Wegener Communications 6420 User Manual

Page of 135
 
 
iPump 6420 User’s Manual 
 
 
www.wegener.com 
800070-01 Rev B 
Chapter 3, Page 88 
3.5.3. 
File Return for Audit 
As the captured OAR files accumulate on field i6420s, the Compel system may regularly 
request that they be returned so that they are available for auditing.  This is done through the 
Return Path OAR file return report.  This will cause the field iPump6420 to upload all OAR 
files, by HTTP POST, to the CSM function in the Compel system.  The CSM function, in turn, 
will place the files to a directory for that unit serial number.  After the request has been accepted 
and executed, the iPump6420 will move the OAR files that were sent to a hidden folder 
/u/user/.system/oar/.to_be_deleted.  All files therein are watched by another internal 
maintenance process.  When their age exceeds the automatic deletion time, then they are quietly 
deleted. 
The relevant user controls are
1.  OAR Return Path request 
2.  OAR file auto-deletion time, in days 
3.  OAR file auto-deletion time of day 
3.6. Miscellaneous 
Functions 
3.6.1. 
Application Management 
The Linux OS and the linux application that implements the Local Controller, per Figure 1-
3, both have their code stored in a flash memory card.  The code is stored there, rather than the 
hard-drive (HDD), so that the unit will function, albeit as a more limited “IRD”, in the event that 
the unit’s HDD fails.  Storage of the application software is done in two redundant locations.  
This allows the network operator some measure of security when trying to control many remote, 
field iPump6420s, especially when local users are unable to, unwilling to, or restricted from 
assisting in the proper management of the unit. 
Redundant Application Images 
Normally, the unit holds two versions of the application code and one is specified to be the 
commanded” application.  At unit reboot, a boot loader function evaluates the non-volatile 
instructions specifying which application to load, and the stored flags indicating the status of 
those application images.  If an application image is known to be “good”, and it is the currently 
commanded (or “primary) version, then it is loaded and run without further qualification.  If 
the currently commanded (primary) application image is not known to be good, for any of 
several reasons, then the boot loader will load the alternate (“backup”) version, if it is known to 
be good.  Also, if the boot loader attempts to load and run the commanded application, and if, for 
any reason, the application cannot be run, then the boot loader, after a few attempts, can revert to 
the backup application, loading and running that.  It will also mark the failing application image 
as “bad”, avoiding later re-attempts to load and run it.  The exceptions to these scenarios can be 
discussed shortly, after describing the application upgrade process. 
Software Upgrade process 
To upgrade software in unit, Compel, or the local web user, may download a new 
application image to the running system.  This is in a special format which uses a *.dl extension, 
and it is downloaded to the /u/user/.system/dlfiles directory, which is a “hot folder”.*  There,