---+ The Cryoelectronics Filesystem: Care and Feeding

This page describes how to create, repair, rebuild, and upgrade the filesystem on the cryo board's MicroSD card. Many of these steps should not be necessary, and are required for crash recovery only.

Digression: Device Files, Partition Files, and Mount Points

Linux permits you to interact with your MicroSD card on several levels:

1. as a raw device (e.g. /dev/sdg)
2. as a number of raw devices, each associated with a partition (e.g. /dev/sdg1 .. /dev/sdgx)
3. as a mounted filesystem (e.g. /media/microsd)

This page makes use of all three levels. There are a couple of critical things to note when following the directions on this page:

• Your hard drive uses the same device-file scheme as your flash cards. Particularly when you're using sudo with device files, remember that a typo (or a direction followed too literally) can clobber your hard drive.
• Device-file interaction should only be done when the MicroSD's filesystem is not mounted. Before writing to device files in /dev, you should ensure the associated filesystems are =unmount=ed.

Rebuilding the MicroSD card

Insert the MicroSD care into a reader (e.g. a USB adapter) on a Linux host. Your PC may or may not automatically mount the card's filesystem (depending both on the card's status and your PC's configuration.)

You must first determine the device To reformat the card (deleting everything on it), you must first determine

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This topic: CryoElectronics > WebHome > FilesystemBuilds Topic revision: r1 - 2010-08-07 - GraemeSmecher

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