[TriLUG] file backed storage widget

[Aaron S. Joyner]

Ralph Blach wrote:

>I have two systems, one a knoppix laptop, occasionally, and the other is a
>knoppix
>system with a usb key.
>
>I noticed that the modern 2.6 kernels have a file backed storage widget.
>
>On my Knoppix system, I use the usb key to store my setup and files.
>
>With the propper cables could I connect the usb connector on the knoppix
>system
>to the my Linux host, bring up the file backed storage widget, and have
>the file backed storage widget act as the usb file system for the knopix
>system?
>
>knoppix-----------usb------------linux-host- with file backed storage widget
>
>
>thanks
>
>Chip
>  
>
Okay, let me prefix this by saying that I know nothing of this 'file
backed storage widget' in the 2.6 kernel, but I do know a bit about USB
hardware.  Any USB device must act as either a host, or a device.  You
can think of it as acting like a computer, or acting like a usb key. 
This is a hardware level function we're talking about, not merely a
software convention of who decides to talk in what way.  Thus, a
hardware device (ala the usb port on a computer) designed to accept
connections from devices (such as usb keys) can't be connected directly
to another hardware device of the same type.  This is reflected in the
cabling standards, as well.  You may find that you won't normally see
USB A <-> A cables, only A<->B cables, etc.  USB hubs have a USB B port
on the back and USB A ports on the front (although front/back my be
figurative, in some designs), for this same reason.  If you find a USB A
<-> A cable, it's actually a converter, which acts as a device in the
middle for both sides.  These are usually billed as "USB File Transfer
Cables" or some such, and are intended to connect two computers together
as you describe.  They're a fair bit more complicated than a simple
cable, so expect them to cost upwards of $15-20 (ala a USB serial
adapter kind of cost range).  With such a device, the setup you're
describing is not beyond reason from a hardware perspective.  With only
a simple cable, it is not.

Let us know how it works out,
Aaron S. Joyner