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z/VM Module 2: Conversational Monitor System (CMS). Objectives. List z/VM’s base components and describe how they work together Describe CMS and the tasks it can accomplish State why CMS Pipelines are an important feature of z/VM Describe CMS Application Multitasking
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Objectives • List z/VM’s base components and describe how they work together • Describe CMS and the tasks it can accomplish • State why CMS Pipelines are an important feature of z/VM • Describe CMS Application Multitasking • Describe the XEDIT environment and its purpose
Objectives continued • Describe the three important application environments that CMS supports: • Callable Service Library (CSL) • OpenExtensions • Reusable Server Kernel • Show how to find and use the Help Facility • Explain Shared File System (SFS) setup and configuration • Explain how syntax diagrams are used • List and describe the most important and useful CMS commands
Introducing z/VM’s Base Components • Conversational Monitor System (CMS) • An end-user interface for running user programs • Control Program (CP) • A component that manages the resources of a single system to make it appear that multiple computing systems exist • REXX/VM • A programming language that allows you to write customized application programs and command procedures • Group Control System (GCS) • A virtual machine supervisor that provides multitasking services
Introducing z/VM’s Base Components continued • Transparent Services Access Facility (TSAF) • APPC/VM VTAM Support (AVS) • Virtual Machine Serviceability Enhancements Staged/Extended (VMSES/E) • Dump Viewing Facility
What is CMS? • Conversational Monitor System is an operating system environment itself • Over time CMS became a part of VM • CMS is a single user operating system, which makes it possible to: • Create and maintain files • Write and execute application programs • CMS communicates with users through the console
CMS Tasks With CMS, you can: • Write, test, and debug application programs for use on CMS or guest systems • Run application programs developed on CMS or guest systems • Create and edit data files • Process jobs in batch mode • Share data between CMS and guest systems • Communicate with other system users
CMS Pipelines • Provide a rich and efficient set of functions that can be used to solve large problems by breaking them up into smaller programs • Smaller programs are called stages • Stages: • Read data • Filter and refine data • Combine multiple data items
Pipeline Example pipe < profile exec | count lines | console • This command executes the number of lines contained within your PROFILE EXEC file.
CMS Application Multitasking • An application can be divided into multiple units of execution, called threads. • Threads have the ability to run on multiple CPUs at the same time • Multitasking facilities allow applications to harness the power of the underlying multiprocessor complex to achieve high performance.
OpenExtensions • OpenExtensions provides open systems support in two ways: • OpenExtensions Services • OpenExtensions Shell and Utilities • OpenExtensions Services include: • POSIX.1—System Interfaces • POSIX.1a—Extensions to POSIX.1 • POSIX.1c—Threads
OpenExtensions – Invocation • Invocation from REXX Procedures example • OPENVM is a z/VM subcommand environment • OPENVM makes invocation of callable services look like other requests for host functions • The OPENVM language binding file defines REXX variables used by the OpenExtensions services. You include the file using the APILOAD function.
Reusable Server Kernel • Enables vendors and application programmers to write multithreaded server programs • The server kernel is the starting point for a server program • To construct a server program you need: • A text library of routines • A macro library of function prototypes • Constant definitions • These entities are supplied by the Reusable Server Kernel
Additional RSK Help Areas • Connectivity • DASD I/O • Authorization • Memory management • Runtime environment • Worker machines • Configuration and operation
The Batch Facility • Can take over both short and long processing jobs for you • Frees up your time to continue working at your terminal • Two examples: • Have the facility format text and send it to the printer, instead of doing it yourself • Have large jobs run throughout the night to take advantage of lower computing costs
How the VM Batch Facility Works • The process starts when you submit a job to the VM Batch Facility • The monitor virtual machine receives your job and holds it until it can start • A task virtual machine runs your job • The monitor machine periodically checks your job while it runs • Your commands can retrieve the status of a job, change how and when it is to run, and cancel a job • When your job is completed, the task machine logs off and is ready for another job
z/VM Help Facility • CMS Help Facility provide assistance for: • Tasks • Commands and options • Subcommands • REXX statements • Callable routines • Pipeline stages • Assembler language macros • Messages
Shared File System (SFS) • Files are stored in file pools • A user can be given an amount of file space in a pool • The files in a file space are organized in directories • A file can be placed in more than one directory
Shared File System (SFS) continued • Users can grant each other authorities for files or directories • Multiple users can have concurrent access to the same file or directory • Locks on files and directories ensure data integrity among multiple users • You can share files and directories with users on other systems
Syntax Diagrams (basics) • Read syntax diagrams from left to right and from top to bottom • This side module shows you descriptions and examples
ACCESS – Usage Notes • Using the ACCESS command with a directory ID or a device number • With and without a file pool • Using the ACCESS command with a directory ID • Determining status by ownership • Using the ACCESS command with a virtual device number • Access can create a file directory in your virtual machine when one is not present
RELEASE • The RELEASE Command is used to free an accessed disk that was previously accessed with the ACCESS Command. • Example: • release 0293
RELEASE • If you want to release and detach the 498 disk that is accessed as your file mode b, then issue: • release 498 (det OR -- release b (det • To just release the disk currently accessed as file mode c, issue: • release c
FORMAT – Usage Notes • Examples of RECOMP and LABEL: • format 192 b (recomp) • format 193 c (label) • Formatting a disk requires heavy processor utilization, so can be slow and affect performance • Choose the appropriate block size to optimize: • space utilization • performance • Automatic formatting is possible on the 192 disk
Conclusion • CMS – Conversational Monitor System • Is a operating system that runs within z/VM • CMS tasks include writing, testing, and debugging application programs to be used by CMS or z/VM guest systems • CMS runs the full-screen editing facility called XEDIT • The CMS help facility is a CMS Command that can be accessed when help is needed by entering: • help cms
Glossary Conversational Monitor System (CMS)- A component of z/VM that runs in a virtual machine and provides both the interactive z/VM end-user interface and the general z/VM application programming interface. CMS runs only under the control of the z/VM Control Program (CP). CMS Pipelines- CMS job control product for z/VM that enables complex tasks to be specified and executed. CMS Pipelines has three parts – a command parser, a library of built-in programs, and a dispatcher. Callable Services Library-A package of CMS routines that can be stored as an entity and made available to a high-level language, REXX, or an assembler program.
Glossary File pool-A collection of minidisks managed by a file pool server. It contains user files and directories and associated control information. The files and directories for many users can be contained in a single file pool. Group Control System (GCS)- A component of z/VM, consisting of a named saved system that the user can IPL and run in a virtual machine. It provides simulated MVS services and unique supervisor services to help support a native SNA network. Initial Program Load (IPL)- The process of loading an operating system into a machine OpenExtensions Services- The VM implementation of three POSIX standards
Glossary OpenExtensions Shell and Utilities- provides application development tools and an interactive environment in support of the POSIX application environment. REXX/VM- (REstructed eXtended eXecutor programming language) processes English-like commands. XEDIT- A full-screen editing facility that runs under CMS.
References • CMS Command and Utility Reference. Manual Number: SC24-6010-02. Third Edition (May 2002). • CMS User’s Guide. Manual Number: SC24-6009-00. First Edition (July 2001).