The DBS function

This topic describes the functions provided by the Component Drive Booking Services.

The Drive Booking Services Component

BMC ThruPut Manager offers a Component that is installed on top of the BMC ThruPut Manager Base Product. The Component is named “Drive Booking Services”, or DBS for short. It provides two related but distinct services:

The management of jobs that require tape drives, real or virtual. The drives that are managed represent all the devices that are available to batch processing in a given JESplex.
The subdividing of the available tape drives into Work Groups to satisfy the requirements of different types of work, for example production versus non-production.

This section introduces the different functions provided with this package.

Functions Provided With DBS

This Component includes the following additional functions to support DBS:

DAL/JAL extensions.
JECL Service Extensions.
Operator commands.
TMISPF displays and dialog.
Initialization statement changes.

DAL and JAL for DBS

DBS supports the JAL Action statement DBS SET, allowing you to set the Work Group and Priority for a job. The DBS HOLD statement lets you specify that a job should be held rather than failed if it requests more device than are available in the ACTIVE Configuration.

If Installation Pools are used, the DAL Action statement DBS ASSIGN lets you indicate that a device belongs to a particular Installation Pool.

JAL Descriptors allow you to display in a message the DBS settings for a job.

For details and syntax descriptions, refer to the DAL-Reference-Guide and the JAL-Reference-guide.

JECL for DBS

BMC ThruPut Manager’s Job Analyzer cannot determine the correct counts for tape devices needed by jobs that use dynamic allocation for tapes. Also, the Job Analyzer does not examine STCs. You can, however, still have DBS manage the drives for STCs and jobs that use dynamic allocation. Simply add //*+DBS RESERVE JECL statements describing the requirements for each affected step.

For example:

//*+DBS RESERVE IBM->AUTOMATED->ATLDS1->3480S->3480=2This JECL statement allows DBS to maintain accurate counts for tape device usage.

You can also use JECL to specify the Work Group and/or DBS Priority for a job or STC by using the //*+DBS SET JECL statement:

//*+DBS SET WORKGROUP=SPECIAL,PRIORITY=HIGHFor details and syntax descriptions of these statements, refer to the System Base Product: Programming Guide.

Operator Commands for DBS

Operator commands allow you to:

Verify a DBS Configuration (DBS VERIFY).
Re-evaluate the ACTIVE Configuration if your I/O EDT changes (DBS REEVALUATE).
Activate Policies (DBS ACTIVATE).
Alter the DBS priority for a job (DBS ALTER).
Display the current status of DBS (DBS DISPLAY).
Change the DBS status of a DBS-managed device (DBS SET).

For details and syntax descriptions, refer to the Command-Reference-guide.

TMISPF dialog boxs and Displays

DBS uses dialog boxs in TMISPF to create and manage the Configuration and Policies. (For information about TMISPF, see the System Base Product: Programming Guide.)

TMISPF also displays information about the jobs and Drive Pools managed by DBS. Before using them, you should be familiar with some conventions.

Expanding and Collapsing Branches

Some windows use a display in the form of a tree structure. Lower levels can be expanded and collapsed. A plus sign (+) indicates that the branch is collapsed, and a minus sign (-) indicates that the branch is expanded. You expand or collapse branches by placing the cursor within the Pool name and pressing Enter. You will see this tree structure used in several DBS management dialog panels.

The Action Bar

When using the DBS dialog box, do not overlook the Action Bar:

The Edit menu allows you to change such things as the Work Group settings and information.
The GoTo menu is a useful way to go directly to the panel in which you are interested.
Help is self-explanatory.

All items are available in every panel.

Important information regarding the UNSYNC Indicator: When the Configuration you are editing does not match the JESplex on which you are running, the status is shown in the upper right of the screen as UNSYNC.

DBS Objectives

DBS has been designed to provide a completely automated solution to the problem of allocating a serially reusable resource: tape drives.

The only demand that DBS makes on your installation before it can function is that you must define the tape subsystem environment to DBS.

This definition is a simple process that is assisted by a comprehensive ISPF dialog. If your environment is simple, then the definition process is extremely simple. If your environment is complex (many different devices and lots of asymmetries) then the process is a bit more elaborate. The point here is that the complexity of the definition process is related to the complexity of your environment. Fortunately, the ISPF dialog acts as a “complexity reducer”, dampening the magnification effect that complexity creates.

Although the algorithms and processes used to manage your installation’s tape drives are complex, DBS is straightforward to set up, and once implemented requires little intervention.

Overview of DBS

The first function of DBS is to manage the totality of drives available to the JESplex.

The second function, which is optional, allows the logical separation of drives to provide resources to different work groups. Of course, subdividing must take place within the boundaries of the available drives.

To manage the drives, DBS uses these resources:

Drive Pools manage the physical devices (device numbers).
Work Groups manage the logical segmentation of workload.

Externally, DBS requires a user-defined Configuration and Policies to determine how your installation wants to manage tape drives. These are defined with ISPF dialogs. DBS also uses ISPF to provide monitoring and display facilities.

The Configuration, Policies, Drive Pools, Work Groups, and how they fit together are described in more detail in the next topics.