[nfbcs] USB drive on two machines at the same time?

[Doug Lee]

The problem I'm trying to solve is this:  I frequently script at
company and government locations that will not allow me to connect my
laptop to the local network.  Some sites don't allow write access to
USB drives either.  I develop scripts on my laptop much of the time
because I have tools there for managing the process, but of course the
scripts must be installed on the machine at the location where I'm
working.

So the two-USB-connector drive idea would work like this:  I would
write code on my laptop and run an installer from the same drive to
install on the office machine.  The same can of course be achieved
without the extra USB connector just by moving the drive back and
forth between machines, but in rapid-turnaround testing situations,
which are frequent, that becomes much slower than my idea would be.

On Wed, Apr 06, 2011 at 12:07:52PM -0500, Steve Jacobson wrote:
Doug,

I think you are right, that just using two connections is going to be unreliable.  I would think that your best approach would be to share the drive on one 
computer and make it available to the other through a wireless network connection.  I assume that the problem with networks is that you don't want to be on 
a larger network and you may not have ethernet connections.  I know that Windows has a create wireless network wizzard that seems to be for sharing 
resources and devices as opposed to just connecting to a network, but I have never tried this.  Good luck.

Best regards,

Steve Jacobson


On Wed, 06 Apr 2011 12:56:38 -0400, Doug Lee wrote:

>I think any drive or device allowing simultaneous connections would
>have to be designed especially for this usage, because something has
>to arbitrate the simultaneous access, deal with caching issues, etc.
>You do highlight a curiosity I've long had though, about what would
>happen if I try two connection types at once as you suggest.  The same
>would apply to any drive with both a USB and a Firewire connector.

>On Wed, Apr 06, 2011 at 11:15:38AM -0500, Bryan Schulz wrote:
>hi,

>i suspect you would overload the drive with double the voltage but...
>if you have the drive to experiment with destroying,
>get a usb/esata external enclosure as newer laptops have the new esata
>port then one computer could connect by regular usb and the other
>computer could connect thru the esata cable.

>Bryan Schulz

>----- Original Message ----- From: "Doug Lee" <dgl at dlee.org>
>To: "NFB in Computer Science Mailing List" <nfbcs at nfbnet.org>
>Sent: Wednesday, April 06, 2011 10:02 AM
>Subject: [nfbcs] USB drive on two machines at the same time?


>>I'm not sure where best to ask this question, so besides actual
>>answers, I welcome pointers on where to send this one.  My excuse for
>>posting this here in the first place is that I need the device I'm
>>about to describe for scripting projects. :)
>>
>>I am looking for a USB drive, or better yet, a USB device that allows
>>a drive to be connected to it, that then allows the drive to be
>>plugged into the USB ports of two computers at the same time.  To each
>>computer, it would be a USB drive pretty much like any other.  I know
>>this issue is normally solved with a Network Appliance, but that is
>>not possible in my situation for security reasons.
>>
>>A specific example:  I want to plug this device into, say, a desktop
>>computer's USB port and a laptop's USB port at the same time, write
>>files to the drive from the laptop, and read them off the drive with
>>the desktop.  I'm even ok if the drive is mounted read/write by the
>>laptop but as read-only by the desktop.  (This would cover most
>>security issues I've encountered in my work, since most sites will let
>>you bring data into a machine but not write it back out of it.)  The
>>device must use USB connections, not Ethernet (Cat 5) connections.  As
>>a last resort if the two-USB idea doesn't exist, I could probably work
>>with something that allowed one USB connection and a simultaneous WiFi
>>connection, as long as the WiFi connection supports WPA2.
>>
>>I notice one technical detail that may present a problem:  The OS on
>>the desktop, in my above example, would somehow need to know not to
>>cache the drive data aggressively, even if it mounts the drive as a
>>read-only device, because the laptop could change the data at any
>>moment.
>>
>>Does such a device exist anywhere?
>>
>>-- 
>>Doug Lee                 dgl at dlee.org                http://www.dlee.org
>>SSB BART Group           doug.lee at ssbbartgroup.com
>>http://www.ssbbartgroup.com
>>"The U. S. Constitution doesn't guarantee happiness, only the pursuit
>>of it. You have to catch up with it yourself." --Benjamin Franklin
>>
>>_______________________________________________
>>nfbcs mailing list
>>nfbcs at nfbnet.org
>>http://www.nfbnet.org/mailman/listinfo/nfbcs_nfbnet.org
>>To unsubscribe, change your list options or get your account info
>>for nfbcs:
>>http://www.nfbnet.org/mailman/options/nfbcs_nfbnet.org/b.schulz%40sbcglobal.net


>_______________________________________________
>nfbcs mailing list
>nfbcs at nfbnet.org
>http://www.nfbnet.org/mailman/listinfo/nfbcs_nfbnet.org
>To unsubscribe, change your list options or get your account info for nfbcs:
>http://www.nfbnet.org/mailman/options/nfbcs_nfbnet.org/dgl%40dlee.org

>-- 
>Doug Lee                 dgl at dlee.org                http://www.dlee.org
>SSB BART Group           doug.lee at ssbbartgroup.com   http://www.ssbbartgroup.com
>"Believe, when you are most unhappy, that there is something for you
>to do in the world. So long as you can sweeten another's pain, life is
>not in vain." --Helen Keller

>_______________________________________________
>nfbcs mailing list
>nfbcs at nfbnet.org
>http://www.nfbnet.org/mailman/listinfo/nfbcs_nfbnet.org
>To unsubscribe, change your list options or get your account info for nfbcs:
>http://www.nfbnet.org/mailman/options/nfbcs_nfbnet.org/steve.jacobson%40visi.com





_______________________________________________
nfbcs mailing list
nfbcs at nfbnet.org
http://www.nfbnet.org/mailman/listinfo/nfbcs_nfbnet.org
To unsubscribe, change your list options or get your account info for nfbcs:
http://www.nfbnet.org/mailman/options/nfbcs_nfbnet.org/dgl%40dlee.org

-- 
Doug Lee                 dgl at dlee.org                http://www.dlee.org
SSB BART Group           doug.lee at ssbbartgroup.com   http://www.ssbbartgroup.com
"Innovation is hard to schedule." -- Dan Fylstra