
NOTE: CMS is unavailable when your virtual machine is running a guest operating system such as Linux. CMS is itself an operating system. (This can be confusing at first.)
CMS is the "Conversational Monitor System", a single user operating system exclusive to the z/VM environment. (CMS cannot run without "CP", the z/VM hypervisor.)
CMS provides a very efficient interactive environment. For ZNETBOOT, CMS provides the essential functions needed to retrieve a Linux kernels and supporting files from the network, arrange them in proper order, and then direct the CP hypervisor to boot Linux.
You cannot issue CMS commands when running Linux. You cannot have Linux running when CMS is booted. They are distinct operating systems.
Whether running CMS or Linux, you still have CP, the Control Program. CP commands on z/VM are common between CMS and Linux. That is to say, the same CP commands available when you are running CMS are still available when you are running Linux, but invoking them is different. To confuse matters, CMS passes commands it does not recognize to CP. This is ostensibly for convenience, but has the unfortunate effect that many users do not know if a z/VM command is a CP command (also available to Linux) or a CMS command (not available in Linux).
Some common CMS commands follow.
znetboot is the central command of this project.
It attempts to download and boot Linux (or any operating system)
using a kernel and related files retrieved from the network.
znetboot takes an optional argument, the name of a configuration file.
If you wanted to boot Linux according to the clefonvm configuration
then you would enter
znetboot clefonvm
znetboot requires CMS but is not a standard CMS utility.
filelist is a standard CMS utility presenting a list of your files.
filelist is a full-screen utility, commandeering your 3270 session
and obviating the usual z/VM screen layout.
filelist can be abbreviated fl.
Within filelist, same as most CMS full-screen utilities,
<PF3> exits to the command prompt.
listfile is a standard CMS utility for listing files interactively.
It is the operational equivalent of the ls command in Unix nd Linux.
Files in CMS are multi-token. There is a filename and a filetype. There is also a filemode which combines a drive letter or directory letter with a numeric modifier. The letter is strictly related to where the disk or directory is accessed, sort of like where a filesystem is mounted in Linux and Unix. The number can affect the behavior of the system when handling the file. Discussion of filemode numbers is beyond the scope of this document.
listfile can be abbreviated list.
An example use of listfile is the listing of your ZNETBOOT files.
list * znetboot
or
list * znetboot a
Either form lists all files on your "A disk" with a filetype of ZNETBOOT.
XEDIT is the CMS text file editor.
xedit can be abbreviated x.
The details of using XEDIT are beyond the scope of this document,
but an example use of XEDIT is to modify your ZNETBOOT file.
Suppose you have a clefonvm configuration file for ZNETBOOT.
x clefonvm znetboot
This command will invoke the editor on your configuration file.
XEDIT is a full-screen text editor, so you may simply overtype
to make changes. XEDIT is a command oriented editor, so you would
save your changes with a save command, or save-and-exit with file.
rdrlist is a standard CMS utility presenting your "reader list".
The display of rdrlist is similar to that of filelist,
but the files it displays exist in spool space, not on disk.
z/VM spool space is vital to the operation of znetboot
and you may have "spool files" of interest which can be managed
from the rdrlist utility.
rdrlist can be abbreviated rl.
Within rdrlist, same as most CMS full-screen utilities,
<PF3> exits to the command prompt.
help provides helpful information as the verb implies.
CMS help is extensive, if daunting.
It is conceptually just like the Unix man command
but is a full-screen utility like filelist and rdrlist.
Within help, same as most CMS full-screen utilities,
<PF3> exits to the command prompt.