On Tue, Jan 30, 2007 at 01:26:48PM +0100, Salvatore Benedetto wrote: > I was wondering if it is possible to increase the amount of system memory > seen by my FOX board by using a USB pen drive. Of course I know the memory > time > access would be slower, but my only concern is to increase the RAM size > seen by my embedded system. Then the only way forward is to add more RAM. > Does linux provide some mechanism to achieve this kind of configuration? The problem is that the memory on a USB drive is not directly addressable, i.e.: it can't be addressed by putting the correct address on the bus and read the content over the data lines. Instead, the kernel has to use the USB device stack to read the contents of the USB pen drive. One way to work around this would be to tell the kernel that it should copy the parts it needs from the pendrive into real RAM and write back unneeded parts back to the USB device. That's called swapping and that's the only way you can increase the amount of virtual RAM on your machine. Note that I would not recommend the use of a USB flash drive as a swap device. Especially when you're really low on memory, the system will trash and wear out frequently used sectors on the flash drive pretty fast rendering the system unusable. Erik -- They're all fools. Don't worry. Darwin may be slow, but he'll eventually get them. -- Matthew Lammers in alt.sysadmin.recovery
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