Remote Access

From Northwestern University Center for Atom-Probe Tomography
Revision as of 20:16, 11 January 2007 by Karnesky (talk | contribs) (→‎SFTP: +winSCP +details on FZ +web)
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NUCAPT keeps all files on networked computers so that you are not dependent on any single facility workstation and so you can retrieve analyses remotely. Access is available in Cook Hall at Northwestern through Windows file sharing (SMB) & from anywhere via SFTP. Remote data analyses is also possible.


The following drives are available on NUCAPT PCs:

Mapped Drive Share location Description
H: \\arc\USERNAME Your home directory (where your analyzed data should go)
L: \\leap\data Where RHITs are stored
P: \\arc\public Shared files for the facility
S: \\leap\screenshots Screenshots on the LEAP computer


"Secure FTP" can be used from anywhere to retrieve data. This differs from FTP & not all FTP clients can access SFTP. Using SFTP ensures that your username/password and data are kept confidential. There are free clients for any platform.

Instructions to use the clients varies, but our site is at:


(standard port 22, use the same user/pass you use to login to an analysis workstation).

(Shell access over SSH is not permitted for most users, but SCP is.)

Suggested Clients


You should have access to:

Directory Description
~ Your home directory (where your analyzed data should go)
/u1/public Shared files for the facility

You might also have an incoming and/or an outgoing directory. Below these are subdirectories for other NUCAPT users. If you want to give a file to someone (say "isheim"), place it in the corresponding outgoing directory (say "~/outgoing/isheim"). The other user will be able to retrieve it from the relevant subdirectory in their "~/incoming". Currently, these are manually setup. Please let Rick know if you have files to trade with someone & need an incoming/outgoing directory.


In addition to the wiki and the literature database, NUCAPT users may put files into their ~/outgoing/www folders. This can then be accessed at

Remote Data Analysis


Two of the machines run UltraVNC, F/OSS for win32 which allows remote control. It is "usable" on any connection (even dial-up), but a 10Mbps connection or higher is preferred. There are a few limitations.


  • Color-depth and resolution are really limited if you want to use it interactively. The color depth could be a real problem if people have very complicated sets, as it could be more difficult to differentiate the different elements. It would be fine for samples with only a few elements.
  • There is some lag with the mouse, particularly if you use more colors. Any thing which needed precise control of the mouse (particularly setting ranges) takes some getting used to. It works if you are patient.
  • Either a remote user or a local user may use IVAS at any one time. Not both. By default, both the local and remote users will be able to use the keyboard/mouse/video at the same time--careless or miseducated users could end up trying to work when someone else was already logged in. Also, a remote user may inadvertently stay logged in, making others think the workstation is locked. Or the remote user may have a slow-enough connection that local users think they are done when they're not.
  • UltraVNC will run on the machines in the Seidman main lab. Transferring RHIT files will be slow until our network is upgraded. NUCAPT staff will optionally cache your data files for you on the machines for a fee.
  • The default settings of the program are some-what dumb, meaning you should follow the below method of installation.

Users have analyzed sets remotely, so it can be done. If this proves too inconvenient, you may want to rent IVAS instead.


  • Download UltraVNC. It is preferred that you get this from
  • Download rc4.key. It is preferred that you get this from
  • Install UltraVNC:
    • Double-click the UltraVNC-1.0-Setup_sf.exe file
    • Select "English" and press "OK"
    • Click "Next"
    • Select "I accept the agreement" and click "Next"
    • Click "Next"
    • Click "Next"
    • At a minimum, select "Viewer Only," which includes "UltraVNC Viewer" and "DSM Encryption Plugin" and click "Next"
    • Click "Next"
    • Select "Associate UltraVNC Viewer with the .vnc file extension" and click "Next"
    • Click "Install"
    • Click "Next"
    • Click "Finish"
  • Install the encryption plugin
    • Move rc4.key to C:\Program Files\UltraVNC
    • Move C:\Program Files\UltraVNC\plugin\MSRC4Plugin.dsm to C:\Program Files\UltraVNC


  • Click Start->All Programs->UltraVNC->UltraVNC Viewer
  • Settings:
    • In VNC Server, enter either:
    • Choose a connection speed. The lower speeds are recommended, even for faster connections, as they improve real-time responsiveness. However the lowest speeds may not have enough colors for you.
    • Select "Use DSMPlugin"
  • Click Connect
  • Login as NUCAPT\user where user is your NUCAPT username. The NUCAPT bit is important. Use your NUCAPT password.
  • If someone is logged in, please disconnect.
  • If you encounter the login screen, press "Ctrl-Alt-F4" to send a "Ctrl-Alt-Del" if needed & login and use the workstation as you normally would.