Faking out the CF fixed/removable query bit

[jimt]

We would like to partition an off the shelf CF (Compact Flash). Current
practice says we must purchase a CF that IDs itself as FIXED, or we need to
buy a CF that has a utility program to change the CF itself so it will
identify itself as FIXED. Both approaches limit the choice of which CFs can
be used.

How about another approach? Would it be possible to do one of these?

- Ask MS to add a registry key that would force the OS to see the
particular CF or drive letter as FIXED media

- Provide a new filter driver that would intercept the query and force
this bit
to always be "FIXED"

- Modify the BIOS (if you have bios source) to intercept the query and
force
the status bit to always return as "FIXED"

Seems like this would really open the door to using any over the counter
CF's as partitionable media for XPe. This would be a great FP2007 feature,
imho

 

[KM]

jimt,

We would like to partition an off the shelf CF (Compact Flash). Current practice says we must purchase a CF that IDs itself as
FIXED, or we need to buy a CF that has a utility program to change the CF itself so it will identify itself as FIXED. Both
approaches limit the choice of which CFs can be used.

How about another approach? Would it be possible to do one of these?

- Ask MS to add a registry key that would force the OS to see the
particular CF or drive letter as FIXED media

Already been asked. You can add your vote. Send comments to the XPe team alias: wecrt at microsoft.com.

- Provide a new filter driver that would intercept the query and force this bit
to always be "FIXED"

There is an easier way. You can come up with a disk level filter driver for the CF that would ignore the removable bit.
This has been done in past (search NG for similar issues). A Ssample driver has been posted to xpefiles.com (Hitachi driver).

- Modify the BIOS (if you have bios source) to intercept the query and force
the status bit to always return as "FIXED"

XP doesn't use BIOS code to work with disks.

 

[jimt]

Thanks, KM. I have sent an email to MS requesting this feature, as you
suggested. We will not pursue the BIOS approach, thanks. Regarding the
filter driver...

I looked thru old posts. The closes match was from March 21, 2005
entitled "Will XPe ever support non-fixed CF boot devices?" The XPeFiles
filter driver (at
http://www.xpefiles.com/viewtopic.php?t=92&sid=531320d05ceeb4b66a27a978b49edafa)
is discussed. The last post regarding the use of this filter driver does
not look good:

Since we would be buying these CF's from any vendor, it won't be possible to
enumerate all possible future CF vendors in the .ini file in the XPe image
that we deploy today. The mechanism needs to report all vendor CF's as
fixed for our scenario.

Has the general case of forcing any CF to be viewed as FIXED been resolved
with the XPeFiles driver or other?

 

[Paolo Dematteis]

If you want to prepare a removable CF to be used with XPe the easiest way is
to come up with an old NT OS in a system that provide an on-board CF slot.
You'll be able to partition the CF with a primary active partition and than
you can format it as you need either in the NT OS or in Win2k/XP systems.

 

[KM]

jimt,

You can always give it a try. Keep in mind that the sample source code is included in that driver package posted on
www.xpefiles.com. This means you can always make it to work on your target with some modifications if necessary.

 

[jimt]

Thanks for the reply. That is an interesting approach. We could certainly
give this a try if such a system could be found. However we would
eventually like to do this within XPe or a PXE boot if possible, since a new
replacement CF may need to be formatted at a customer site to replace an old
one. (We would be booting off HDD or CF, one can rebuild the other).

Do you know what WinNT would have that supports the partition formatting
that WinXP does not have? I haven't seen this approach before in my NG
searches. Maybe you are referencing the DOS "FDISK" utility that is used to
partition the CF with FAT16 filesystem(s), as mentioned in the XPe Help
"Configuring the CompactFlash Device" page at
http://msdn.microsoft.com/library/d...p/html/xetbsConfiguringCompactFlashDevice.asp
where they say:

"You can also create an MS-DOS bootable floppy disk with a previous
version of Microsoft® Windows®, such as Windows 98 or Windows
ME. This boot disk includes fdisk. You can use fdisk to partition your
CompactFlash media."

I don't think we can use a FAT16 filesystem, if(?) that is what you were
thinking. Also it appears from the wording that the CF must still identify
as FIXED in order to use FDISK.

 

[jimt]

Yes, I think I can get it to work for a specific vendor's CF. But not the
general case because I can't enumerate all possible CF's we may want to use.
Oh well.

 

[Paolo Dematteis]

I never investigate what NT has that is XP doesn't. I think that NT doesn't
know what a removable device is because it doesn't support USB and such, so
it treat a CF as a normal disk.
I used this approach before to buy the PQI fixed CF ad I used 'windisk' from
desktop to prepare the CF with a primary active partition from that,
formatted with an NTFS compressed file system.

 

[jimt]

Hmm, did you ever try building more than one partition with 'windisk' on the
CF that identifies as removable media? The XPe help mentions that you can
create a primary partition for 'removable' CFs, but you can't have more than
one partition because the OS won't see it when you boot. Or so I understand
from reading the help file.

 

[Stuart Langley]

You're understanding is correct... Anything other than the primary partition
will not been seen on a removable device.

Regards,

Stuart

 

[Paolo Dematteis]

never tried!.

Hmm, did you ever try building more than one partition with 'windisk' on
the CF that identifies as removable media? The XPe help mentions that you
can create a primary partition for 'removable' CFs, but you can't have
more than one partition because the OS won't see it when you boot. Or so
I understand from reading the help file.