z/VM Version 7 Release 1 Group Control System IBM SC24-6289-00 Note: Before you use this information and the product it supports, read the information in “Notices” on page 543. This edition applies to version 7, release 1, modification 0 of IBM® z/VM (product number 5741-A09) and to all subsequent releases and modifications until otherwise indicated in new editions. Last updated: 2018-09-06 © Copyright International Business Machines Corporation 2001, 2018. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents List of Figures....................................................................................................... ix List of Tables........................................................................................................ xi About This Document..........................................................................................xiii Intended Audience.................................................................................................................................... xiii Syntax, Message, and Response Conventions..........................................................................................xiii Where to Find More Information...............................................................................................................xvi Links to Other Documents and Websites............................................................................................ xvi How to Send Your Comments to IBM................................................................... xvii Summary of Changes for z/VM Group Control System.........................................xviii SC24-6289-00, z/VM Version 7 Release 1............................................................................................. xviii SC24-6196-03, z/VM Version 6 Release 4............................................................................................. xviii Chapter 1. Group Control System Overview............................................................ 1 What GCS Is................................................................................................................................................. 1 What Applications GCS Supports................................................................................................................ 2 How GCS Relates to CMS............................................................................................................................. 3 Virtual Machine Groups................................................................................................................................4 Building the Group..................................................................................................................................4 Joining a Virtual Machine Group............................................................................................................ 5 Implementation of a GCS Group............................................................................................................5 GCS Recovery Machine...........................................................................................................................5 GCS Group Communication....................................................................................................................6 Communicating Between Machines in a Group.....................................................................................7 Authorization................................................................................................................................................8 Controlling Access to the GCS Supervisor............................................................................................. 9 Controlling Access to Supervisor State..................................................................................................9 Controlling Access to CP Commands.....................................................................................................9 GCS Storage............................................................................................................................................... 10 Overview of GCS Storage Layout..........................................................................................................11 Private Storage..................................................................................................................................... 12 Common Storage..................................................................................................................................13 Whole Picture at a Glance..........................................................................................................................13 GCS Scenario..............................................................................................................................................14 Establish the Path Between System and Console...............................................................................14 GCS Task Management.............................................................................................................................. 18 Adding and Discarding Tasks............................................................................................................... 18 Dispatching Tasks.................................................................................................................................19 GCS System Tasks................................................................................................................................ 20 Task Dispatching and Multi-tasking Services...................................................................................... 20 Coordinating Dependent Tasks............................................................................................................21 Coordinating Shared Resources...........................................................................................................22 Terminating Tasks.................................................................................................................................23 Abend Processing.................................................................................................................................24 General I/O (GENIO) Facility..................................................................................................................... 24 GCS Real I/O.........................................................................................................................................25 Chapter 2. Planning for GCS.................................................................................27 Planning GCS Storage Layout.................................................................................................................... 27 Calculating Storage Requirements............................................................................................................27 iii Preparing to Build Other Saved Segments................................................................................................29 Shared Segments Recognized by GCS.................................................................................................30 Private Segments for Applications.......................................................................................................30 Making VSAM Available to GCS................................................................................................................. 30 Authorizing Access to Supervisor State.................................................................................................... 30 Authorizing Access to GCS.........................................................................................................................31 Authorizing Commands for Virtual Machines............................................................................................31 Authorizing Machines for Real I/O.............................................................................................................31 Using AUTOLOG Functions........................................................................................................................ 31 Using a PROFILE GCS File..........................................................................................................................32 Preparing CP Directory Entries.................................................................................................................. 32 Operation................................................................................................................................................... 32 Initializing GCS (How to Join a Group).................................................................................................32 Starting and Stopping Programs.......................................................................................................... 33 Replying to Messages...........................................................................................................................34 Querying Information...........................................................................................................................34 Chapter 3. GCS Programming and Command Processing.......................................37 Linkage Registers.......................................................................................................................................37