1.2.1 IBM i Slave Systems

An IBM i Slave is a Visual LANSA System on a Windows PC connected to a Master LANSA System running on an IBM i.

Master LANSA System

A Master LANSA System is identified by its ability to maintain its LANSA System Definition Data. Master LANSA Systems are independent. The Master System Definition Data is loaded when a system is installed or upgraded. LANSA Repository data can be imported from another LANSA System. (A Master LANSA System does not use a host monitor.)

If you use LANSA for i on an IBM i it is always a Master System. Each LANSA for i System may have a Slave Visual LANSA System.

A Visual LANSA System on Windows can be a Master System but it does not have any Slave Systems. It can have Clients, which can use the Repository data for development. Refer to 1.2.4 Independent Windows Server for more details.

Slave LANSA System

A Slave LANSA System is not able to maintain the LANSA System Definition Data. It receives its system definition from a Master LANSA System. It is dependent upon the Master LANSA System. The System Definitions must be updated on the Slave system whenever a change is made to the Master System.

A Slave LANSA System is loosely coupled to a Master System. It works separately from the Master System, but needs to obtain permission from the Master to make modifications to LANSA objects. It also obtains the latest version of an object from the Master System. And when the changes have been made they are checked back into the Master System. Only one Windows PC at a time has authority to make changes. Once a Windows PC has obtained authority, no other Windows PC will be permitted to change it.

A Slave LANSA System exchanges Repository data with the Master System using a host monitor to check-in and check-out Repository data from the Master LANSA System.  For more details about the host monitor, refer to Host Monitor in the Administrator's Guide.)

A Visual LANSA System can be a slave to only a LANSA for i Master System. It cannot be a slave to another Visual LANSA System.

You may have multiple Slave Visual LANSA systems on different Windows PCs accessing the Master LANSA Repository on a single IBM i.

Developing with Master and Slave Systems

When developing LANSA applications with Master and Slave Systems, there can be only one Master LANSA Repository. The Master LANSA Repository typically resides on the IBM i with the Master LANSA for i System.

The Visual LANSA Slave system also has a local or Slave LANSA Repository. The Slave Visual LANSA Repository contains copies of the objects from the Master Repository that are in the process of being developed or maintained using Visual LANSA. Visual LANSA uses a database management system on the workstation to store the local LANSA Repository.

Two types of information are stored in the LANSA Repositories:

It is very important to keep the LANSA system definitions and LANSA application definitions synchronized. LANSA provides a number of facilities to assist in this task. Refer to 1.2.10 Synchronizing Master and Slave Systems.

One of the IBM i Slaves will need to be designated as the Build Machine. See 1.2.8 Windows Build Machine