An Administrator of System Architect XT must set the Desktop Heap memory allocation of the server computer that deploys System Architect XT to a value that properly supports the anticipated number of concurrent users. Each System Architect XT session requires 37KB of Desktop heap. In Windows the amount of Desktop heap available is controlled by a registry setting.

In Windows the amount of Desktop heap available can be modified in the following registry subkey:

The default value for this subkey usually looks like this:

The SharedSectionentry in this subkey controls the number of KBytes allocated to each of three different types of Desktop Heaps. System Architect XT uses the third value(512) in the SharedSection. In this example the system will allocate 512Kb of space for all the System Architect XT sessions to share, which will allow 12 sessions of System Architect XT to be run concurrently.

Modifying this value can impact other applications running on the same computer so if the value in this subkey needs to be modified the following document on the Microsoft website should be reviewed first:

The System Architect XT web.config file contains an appSettingsentry that must be set to match the value in the registry. The key MaxDesktopHeapshould have its value set to the same value specified in the registry. This web.config entry allows System Architect XT to ensure that users do not attempt to start sessions that would cause this allocation to be exceeded.

In the example below, the MaxDesktopHeap is set to 512.