Echelon i.LON 100 e2 Internet Server - Manual (Page 70)

5-4 Managing the i.LON 100
i.LON 100 Model Information
This section of the System Info Web page displays i.LON 100 model
information. This information may be requested by Echelon support when
diagnosing a problem with the i.LON 100. This part of the web page shows the
following information:
Model Number
The model number of the i.LON 100.
Channel Type The channel type of the i.LON 100. Either TP/FT-
10 or PL-22.
Modem Installed Indicates whether the i.LON 100 has an internal
modem.
CPU Speed The CPU speed of the i.LON 100, in MHz.
Firmware Version The firmware version of the i.LON 100.
Bootrom Version The bootrom version of the i.LON 100
i.LON 100 Flash Information
This section of the Web page shows information on flash memory usage. The
i.LON 100 uses flash memory to store data associated with its applications, such
as the log files generated by the Data Loggers and Alarm Notifiers that you have
created. This non-volatile memory appears to the i.LON 100 applications as a
logical 32 MB disk drive (also called a "flash disk"). The flash disk is extremely
reliable and should last a long time, but it has some limitations that may affect
the lifetime and runtime configuration of the i.LON 100.
The flash memory is physically composed of 2048 blocks of 16 KB each (these are
not the same as disk blocks/sectors, which are much smaller). 2000 of these
blocks are mapped to the logical disk drive, 2 are required for overhead, and the
remaining ones (up to 46) are spares.
Once a flash block has been written to, it must be completely erased before it can
be written to again. As the i.LON 100 applications write data to the logical flash
disk, physical flash blocks are erased as needed to allow data to be stored. Each
flash block can be erased a limited number of times before it fails, and flash
manufacturers specify a minimum expected value for this limit. When a flash
block fails, it is permanently marked as failed and no longer used by the i.LON
100. The spare flash blocks allow for a limited number of block failures to occur
without affecting the reliability of the flash disk.
The amount of time it takes for the flash blocks on the i.LON 100 to reach their
erase limit depends on how much and how often data is written to the flash disk.
Writes to the logical flash disk cause erases of physical flash blocks, but there is
no simple formula to precisely describe this relationship. The flash erase rates
reported by the i.LON 100 apply to the entire flash memory, not to individual
flash blocks. The i.LON 100 contains a sophisticated flash file system that
distributes flash erases across all available blocks, in order to optimize the flash
life. Over time, the actual number of erases of each block will remain
approximately equal, thus maximizing the lifespan of all flash blocks. According
to the flash manufacturers' rated limits, all flash blocks should last at least 10
years if the total block erase rate averages no more than 39 erases per minute for
that entire time. Exceeding this limit may cause the flash disk to wear out
sooner.