Hibernation Mode for EL-Torito CD images?

[Santiago Allen]

Hi all,

I have been reading in the msdn on how to reduce boot time of an image
and one of the more interesting topics deals with having the system
boot from a hibernated point: (Link)
http://msdn.microsoft.com/library/d...owtoconfigureewftobootfromhibernationfile.asp

Is this possible if one intends to use an El-Torito CD Image? I would
guess that once the fba is set up, one could follow these steps before
ETpreping the drive. But is this available? Has anyone tried this?
My concern is that the hibernation file will be as Big as the size of
Ram in the system right? If Ram is 256 MB and the total footprint of
the system is another 140-160 uncompressed, Over 400MB of the 700MB are
used. That doesnt leave much for apps. Any suggestions?

Santiago Allen

 

[Slobodan Brcin \(eMVP\)]

Santiago,

Resume can't be executed from CD, not by default anyhow.

Regards,
Slobodam

 

[Santiago Allen]

Santiago,

Resume can't be executed from CD, not by default anyhow.

Regards,
Slobodam

Hi Slobodan,

What do you mean by "not by default"? Is there no way to do this?

Thanks

 

[Slobodan Brcin \(eMVP\)]

Santiago,

What do you mean by "not by default"? Is there no way to do this?

I said that there is no default MS way to do that. Not that it is
impossible.

1. You could create el-torito driver with CD burn capabilities.
2. When you hibernate it might be possible with additional driver to erase
recordable CD and write new content that will contain HORM file.

So with additional research on this approach and too much work this could be
written. But I do not think that anyone is so desperate for such option.

Regards,
Slobodan

 

[Santiago Allen]

Thanks Again Slobodan,

Not to beat a dead horse though, but this doesnt make sense to me.

The point is to enable a Hibernate-once Resume-many environment. The
EWF is enabled so that the primary (and only) volume may not be written
to. This means that the hibernation file hiberfil.sys should not
change once it is created. The El torito CD allows a CD to act like a
hard disk. Since EWF is enabled the CD cant be written to anyways. So
why do I need to have the ability to write to the CD? There must be
something about the way hibernation works that I dont understand, is
there anything online I can read to understand why this wouldnt work?

Thanks Again

Santiago Allen

 

[Slobodan Brcin \(eMVP\)]

Santiago,

One simple thing that you should answer to us and then we will solve this:
How do you plan to move hibernation image and all files to CD without
changing FS content on HDD and CD? This is an idea of hibernation.

While OS is hibernated files must not change in other to keep consistency
with caches in memory that are written to hiberfile.

Regards,
Slobodan

 

[Santiago Allen]

Hi Slobodan,

I think I understand what you are trying to say. Let me see if I can
recap.

"etprep" needs to be done to finalize the image for transfer to cd
right? If I set the hibernation file before I "etprep", my hibernation
file will be wrong because it wont put me back in a position where the
system understands that the hard drive is gone and now the CD-Rom is
acting as a hard drive. So then the trick would be to "etprep" before
the hibernation image is set. Using the actual utility may not be
possible because it reboots...but doing what etprep would do and not
rebooting may work no?

This leaves the File System change. What if, after hiberfil.sys is
created, I edit this to look proper for the CDFS? Then my HD would be
ready for the HD2Iso tool and the resulting CD would behave properly,
no?

Thanks again,

Santiago Allen
(Still a Newb)

 

[KM]

Santiago,

I don't know how well you understood the Slobodan's post but I read your message as not correct understanding.
The etprep itself does not cause the problem. But CD-ROM FS (CDFS) is different from a HDD FS (NTFS, FAT).
When you hibernate, the hiberfil.sys file will have a snapshot of your RAM at that point including the system's file system cache in
RAM or whatever is there. When you resume (that is where the actual problem happens) and the file system on the boot (or any)
partition is NOT in sync with what was captured in RAM - you are going to destroy the working system and it may sometimes damage the
file systems on your media (not on read-only CD, of course ).

Anyway.. nothing prevents you from trying out what you were about to try but be ready to possible waste a blank cd.

 

[Slobodan Brcin \(eMVP\)]

Santiago,

When doing HORM you must trick XPe in not seeing any differences between the
time when you hibernate and when you resume.
This level of virtualization can be done only by very low-level drivers.

Registry is too high thing and it is irrelevant. Like I said you must trick
OS in not seeing difference between original HDD and CD. This is probably
much harder then making driver that would allow you to hibernate to CD-RW
directly and to write data on that CD.

Basically doing that would not be so hard well I'm just kidding.

The simplest thing.
1. You El-torito driver.
2. XPe do regular boot from El-torito CD.
3. Hiber file exist to back-up your ram size and it is empty (ready for
write).
4. EWF is protecting your driver and CD from writes.
5. You do hibernation.

Hibernation writes go around EWF protection and your driver should write
data that it get to empty portion of CD. Simple eh?

Regards,
Slobodan