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CF & Windows XP Embedded + EWF/HORM
I've done my research on a lot of car pc related forums and know XP embedded pretty well and have been tinkering with CF whilst running HORM.
Here's the problem:
When running XPe with EWF the system volume is protected and the hiberfil.sys hibernation file bypasses EWF and is written to the protected volume. The system can then resume from the hibernated state rapidly so that Windows can resume from where it left off. Any changes made that need to be committed to the protected volume are lost whenever it is shutdown (RAM overlay). Thus allowing a fast load up time and no major headaches when it comes down to power issues.
One issue with this is that if you have a second volume mounted (or partition etc) which is unprotected by EWF and it is mounted whenever the initial hibernation is performed then the write cache for this mounted unprotected volume is committed to the protected system volume within the hiberfil.sys. This effectively means that anything written to the unprotected volume is lost and is a recipe for disaster as the system effectively thinks the file system is then corrupt.
What I want to achieve is the following:
An XPe machine that uses EWF & HORM which has CF running during the initial hibernation so it is running automatically on resume AND allows for the user to change settings within CF which are persisted - things like last song playing, updatable music library etc. All without having to re-commit changes to the EWF protected volume.
To achieve this the following has to be done:
One machine with two disks (doesn’t matter what format, regular HDD, SSD,USB, Compact Flash).
First disk is the system one which will include the OS files and the registry which will be fully protected by EWF. Hiberfil.sys is obviously stored here too.
The second disk is the data disk which will host the Centrafuse application itself (maps, settings etc)
I know that CF creates a user profile directory for its music DB (main.dat) etc. under {local settings\application data\centrafuse}. By creating a junction prior to installation & initial hibernation, to the second disk for this folder then it means that all of the files necessary for CF to run correctly will be stored on the data disk.
The issue then becomes if CF is running it always has a file handle on the data disk no matter what is going on. As the unprotected data volume has to be dismounted prior to the initial hibernation in order to prevent corruption then something has to be implemented within CF to release all file handles within the running process prior to hibernation which will then allow for a script to be executed (from the system drive) to dismount the data volume cleanly. Then when the system boots back up from the hibernated state XP will automatically remount the volume cleanly and CF should be able to re-create the handles for its files in order for it to run.
Does this sound feasible or has someone already been able to do this with CF?
I've looked at using SDI disks but again it all relies on having the running application not to have any active handles on the unprotected volume.
I've also looked into suspended the CF process and forcebly closing the handles but it doesnt like it upon resuming the process.
Thanks & Regards,
Wez
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