About the Common Tape System

Common Tape System › About the Common Tape System

About the Common Tape System

The Common Tape System (CTS) is a component distributed with CA TLMS for the purpose of creating a single image and common interfaces for CA z/OS tape management products (CA TLMS and CA 1). This allows other CA products, client programs, and other vendor products to have a single set of interfaces to CA tape solutions. It consists of utility programs, macros, and a subtasking address space.

This section deals with the subtasking address space. The CTS address space consists of a main task, a command task, a dump task, and service programs. An optional external (gummed) label task is part of CTS but is described in another section. TLMS is not part of CTS but has been made CTS compliant. CTS replaces the functions provided by OMS in prior versions.

CTSMAIN is the main task of the CTS address space. It maintains the other task as subtasks and anchors the service programs. The service programs provide for inter-task communications, logging messages, and snap dumps. Each subtask has a 1 to 4 character TASKID that is unique within the address space. When CTSMAIN attaches a subtask, it creates a control block (CTSB) which contains the TASKID, control data, and parameters to pass to the subtask. The address of the CTSB is passed to the subtask. A CTS compliant task, communicates with other CTS tasks on a peer-to-peer basis through their CTSBs. If a task abends, CTSMAIN will restart it as many times as was defined in its CTSB.

There are several tasks which are predefined to CTSMAIN. All other tasks must be defined through a SET TASK(....) command before they can be started with a START command. CMD, DUMP, API, DBS, and LAB are the predefined task IDs. CMD and DUMP are discussed below, and LAB in a later section. API and DBS are reserved for future services.

CTSCMD is the command processing task for the CTS address space. It is the only task that communicates with CTSMAIN. Its TASKID is CMD. CMD is predefined to CTSMAIN and is automatically started by CTSMAIN. The function of CMD is to receive commands from multiple sources, verify, and execute them. CTSCMD gets commands from five sources. First a command can be entered in the PARM= field of the EXEC JCL statement; it is processed first. Next CTSCMD reads the command from the CTSSYSIN DD JCL statement. Usually this points to the CAI.CTAPOPTN member CTSSTART. After that, commands are processed from any of the remaining sources. Commands can be sent to CMD from any other CTS task. Commands may come from a z/OS modify for CTS (f CTS, DISPLAY ACTIVE). A command can be entered in reply to the optional outstanding WTOR. CTSCMD treats commands from all sources equally.

CTSDMP is the other predefined and automatically started CTS task. Its TASKID is DUMP. Its function is to automatically copy dumps to a SYSOUT so that they are available without having to stop the CTS address space. After CTSDMP is started, it checks for the presence of a SYSUDUMP or SYSABEND allocated to DASD. If the DD is missing or is for a SYSOUT, the DUMP task terminates with an RC=0 since it is not needed to unspool dumps. If there is a dump data set, CTSDMP attempts to copy a dump from it and notify the console when it is complete. Because the dump data set is defined as MOD, more dumps may be added while it is being copied by dump. CTSDMP will empty the data set when it completes.

Important! Ensure that the dump data set has the proper attributes for a dump data set and that it has been written to before CTSDMP is started, if not an abend will occur.

CTSMSG is a service program that allows messages from multiple tasks in the CTS address space to log messages to a single log. It will copy that log to SYSOUT when the SPINOFF LOG command is issued. No response is given.

CTSSNP is a service program that allows snap dump from multiple tasks in the CTS address space to be sent to a single file. It will copy that file to SYSOUT when the SPINOFF SNAP command is issued. No response is given.

All other CTS tasks must be defined to CTS by SET commands and then attached through the START command. The CTS address space only provides a generic multi-tasking environment and the basic messages and dump service.

The purpose of the Common Tape System (CTS) is to provide a set of interfaces to all CA Tape Management products. CTS consists of a started task, utilities, and interface programs. CTS is started from SYS1.PROCLIB(CTS). During startup it reads commands from the CTSSYSIN DD, which is CAI.CTAPOPTN (CTSSTART) by default. This section contains a discussion of those commands.

Important! Ensure that the dump data set has the proper attributes for a dump data set and that it has been written to before CTSDMP is started, if not an abend will occur.