CentOS - Jul 2008 - share folder as USB mass storage device

Hi all!

Maybe I'm just being silly here, but I'm wondering if anybody has ever
used their computer for sharing files over USB. That is, the computer
pretends to be a USB mass storage device.

This could be useful for connecting to media players and such that
support you plugging a USB harddrive or memory stick.

Surely, somebody must have thought of this before :-D

regards,
  Bent

Bent Terp wrote:
> Hi all!
>
> Maybe I'm just being silly here, but I'm wondering if anybody has
ever
> used their computer for sharing files over USB. That is, the computer
> pretends to be a USB mass storage device.
>
> This could be useful for connecting to media players and such that
> support you plugging a USB harddrive or memory stick.
>
> Surely, somebody must have thought of this before :-D
>   
the USB interface only supports one 'master' (a computer) and all other 
devices are 'slaves'.    the master and slave controllers are quite 
different.  you'd need a special dongle to do this. 

and, of course, for the specific application you mention, you'd be 
sharing a raw block device, not 'files'...    most of those devices are 
expecting a FAT or FAT32 file system on the mass storage device, so 
you'd need to have a FAT(32) file system, either on a loopback file or a 
real disk partition, that you would unmount then share via this 
hypothetical SUB virtual block device.

> Maybe I'm just being silly here, but I'm wondering if anybody has
ever
> used their computer for sharing files over USB. That is, the computer
> pretends to be a USB mass storage device.
> Surely, somebody must have thought of this before :-D
Yes, Apple thought of it years ago. Plug a Mac/laptop to another Mac via 
Firewire (and I think USB too), boot it while holding down the T key 
(I'm pretty sure it's T), and it boots as a slave drive.

This was a standard feature used when you upgraded hardware and wanted 
to migrate your data across. Not sure if it works on Intel Macs, but 
don't see why it wouldn't.

However, this feature also relied on the BIOS. PCs don't have this. And 
if you just plugged two PCs together via USB, each end would be 
connected to a motherboard, or a PCI host card, not an actual device.

I have never seen this done in PC land, and it would probably require 
hardware/BIOS changes before someone implemented this in Linux.


-- 
Spiro Harvey                  Knossos Networks Ltd
021-295-1923                    www.knossos.net.nz