HP T5125 - Compaq Thin Client Reference manual

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Advantages and Implementation of DHCP-enabled HP
Automatic System Update for Microsoft Windows CE 5.0 on
HP Compaq t5000 Series Thin Clients
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
HP Automatic System Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
How It Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
An Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Where to Obtain the HP Image File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
For more information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

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Abstract
With the introduction of Microsoft Windows CE 5.0 for HP Compaq t5000 series thin clients, HP
Automatic System Update enables a lightweight network mechanism to update image binaries and
settings. System Update is a pull technology initiated by powering on the HP thin clients. By solely
leveraging DHCP and FTP standards, System Update requires nothing to install and minutes to learn.
Introduction
HP Automatic System Update allows HP Compaq t5000 series thin clients running Microsoft Windows CE
5.0 to synchronize images and settings from centralized DHCP and FTP servers.
Because of the small footprint of the CE 5.0 image developed by HP, customers can quickly and efficiently
distribute full images. Unlike a traditional PC, the typical size of a CE 5.0 image for HP thin clients is
relatively small at 32MB.
HP Automatic System Update fits into a variety of situations including, but not limited to, the following:
•Removes the need to ship thin clients to staging facilities for initial unit setup of software and
configuration; customers can update devices as they're connected to the network for the first time
•Quickly propagate image updates as part of IP address lease process
•Distribute software updates quickly and easily without rebuilding thin client images or deploying
other management tools
•Propagate thin client settings without transferring whole images—ideal for low bandwidth situations
•Enables rapid replacement of terminals to minimize lost data and impact to productivity
HP Automatic System Update
Limitations
System Update is not a complete remote management solution.
Altiris Deployment Solution's standards-based, advanced thin client management solution (which is
included with every HP Compaq t5000 series thin client) is the comprehensive mechanism for updating
and maintaining HP Compaq t5000 series thin clients. Any image deployment plan should evaluate
Altiris Deployment Solution before HP Automatic System Update.
System Update does not support grouping, reporting, event notifications, remote control, wake-on-LAN,
and many other features that Deployment Solution offers.
In addition, System Update works only on HP Compaq t5000 series thin clients running Microsoft
Windows CE 5.0, and should not be used with images based on CE 4.2.

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How It Works
HP Automatic System Update is broken down into four stages:
1. TC →DHCP Discover a DHCP server
2. TC ←DHCP DHCP Server responds with FTP location
3. TC →FTP Thin client searches FTP server for file(s)
4. TC ←FTP FTP server sends file(s)
NOTE: If the network environment uses static IP addresses, the thin client can bypass Stages 1 and 2. Figure 3
shows how one would configure System Update without the use of DHCP.
Because HP has preconfigured its release of CE 5.0 to be DHCP-enabled for system updates, customers
can immediately and automatically deploy image and/or software updates and/or system configurations
with minimal effort using an FTP server.
The thin client determines the file server and file path locations by referencing two DHCP Options
numbers. By default, these DHCP Option numbers are 161 (FTP Server Address) and 162 (FTP File Path).
The thin client displays this information in the DHCP Options applet under the control panel (see
Figure 1).
Figure 1 Verifying that FTP information from the DHCP server is correct

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Figure 2 System Update configured with DHCP
Figure 3 System Update configured without DHCP

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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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An Example
Assume the FTP Server with a host name of Bingo contains the following files:
•C:\Inetpub\ftproot\tc_deployment_files\build527.IMG
•C:\Inetpub\ftproot\tc_deployment_files\NewICA.CAB
•C:\Inetpub\ftproot\tc_deployment_files\build527_NewICA.ARP
Further assume a brand new, factory-delivered thin client with a different version of the image than
build527.IMG.
The following events occur when turning on this brand new thin client:
1. TC ←DHCP Server DHCP Server responds with DHCP Option #161 with the data of “Bingo” and
Option #162 with the data of “\tc_deployment_files”.
2. TC →Bingo TC searches for “\tc_deployment_files\*.IMG” and finds “build527.IMG”.
3. TC ←Bingo Bingo sends a small piece of the build527.IMG file that contains the internal
image identification. The TC compares the value with its running version, sees
the difference, and downloads and installs build527.IMG.
4. TC reboots TC forces an immediate reboot.
5. TC →Bingo TC searches for “\tc_deployment_files\*.CAB” and finds, downloads, and
installs “NewICA.CAB”.
6. TC →Bingo TC searches for “\tc_deployment_files\*.ARP” and finds, downloads, and
imports “build527_NewICA.ARP”.
7. TC reboots TC forces an immediate reboot.
8. TC boots to desktop TC is deployed and ready.
CAUTION: The thin client settings file (*.ARP) must have been exported from another thin client that was already
running Build527.IMG + NewICA.CAB. Otherwise, System Update rejects the ARP file in event 6 above.
Where to Obtain the HP Image File
To download the latest HP Image files (.IMG) for the specific t5000 series model, visit HP's thin client
Web site (www.hp.com/support). Select Download drivers and software, enter the specific thin
client model, press Enter, and select the operating system.
Execute the downloaded file on a PC and select the Deployment option to extract the HP Image file
and copy it to the PC's hard drive. Then copy the files to the deployment file share on the FTP server.
Conclusions
HP's DHCP-enabled System Update delivers customers a powerful, yet simple and low-cost, deployment
method. By leveraging the scalability and scope control of DHCP, HP System Update requires very little
additional training and capital investment.
By not creating any proprietary network protocols, HP System Update adapts to existing site
infrastructures.

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For more information
www.hp.com/products/thinclient
www.altiris.com/products/deploymentsol
www.altiris.com/eval/hpthinclient
© 2005 Hewlett-Packard Development Company, L.P. The information contained herein is
subject to change without notice. The only warranties for HP products and services are set
forth in the express warranty statements accompanying such products and services.
Nothing herein should be construed as constituting an additional warranty. HP shall not be
liable for technical or editorial errors or omissions contained herein.
Microsoft and Windows are trademarks of Microsoft Corporation in the U.S. and other
countries.
403670-001, 7/2005