[TriLUG] file backed storage widget

[Brian Henning]

It's worth mentioning that if you do happen across a plain A-to-A cable 
(with no little box of electronics somewhere along its length), plugging 
two hosts together will not simply not work, but probably permanently 
destroy one or both USB ports as well (by shorting out the power or data 
lines, I forget which).

Note that this is not the voice of personal experience, but something I 
heard along the way.  Hopefully I'm not perpetuating a false rumor. :-)

~B

Aaron S. Joyner wrote:
> 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

-- 
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Brian A. Henning
strutmasters.com
336.597.2397x238
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