58 Chapter 2 Distributing Applications
InTouch HMI Application Management and Extension Guide
Changes to an Application During a NAD Update
When the WindowViewer node updates an application, it
makes every attempt to retain the attributes (read-only,
system, hidden, and so on) of the master application during
the copy process.
WindowViewer also copies all files and subfolders of the
master application, except for these files: *.WVW, *.DAT,
*.LGH, *.IDX, *.LOG, *.LOK, *.FSM, *.STG, *.DBK, *.CBK,
*.HBK, *.KBK, *.LBK, *.NBK, *.OBK, *.TBK, *.WBK,
*.XBK, *.$$$, RETENTIV.X, RETENTIV.D, RETENTIV.A,
RETENTIV.S, RETENTIV.H, RETENTIV.T, SSD_, WM.INI,
DB.INI, LINKDEFS.INI, TBOX.INI, GROUP.DEF, and
ITOCX.CFG.
Note WindowViewer recursively deletes all files and subfolders in
the destination application folder except those required for
run-time language switching. This folder should be considered a
temporary folder. No other files should be placed in it.
The NAD client starts an update by creating a local list of
files and sub-directories that appear in the client application
directory. As it looks for updates in the list of master files,
the NAD client removes the corresponding client file for each
master file from the local list. The remaining entries in the
local list are obsolete files and sub-directories that should be
deleted from the application.
All downloaded files are copied to a temporary sub-directory
called NAD_Temp. Files are only copied from NAD_Temp to
the application directory if all of the new and updated files
are copied successfully within the re-try limits. If the NAD
client has to abandon an update, the running application is
not corrupted by the partial introduction of new or updated
files.
If contact with the NAD master fails after all new and
updated files have been downloaded, the update can still be
completed by copying the updates from NAD_Temp and
deleting the obsolete files. This ensures that files are not
erased simply because a lost connection makes it impossible
to confirm their existence on the master application.
NAD can detect whether additional changes have been made
to the master application during application download. If
such a situation arises, NAD abandons the download of the
application. If you run the
Notify Clients command after the
latest update, NAD automatically begins downloading the
latest application files at the next polling period. Otherwise,
it waits until the next
Notify Clients command issued before
an application download takes place.