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

Doug Lee dgl at dlee.org
Wed Apr 6 17:51:09 UTC 2011 

Security wise, there is no logical difference besides speed of
transfer between a normal read-only mounted USB drive and a read-only
mount of what I'm talking about on the client side.  Read-only USB
mounts have been working out, just slowly.

On Wed, Apr 06, 2011 at 10:41:17AM -0700, Mike Freeman wrote:
I should think you'd have the same security concerns (not from your point of view but from Corporate) even if you *did* have a dual-ported USB drive.  Think you'll just have to obtain a memory stick your clients have approved of and switch back and forth.  If nothing else, it'll be good exercise jumping up and down to insert on a tower as I have under my desk.

Incidentally, in my environment, it's like pulling hens'-teeth to get an "approved" USB thumb drive.


Mike Freeman
sent from my iPhone


On Apr 6, 2011, at 10:19, Doug Lee <dgl at dlee.org> wrote:

> 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
>>> 
>>> _______________________________________________
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> 
> 
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>> -- 
>> 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
> 
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> 
> 
> 
> 
> 
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> -- 
> 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
> 
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-- 
Doug Lee                 dgl at dlee.org                http://www.dlee.org
SSB BART Group           doug.lee at ssbbartgroup.com   http://www.ssbbartgroup.com
"While they were saying among themselves it cannot be done, it was
done." --Helen Keller

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