The stack is indeed a CMS concept and CP is thus not able to read from it.
A little bit more explanation may be needed for others (especially those working on systems where an External Security Manager (ESM) is active, such as RACF/VM) :
If no ESM on the system
Link passwords are defined on the MDISK cards in the CP directory. If the password is ALL then it means everybody can link without providing a password on the LINK command (public access). If no password is defined at all, then it is impossible to link to the disk. In the other cases, the user has to provide the password specified in the CP directory.
At system generation, it is possible to specify that passwords must be suppressed when invoking the LINK command (Passwords_on_Commands Link Yes in the SYSTEM CONFIG file). Suppression here means that the user is not allowed to specify the password on the LINK command, but has to wait for the Enter password: prompt issued by CP (resulting in a CP READ status). The password can only be provided from that moment. CP has set the screen attribute of the command line to non-display in order to hide the password. This is a security option provided by the system.
If password suppression is activate, it remains possible to specify the password on the LINK command when the command is issued from programs or procedures, provided the command is issued via a DIAGnose instruction, the REXX DIAG() function, or the CMS macro CMSCALL with a calltyp=eplist or function (assembler program).
When address command is specified, then this calltyp method is used. However, if address CMS is specified (or implied), then the calltyp is such that the command seems to be issued from the terminal rather than from a program or subroutine. Consequently, the password suppression becomes active, and the password can no longer be specified as a parameter of the LINK (or LOGON) command.
With an ESM installed
Then the External Security Manager takes over complete control and passwords specified in the CP Directory are normally ignored.
The concept of ESM's normally is that a security administrator defines the set of users allowed to access certain resources (such as minidisks). Once a user is granted access, a password is not required.
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