HP Compaq t5125 Introduction Manual page 5

HP System Update searches the following types of files (listed in the order in which they are searched):
1. HP image files (*.IMG)
2. Add-on files (*.CAB)
3. Thin client setting files (*.ARP)
NOTE: Each thin client comes with a license and can also be managed by the Altiris Deployment Solution. Altiris
images created using RDeploy or RDeployT also end with the file extension .IMG. Altiris images are not
compatible with the HP System Update.
HP System Update minimizes network traffic by pulling only new files. To determine which files are newer,
System Update stores and compares the following types of information:
•
HP image files—internal image identification
•
Add-on files—Filename and date/time stamp of file
•
Thin client setting files—Filename and date/time stamp of file
1. Every Microsoft CE image file from HP contains an internal image-identification. System Update
compares the FTP hosted internal image-identification with the internal image-identification of the CE
OS that is running System Update. System Update does not download the entire image file to query
the identification of the image file. Instead, it downloads only enough to obtain the identification. If
the identifications are different, then System Update pulls the image file from the FTP server and
installs the image file on the thin client. On the next forced reboot, the thin client runs the new image
along with its new identification, which now matches the identification of the image file on the FTP
server. System Update will no longer pull this file until the FTP server contains a different image file.
2. Unlike the HP image files, add-on files (*.CAB) do not have an internal stamp for comparison. System
Update instead uses the FTP server's file system date/time information of the add-on file. System
Update also compares the name of the file. As a result, System Update will not pull the add-on file if
both the filename and the date/time stamp match any of the previously installed add-ons.
3. Thin client setting files (*.ARP) are compared as described above (2).
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