Bob Understand

What Understand does

A long-running IBM i application can hold thousands of objects. An object is any named thing on the system, such as a program, a file or a service program. Those objects lean on each other. One program calls another, opens a file, or fires a database trigger. A dependency is simply one object needing another. Understand writes all of that down in one place. IBM describes it as giving Bob an accurate map of how every object in an IBM i application connects.

Picture a city with no street map. To find out where a road goes, you have to drive it. That is what Bob was doing before: reading the source code again every time you asked a question. Understand hands Bob the map instead.

With the map in hand, Bob answers structural questions from the scan data. IBM names three uses on its own overview: impact analysis, application overviews and program-level explanations. Impact analysis means asking what else is affected before you change one program.

How does the scan work?

IBM states the payoff plainly. Bob queries that schema instead of re-reading source on every prompt, which means faster answers, fewer Bobcoins spent, and responses grounded in facts rather than model inference. Bobcoins are the units IBM meters Bob usage in, so a question that reads the map instead of the source is a real saving.

What does the scan record?

• Object types, and the language each object was written in.
• Program calls, in both directions. Understand traces callers and callees, so you can see who calls an object and what that object calls.
• File opens, which show you the programs that touch a given set of data.
• Static bindings, the fixed links between a program and a service program.
• Triggers and foreign keys, the rules the database enforces on its own.
• SQL views built over the files. SQL is the standard language for asking a database questions.
• Exports and file references held by each object.

The scan also flags how hard a program would be to modernize. IBM says programs are sorted into Low, Medium and High effort using OPM against ILE status, how many dependencies they carry, whether they use dynamic SQL, and when they were last used. OPM is the older Original Program Model. ILE is the newer Integrated Language Environment that replaced it.

What can Bob ask the map?

What do you need before it works?

• An active connection to an IBM i system through Code for IBM i, the free Visual Studio Code extension.
• SSH running on the IBM i system. SSH, or Secure Shell, is the service that lets another machine connect in safely.
• The Bob Premium Package for i, which IBM sells as an add-on to a paid Bob base plan.