Mounting Files and Devices as USB Mass Storage - Revision history

Error454: Added link to an open source node.js project that uses these details.

2011-03-16T00:36:39Z

Added link to an open source node.js project that uses these details.

Error454: Fixed section header and grammar

2011-03-06T05:13:55Z

Fixed section header and grammar

Error454 at 04:18, 5 March 2011

2011-03-05T04:18:43Z

Error454: initial page creation

2011-03-05T04:17:00Z

initial page creation

New page

= Mounting Files and Devices as USB Mass Storage =
==Background==
Devices running WebOS use a usb mass storage driver written by Mike Lockwood in 2008. The driver source can be found in the following location in the source tree: 
linux-2.6.24/drivers/usb/gadget/f_mass_storage.c

This driver calls '''DEVICE_ATTR''' to create a file named "file" in sysfs. When the sysfs entry is read, the function '''store_file()''' is called within the driver. This function will mount the file or device that is passed in.

==Mounting Examples==
The following examples illustrate how to use this file, you must be root since the "file" entry has permissions 644.

'''Mount /media/internal''' 
echo /dev/mapper/store-media > /sys/devices/platform/musb_hdrc.0/gadget/gadget-lun0/file

'''Create a 256 MB image and mount it''' 
dd if=/dev/zero of=/media/internal/test.img bs=1M count=256 
echo /media/internal/test.img > /sys/devices/platform/musb_hdrc.0/gadget/gadget-lun0/file 

==Applications==
There are numerous applications that could benefit from using this feature. Many game consoles write to generic fat16/32 partitions, unfortunately they typically want to format the entire partition for their use. Using this method, a game console CAN format the entire partition (2nd example above) without wiping out the entire partition.

← Older revision		Revision as of 00:36, 16 March 2011
Line 17:		Line 17:
	==Applications==		==Applications==
	There are numerous applications that could benefit from using this feature. Many game consoles write to generic fat16/32 partitions, unfortunately they typically want to format the entire partition for their use. Using this method, a game console CAN format the entire partition (2nd example above) without wiping out precious user data.		There are numerous applications that could benefit from using this feature. Many game consoles write to generic fat16/32 partitions, unfortunately they typically want to format the entire partition for their use. Using this method, a game console CAN format the entire partition (2nd example above) without wiping out precious user data.
		+
		+	==Sample Service==
		+	A node.js service for WebOS 2.x that implements the base functionality to mount user-specified files can be found [http://gitorious.org/usb-mass-storage-tools-service here]

@@ Line 1: / Line 1: @@
 ==Background==
 Devices running WebOS use a usb mass storage driver written by Mike Lockwood in 2008.  The driver source can be found in the following location in the source tree:<br>
 linux-2.6.24/drivers/usb/gadget/f_mass_storage.c
-This driver calls '''DEVICE_ATTR''' to create a file named "file" in sysfs.  When the sysfs entry is written to, the function '''store_file()''' is called within the driver.  This function will mount the file or device that is passed in.
+This driver calls '''DEVICE_ATTR''' to create a file named "file" in sysfs.  When the sysfs file entry is written to, the function '''store_file()''' is called within the driver.  '''store_file()''' will mount the file or device that is passed in as an argument.
 ==Mounting Examples==
-The following examples illustrate how to use this file, you must be root since the "file" entry has permissions 644.
+The following examples illustrate how to use this special file, you must be root since the "file" entry has permissions 644.
 '''Mount /media/internal'''<br>
@@ Line 17: / Line 16: @@
 ==Applications==
-There are numerous applications that could benefit from using this feature.  Many game consoles write to generic fat16/32 partitions, unfortunately they typically want to format the entire partition for their use.  Using this method, a game console CAN format the entire partition (2nd example above) without wiping out the entire partition.
+There are numerous applications that could benefit from using this feature.  Many game consoles write to generic fat16/32 partitions, unfortunately they typically want to format the entire partition for their use.  Using this method, a game console CAN format the entire partition (2nd example above) without wiping out precious user data.