Moving the Temporary Internet Files storage cache onto a Storage Card

Applies To

• HPC2000
• Windows CE .net 4.0, 4.1, 4.2

Overview

By default, when you browse the Internet on your Handheld PC, the web pages which you view are downloaded into Storage Memory to improve page load time performance as you navigate back and forward through internet pages. The cache, identified to the system as the Temporary Internet Files cache, also serves as a bandwidth reduction mechanism, preventing pages from being downloaded unnecessarily.

This article discusses how to move the cache shell folder from its default position under the Windows folder, onto an external storage device. In addition, the relocation of the shell folders Cookies and History is covered as part of the document.

How-to Guide

By default, the Temporary Internet Files cache folder is held within the object store under the folder hierarchy \Windows\Profiles\guest\Temporary Internet Files\. The cache makes use of a series of alphanumeric sub folders to span content from different sites, and with different names within the same cache archive. Content stored within the Temporary Internet Files hierarchy is indexed by the index.dat file located on the root of the cache.

The Temporary Internet Files path information is stored beneath the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\Cache\Paths, this path is assembled by the system ad-hoc, and cannot be manipulated by the user in a functional way. This section of the registry is dynamically built based upon the individual user preference settings of the active Windows CE user account - in this case the guest account - from path information stored under HKEY_CURRENT_USER.

Before attempting to alter the location of the shell folders from main memory, the user must consider the implications of removing the Storage medium from the system before or during an Internet Explorer session. Under such circumstances, Windows CE will automatically return the location of the cache to a user profile neutral location at \Windows\Temporary Internet Files.

At the next soft reset the store will be returned to the specified folder, however the cache and all of its contents will remain resident in storage memory, and will not be purged by the Clear Cache feature of the Windows CE browser.

To change the path of the Temporary Internet Files, Cookies or History shell folders.

1. Close all Pocket Internet Explorer / Internet Explorer CE sessions
2. Create the folder hierarchy on your external storage medium where you will place the new shell folders folder, for example:
   \Storage Card\System\Temporary Internet Files\
   \Storage Card\System\Cookies\
   \Storage Card\System\History\
3. Open your Handheld PC's registry editor
4. Navigate to:
   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\
5. Edit the Cache, Cookies and History string values to match the path to the new location. The full system path must be used and should not be suffixed by a trailing \. The location must be within the bounds of the Windows CE file system environment and must not be entered as a network share or onto a device to which you lack write permission
6. Exit your registry editor and soft reset your Handheld PC

Your Internet shell folders will migrate to the storage medium when you next launch the web browser.

Notes

• Windows CE will revert to a fail safe store if the storage card is not present, however the data will become stuck in RAM once the storage card is detected and will need to be cleared by hand.
• Repeated use of the device on-line with and then without the storage card present will cause a synchronisation issue between the two caches. Users making use of Internet access technologies being charged by the byte/ KiloByte/MegaByte should be aware of the cost implication of re-sycnhronising multiple cache stores
• The old shell folder stores will not be purged from the system as part of this process. It is recommended the user delete the folder hierarchy to free up space in the object store.
• High volume Internet users should be aware that processing cache information on some solid state flash technologies could severely reduce the functional life of the card due to accelerated write/rewrite degradation.