Chapter 6 NI-VXI Configuration Utility
© National Instruments Corporation 6-7 PCI-MXI-2 for Linux
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.
The shared RAM pool is used by VXImemAlloc() function calls. For
information on the VXImemAlloc() function, refer to the NI-VXI User
Manual and the NI-VXI Programmer Reference Manual.
Memory Range Default Value
0 to 65,535 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