Converting to DFSMSrmm from CA-1

8 Converting to DFSMSrmm from CA-1

When multiple systems exist, then they can share the same control data set. The

control data set cannot be a SYS1 data set if the control data set is to be shared.

Figure 1-4 shows the structure in this environment.

Figure 1-4 DFSMSrmm in a multisystem environment

When multiple systems share one CDS, you can use Global Resource

Serialization (GRS) resource definition to solve the possible contention

problems. Refer to “GRSRNLxx (optional) - Global resource serialization

resourcename list” on page 80 for details on how to customize GRS reserve and

release actions for DFSMSrmm.

1.1.3 What are the DFSMSrmm interfaces?

DFSMSrmm interacts with different system and non-system components to

perform the tape management functions. We introduce three different types of

interfaces: software interfaces, user interfaces, and programming interfaces.

Software interfaces are those interfaces between DFSMSrmm and some system

components or activities, such as allocation, open, close, and end of volume

events (OCE); and between DFSMSrmm and other software components, such

as DFSMSdfp, DFSMShsm, DFSMSdss, RACF, catalog, and OAM.

User interfaces are those that allow the communication between DFSMSrmm

and the end user. These user interfaces are the Interactive System Productivity

Facility (ISPF) dialogs and TSO commands.

Control

Data Set

z/OS

RMM

Address

Space

USER

Address

Space

S

S

I

PARMLIB

EDGRMMxx

z/OS

RMM

Address

Space

USER

Address

Space

S

S

I

PARMLIB

EDGRMMxx

Locking / Serialization

GRS

Control Data Set

Chapter 1. Introduction 9

Finally, the programming interfaces are those that allow the communication

between DFSMSrmm and user applications, or programs, for being able to get

information from DFSMSrmm, or to provide information to DFSMSrmm.

Software interfaces

In Figure 1-5, you can see a general view of what we consider the main

DFSMSrmm software interfaces. Using these interfaces, DFSMSrmm either

provides support to other users or request services from them. For detailed

information about this topic, refer to DFSMSrmm Implementation and

Customization Guide, SC26-7405.

Figure 1-5 Interfaces between DFSMSrmm and other software components

Now we describe what kind of information is exchanged between DFSMSrmm,

and each of the software interfaces and the activities performed:

 Allocation

At allocation time, DFSMSrmm intercepts the mount message, assigns a

scratch pool, and finds the rack where the volume resides; after that it

modifies the mount message to finish the response to this request.

 Open/close/end of volume interface (OCE)

DFSMSdfp provides tape exits for vendor or customer use; DFSMSrmm has

the capabilities to work with these exits to manage the open, close, and end of

volume event of tape. When such events happen, DFSMSrmm will:

Catalog

RACF

OAM

OCE

DFP

Object

Access

Method

Resource

Access

Control

Facility

Open /

Close /

End of Volume

Hierarchical

Storage

Manager

DSS

Allocation

Data

Facility

Product

Data Set Services

RMM

TSM

HSM

Tivoli

Storage

Manager

10 Converting to DFSMSrmm from CA-1

– Validate the mounted tapes.

– Store information in the CDS for volume and data sets if authorized.

– Return block-ID for high speed locate.

– Reject the volume if:

• A wrong volume is mounted for a specific volume request.

• A private volume is mounted in response to scratch request.

• An attempt is made to read a scratch volume.

• An attempt is made to overwrite a data set and the data set name does

not match.

• An attempt is made to use a specific scratch volume.

• The first file of the volume does not match what DFSMSrmm has

recorded.

• An attempt is made to read or write a volume using non-standard

labels.

• Unauthorized functions are used, such as bypass label processing,

write label, and so on.

 DFSMSdfp interface

DFSMSrmm provides EDGMSGEX exit as an interface to DFSMSdfp.

DFSMSrmm uses the IGXMSGEX exit, the MSGDISP installation exit of

DFSMSdfp, to call EDGMSGEX to retrieve DFSMSrmm information to update

tape drive displays and control the use of cartridge loaders.

For system-managed tapes, when the volume is open or closed or an

end-of-volume event occurs, the SMS ACS routines determine the volume

information.

For non-system-managed tapes, DFSMSrmm calls SMS ACS routines to get

information about the storage group for volumes and the management class

for data sets.

Figure 1-6 shows you the differences between these allocations.