Why does the startup of CAMASTER require an IPL?

Products

• COMMON SERVICES FOR Z/OS
• 90S SERVICES
• Common Services

Issue/Introduction

Customers have asked why the startup of CAMASTER requires an IPL.  Requests have been made to allow CAMASTER to start independently as a stated task.  

 

 

Environment

COMMON SERVICES 15.0 - z/OS supported releases - 

Cause

Question as to why does the startup of CAMASTER require an IPL?  

Resolution

Just as IBM requires *MASTER* GRS, CONSOLE, ALLOCAS, etc for their Operating System infrastructure, CAMASTER is needed for the Broadcom Mainframe framework.  

Common Services for z/OS provides components for other Mainframe Solutions to function correctly.  Additionally, CAMaster is required for the startup and operation of other Common Services for z/OS components.

An IPL is necessary because CA Master operates as a system address space; it cannot be started as a SUBSYS under IEFSSN.  CA MASTER is designed to provide services to all Broadcom products including the Mainframe Security Products ACF2 and Top Secret.  Because these security products initialize at a point in the IPL timeline before IEFSNNxx is processed, it is not possible to establish the CA MASTER services using the subsystem.  Furthermore, there are many products that can initialize as z/OS subsystems.  The functions supplied by the  CAMASTER must be in place before these products or components can be initialized successfully.

One design consideration for creating a permanent CA MASTER address space is the exploitation of program call (PC) routines.  This eliminates the necessity of a Broadcom product to define user SVC numbers since there are a limited number of choices available to use as an SVC number.  Additionally, the use of a user SVC number typically requires installation specifications necessary to identify a specific SVC for a product either in the product's configuration options or in the IEASVCxx member of PARMLIB.  Exploitation of PC routines eliminates both the need for installation configuration tasks as well as the constraints presented by the limited SVC numbers.  

As PC routines are bound to active, non-swappable address spaces by architecture, the need for the permanent CAMASTER system address space is a requirement.  For this reason, once CAMASTER has successfully initialized, it enters a wait.  No other task mod code executes in the CAMASTER address space as the home ASID after the wait.  This avoids any scenario that might cause a failure.  At this point, the CAMASTER address space is more or less an anchor for other Common Services components and/or Broadcom Solutions.

For successful CAMASTER initialization, the following Common Services libraries must be APF Authorized and Linklisted:

          APF                                             LINKLIST
    cai.CAW0LINK                               cai.CAW0LINK
    cai.CAW0PLD                                cai.CAW0PLD
    cai.CAW0LOAD