Issue
NRE default configuration and RAM disk removal
Product Line
TAC IA Series
Environment
I/A Series N4.11 Jace 8000
Cause
In Niagara 4.10u1 and earlier, the RAM disk was used to temporarily store alarm and history data. During station save, this data was copied from the RAM disk and zipped up, and stored on Flash. In Niagara 4.11, the RAM disk has been removed entirely. This data is now written directly to the Flash.
Resolution
A change to the JACE-8000 file system has been introduced with the release of Niagara 4.11. The RAM disk was used to store alarm and history data. During station save, this data was copied from the RAM disk and zipped up into a single file that was stored on flash. In Niagara 4.11, the RAM disk has been removed entirely. This data is now written directly to the flash memory.
This change has enabled ~384MB of RAM to be freed up to improve performance. Some of the space has been reallocated to code cache, metaspace, and heap space in the 4.11 NRE default settings. Any additional memory space is now available as general free memory.
JACE-8000 NRE Memory Default for (older) Niagara 4.10 - sizes in MB:
System Reserve Size: 0
Heap Space Size: 360
Meta Space Size: 56
Code Cache Size: 16
RAM Disk Size: 384
Free Memory: ~16
JACE-8000 NRE Memory Default for (newer) Niagara 4.11 - sizes in MB:
System Reserve Size: 0
Heap Space Size: 384
Meta Space Size: 64
Code Cache Size: 32
RAM Disk Size: Not present (cannot be created)
Free Memory: ~352
These changes should be transparent to most users and will provide moderate performance improvements on the JACE-8000.
