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By Destination Z posted Mon December 23, 2019 03:43 PM


So you’re interested in SPOC. Maybe you spent hours watching the original Star Trek series or have an affinity for pointy ears. Or perhaps more likely, maybe you’re an IMS systems programmer or database administrator who manages lots of resources across multiple IMS systems, and it’s gotten so complicated to the point that you’re now in orbit.

Either way, you might be wondering what SPOC has to do with IMS, or how he can help you simplify the way you manage your IMS resources. Well for starters, “he” is really an “it.” In the world of IMS, SPOC stands for Single Point of Control, and it’s a function of the IMS Common Service Layer (CSL) that simplifies IMSplex management. “Great!” you say. “But we’ve got a set change-management process, and if it ain’t broke, don’t fix it.” But wait, not so fast.

Prior to the CSL, the primary method of issuing IMS commands was via a terminal or system console. Managing more than one IMS system required toggling between different consoles to keep track of them separately. If a command failed on some systems but succeeded on others, you’d have to keep track of this desynchronized state and manually intervene to sync the systems backup. Fun times, no?

Single Point of Control
SPOC alleviates these issues, in particular, a certain type of SPOC called the time-sharing option or TSO SPOC application, which comes with the base IMS product. There are two other types of SPOCs as well, which we’ll cover in a bit. The TSO SPOC provides a single-screen interface from which you can see your entire IMSplex, route commands to any or all systems in it, and view the consolidated command response associated with each system. No more flipping between different consoles to determine the status of different systems and their associated resources. Unsolicited messages can also be viewed within the TSO SPOC, and you can control which messages are sent: those destined for the master terminal operator (MTO), the console, or both. The TSO SPOC also allows you to easily repeat previously issued commands, permits command nicknames and shortcuts so you don’t have to remember command format, and lets you group IMS systems together so you can easily target a group with a single command.

Next, there’s another type of SPOC that’s best used in batch processes: the Batch SPOC utility, which also comes with the base IMS product. With this utility, you can submit “online” commands to your IMSplex using Job Control Language (JCL) statements. You can even choose to skip commands in a batch job step based on the resulting condition code of a prior step.

To take this a step further, you can use the final type of SPOC to create intelligent automation with the REXX SPOC API. Using this API, you can write a REXX program that can actually examine command responses to autonomically determine what action to take next. A nice side benefit is that new IMS hires fresh out of college who are familiar with REXX could take this opportunity to leverage their skill in a world before their time!

So, we’ve established that SPOC provides the same functionality as the traditional method of issuing commands from a terminal or a console. But why else should you be using it?

Type-2 Commands
Clearly, SPOC makes maintaining your IMSplex a much easier job. You might be wondering, “But why use type-2 commands if SPOC supports type-1?” The reasons are numerous.

Not only do type-2 commands have a greater breadth of functionality, but also because the future direction of IMS is aligned with type-2 commands, each new release will likely contain several new capabilities that require command usage in this format. You will rarely see type-1 commands being enhanced, and it’s even less likely that new commands will be developed in this traditional format. Therefore, to take advantage of new IMS functions, you must be able to issue commands in this newer format. Type-2 commands are also more powerful than type-1 and offer benefits like increased flexibility with wildcard capability, additional information included in the output response, audit trail capability, and filtering capability so that you only see information in the response that you’re interested in. Some commands even provide coordination among multiple IMS systems, using the Resource Manager CSL component. Just one example of this is global online change, in which all IMS systems will always point to the same active/inactive online change libraries, even if a command fails on one of the systems. This is especially valuable in a cloned IMS environment, in which maintaining synchronization is crucial.

Type-2 commands also enable a greater level of granularity for secure access. For example, you can restrict access to a command that would update resources with a specific name, whereas with type-1 commands this isn’t possible. In other words, type-2 commands allow security restrictions based on both primary and secondary keywords, whereas type-1 commands do not.

Since SPOC supports both type-1 and type-2 command formats, you can initially continue to use the type-1 commands you’re familiar with to administer your IMS system(s). Then, as you become more comfortable with type-2 commands (and enthused with their many benefits), you can slowly transition to using this new format. And not to worry, there’s an equivalent type-2 command for almost every type-1 command you’ve grown to know and love over the years.

Final Frontier
As you can see, using the IMS SPOC capability opens up lots of doors, and since it’s part of the base IMS product, it’s free. Whether you’re a trekkie or not, SPOC usage is part of the next generation of IMSplex management. Use it to get the most out of your IMS investment and start managing resources across multiple IMS systems in an easier, simpler way! After all, it’s in the stars.

Angelique Greenhaw is a senior IT specialist with IBM System z Software’s IMS Advanced Technical Skills group.