Chapter 6 NI-VXI Configuration Utility
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National Instruments Corporation 6-7 VXI/VME-PCI802 2 for Sola ris
VXI/VME Shared Memory
The VXI Shared Memory group contains the controls to set the VXI
and VME shared RAM size and the shared RAM pool. The Advanced
button leads to additional options that configure the upper and lower
half of the shared RAM area.

VXI/VME Shared RAM Size

This field indicates the amount of RAM (in bytes) that is shared in
either A24 or A32 space. This determines the total shared RAM size,
which is then divided into two equal halves that you can set up
independently of one another.
Note: When the Address Space field is in the default setting of A16 only, this
field is ignored.

Shared RAM Pool

This field indicates the size of memory (in kilobytes) that is allocated at
startup. This memory is used by the lower/upper half window when the
Memory Select control (accessible through the Advanced popup field)
is set to System memory.
The following table indicates how the Shared RAM Pool relates to the
VXI Shared RAM Size depending on the setting of the Memory Select
control for the upper and lower half windows.
Memory Range Default Value
0 to 65535 KB 0 KB
Lower Half
Window Upper Half
Window Shared RAM Pool
(Window)
System memory System memory Equal to VXI/VME
Shared RAM Size
System memory Onboard memory Half the VXI/VME
Shared RAM Size
Onboard memory System memory Half the VXI/VME
Shared RAM Size
Onboard memory Onboard memory 0