Hide RPi boot partition on Windows


9 posts
by rawsock » Fri Nov 02, 2012 9:28 pm
Hi,

For the last several days I'm trying to make RPi and Windows recognize different partitions on the SD card. What I would like to achieve, is to be able to collect some scientific data when RPi is booted and running and write it to the second partition of the SD (UDF filesystem, works for both Linux and Windows). Then, insert this card to a Windows machine and be able to directly read the files in the second partition. I can't use single partition, since RPi boots only from FAT and I need to collect data larger than 4GB.
The problem is that RPi can only boot from the first partition and at the same time Windows only sees first partition of a removable device. I tried several different approaches, including hidding a partition, changing order, type, etc., but the result is always the same (RPi boot and Windows always see the same partition).
I know that there are some hacks to force Windows to read the second partition, but they are dirty and works only on the hacked machine. I could use ext2 filesystem, but I would need ext2 drivers to be installed on the target Windows machine, which, again is not the ideal solution I'm looking for.

Any ideas?
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by aaa801 » Fri Nov 02, 2012 10:12 pm
Why not use a usb stick for the files?

Found a solution,

http://code.google.com/p/grub4dos-irene ... 1.0512.rar

run that
"Parts Manage" > "ReFormat USB disk" > choose the dropdown option for your new first partition > click "Set Accessible"
Enjoy
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by rawsock » Sat Nov 03, 2012 7:40 am
That would require switching partitions everytime I switch SD between RPi and Windows. And it requires additional software on Windows machine. If would be easier just to do it on ext2 and forget, but again this is not what I'm looking for.

The reason for not using a pendrive is that finally I'll be using model A which takes less power, and I need USB for another device.
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by Joe Schmoe » Sat Nov 03, 2012 7:51 am
Heh heh. I suppose the argument is that if you are going to allow "additional software" on the x86 box, then that "additional software" might as well be Linux - which would solve all your problems.
Never answer the question you are asked. Rather, answer the question you wish you had been asked.

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by rawsock » Sat Nov 03, 2012 7:54 am
Yes but there are ext2 utilities for Windows. No need to reboot :).
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by ghans » Sat Nov 03, 2012 8:32 am
Perhaps create a third exFAT partition ? Or even a NTFS one (use ntfs-3g on the Pi) ?

ghans
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by Joe Schmoe » Sat Nov 03, 2012 8:47 am
ghans wrote:Perhaps create a third exFAT partition ? Or even a NTFS one (use ntfs-3g on the Pi) ?

ghans


Reportedly, the problem is that Windows (all flavors, apparently) won't recognize (i.e., assign a drive letter to) any partition other than the first (on "removable" media). So, any sort of "create another partition" solution is a non-starter.

ISTM that the only acceptable solution would be to make the one FAT partition very large, then somehow finesse the file size limitation issue.
Never answer the question you are asked. Rather, answer the question you wish you had been asked.

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by rawsock » Sat Nov 03, 2012 8:47 am
Why do you expect third partition to be recognized differently then the second one? Windows is just not going to see it natively.
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by rawsock » Sat Nov 03, 2012 8:54 am
Joe Schmoe wrote:ISTM that the only acceptable solution would be to make the one FAT partition very large, then somehow finesse the file size limitation issue.


This is my backup plan (rotate the data log file every 4GB in software).
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