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I have two computers sitting very close to each other.

One is an older computer nearly constantly logged in via VPN to another network, and I use SVN to push/pull files from that other network and use a few other resources.

The other computer is my main development computer, and I prefer to keep it unconnected from the vpn.

What I would like to do is connect an external hard drive to both computers concurrently. As it would be seen as a physical drive on the system, the computer that is VPN'd in would still be able to access the files (update them from SVN, etc.) and the second computer would be able to use them as well.

Any suggestions? I don't think I can use a cheap NAS because the VPN locks out all network access (e.g. I cannot access the second computer). And I have yet to find a hard drive that will allow two computers to be connected at the same time.

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I don't believe the device you are asking for exists. A hard drive can only be directly connected to one system at a time. I have thought about it and have a couple of ideas/workarounds.

I'll try to list them in decreasing orders of craziness:

  1. Just break down and connect to the VPN from your development PC.
  2. Talk to IT and see if they can relax the restriction on your VPN so you can at least talk to your local network and use a NAS/Network share.
  3. Get a USB switch box to switch the drive between the systems. (No concurrent access, it is equivalent to unplugging/plugging the drive between the systems)
  4. Use a USB transfer cable between the systems. (It doesn't really share the drives; it just copies files between them. I think some cables may have a sync software so you could sync directories)
  5. Connect the computers using a Firewire cable. (I don't think this will work since it uses TCP/IP and I'll be the VPN will disable it)
  6. Share the drive over the Internet so you VPN connected computer can connect to it. (This would mean that it connects out of your Internet connection, through the VPN to your company, and back to your Internet connection. This would be ridiculously slow)
  7. Use some protocol other than TCP/IP to connect the two systems, since I doubt the VPN will disable that. I think you could still install NETBEUI on Windows XP.
  8. Replace the VPN connected system with a virtual machine running on your dev PC. Connect the VM to the VPN. Share the drive using the shared folders feature of the VM (I know both VMWare and VirtualBox both have this). The shared folders don't use TCP/IP so the VPN shouldn't affect them.
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One idea is to take one of those cheap NAS devices--one with both USB and network connections and hook the USB to the VPN machine and access the NAS via the network on the other machine. I have never tried this configuration, but it may be worth a try.

Good luck!

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typically on "cheap NAS devices" the USB is there to add USB storage to the NAS, not to add the NAS as USB storage to another computer. the typical NAS device is driven by an embedded OS and acts as a USB host. you'd need a NAS that can act as a USB slave as well. – quack quixote Oct 22 '09 at 16:52

As far as I'm aware, when a O/S mounts a file system/drive it must be exclusive. USB/eSATA drives definitely fall under this category - it's why you don't see enclosures with more than two ports.

FireWire does allow you to daisy-chain devices (most FireWire drives/enclosures have 2 ports) creating a network, which might allow you to simultaneously physically connect a single drive to two different computers, but AFAIK only one can mount the device at a time. I've never tried this, though.

Lester's idea of using 2 separate protocols (one over the network, one over USB) is probably your best bet.

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Apple's Airport Extreme lets you share an USB external hard drive through the network.

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A simple way, as I see it, is to connect your computers with a switch, create a VPN only for 2 computers of yours, connect the HD to one of them, and you are done.

However, if you want something more sophisticated, what you can also try to do is to use a HD which allows you to create an FTP server on it, as I guess the basic functionality you need is file usage. FTP in this case really has advantages over the method I mentioned above.

Once you've done that, you can create a smaller VPN of your own (Windows Vista and onwards for e.g give simple "click and select" options to do this in Control Panel -> Networks) only for your computers. You do not have to worry about overlapping or privacy infiltration of any sort between 2 VPNs (that's the basic idea of VPN right?) you will now have and hence you can rest assured that your main computer which you use for development work is detached from your company VPN and 'outside world'.

Use a router to grant IP and other addresses to your FTP server and you can use FileZilla (from the Mozilla people), which is a very simple FTP client. I did not even need 15 minutes to start using it properly.

And you're done.

I've never tried any of this but I'm pretty sure this will work.

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