Accessing the Statistical Computing Facility Remotely
In order connect to the SCF from
a remote (non-SCF) computer, you must have a
program which uses the secure shell (SSH) protocol
to communicate with other computers.
An SSH program alone will not allow you to
view graphics or images remotely.
For these purposes, you need an X Windows server
(sometimes known as X11)
either running natively on your computer, or via an
X Windows emulator.
Depending on your operating system, one or both of
these programs may already be installed on your computer.
The next section will explain how to obtain the
necessary programs if they are not already available, followed by
information on transfering files from the SCF to your local computer.
If you don't have a broadband connection,
you may find that the response when using X Windows remotely
may be too slow to be useful; but
with patience, you should
be able to access the SCF remotely with few problems.
Linux natively runs the X Windows system, and most Linux systems
have the ssh program available to securely connect to
2.2 Mac OS X
The ssh command is available through the Terminal application
(available in /Applications/Utilities/Terminal.app). For versions
of Mac OS X since Panther, there is
an installation package for X11 (X11User.pkg) on the Developer Disk.
2.3 Microsoft Windows
For ssh connections to the SCF, you can use a free program called
The putty executable is a single file, so it can be stored wherever
you find it convenient. When you execute putty, you'll see the
"Session Window"; type in a valid host name, and click the
"Open" button at the bottom of the window. At this point you'll be
prompted for a password. You also have the option of naming and saving
your session to make it easier to connect the next time.
Note that putty alone will not let you view graphics windows on
your remote computer - for that, you'll need an X Windows emulator.
If you have a CalNet ID, you can download Exceed from
UC Berkeley Software Distribution.
Note that if you wish to view graphics using putty you must set
up X Windows forwarding; click on the plus sign to the left of "SSH" in
the left hand pane, then click "X11" and check the box labelled
"Enable X11 Forwarding".
An alternative to the two programs mentioned above is the
Cygwin X Windows System. There are excellent instructions
for installing this software at Cygwin/X.
Basically, you first download a program called setup.exe, which
makes it possible to install a wide variety of software; you need choose
only four packages: xorg-x11-base, X-startup-scripts, inetutils and
openssh (Clicking on the View button in the setup.exe
window until it displays "Full" makes it easier to find the
packages you need). Once everything is installed you can double click on
c:\cygwin\usr\X11R6\bin\startxwin.bat to start the system.
A terminal window will
open, and you can use the ssh command as described below.
The User's Guide
covers just about every step of installation and use of the software.
3 The ssh command
If you're using a system with the ssh command, type
ssh -X username@hostname
to connect to an SCF computer.
The -X (upper case X) in the ssh command sets up the X11 Tunneling
necessary for displaying graphics.
4 File Transfer
If you want to print out your programs, listings and graphics on your
local printer, the easiest route is to copy the files from the SCF
computers to your computer and then to print them in the usual way.
The best way is to use a file transfer program on your local computer,
although other means are possible.
The command line scp command, described below, is probably
the best way to transfer files from one computer to another. If you'd
prefer a graphical client, programs like konqueror will accept the
sftp:// protocol. For example, if your username is s244x, you
would be able to access your files on the SCF computers by going to
4.2 Mac OS X
The command line scp command, described below, can be accessed
through the terminal (/Applications/Utilities/Terminal.app). Although
the finder doesn't directly support the sftp protocol, the freeware
program Fugu provides a
nice graphical frontend to the sftp command. To use Fugu, enter
your username and
an appropriate hostname in the Connect to: field; you'll be
prompted for a password when Fugu connects to the remote server.
Your remote files will appear in Fugu's right-hand pane, where
they can be dragged and dropped to a location of your choice in the (local)
4.3 Microsoft Windows
There are a number of free graphical file transfer clients available for Windows;
one nice and easy-to-use one is WinSCP.
After logging in to a remote system, you can
drag and drop files between the local and remote computers.
4.4 If All Else Fails
If you can't use the previously described methods, you can email
files from the SCF system to an email account of your choice.
One way is to use the command line program pine. To send files
as attachments with pine, enter the following command:
pine emailaddress -attach file1 -attach file2 ...
After hitting Return, type control-X to send the mail, and Y to
Note: There is a 5 Mb limit on attachments to emails sent through
the SCF. While this should pose no problems with text files saved from the
program editor, complex graphics may be too large to send through email.
Please check the size of the file you're sending (with the UNIX command
ls -l) before reporting a problem.
4.5 The scp command
The syntax for the scp command is:
scp username@hostname:file local-directory
You'll be prompted for your password; after entering it and hitting
Return, the file transfer will start.
To use wildcard patterns on the remote (SCF) machine, precede the
wildcard character with a backslash (\). For example to copy
all the pdf files from your SCF account, to the current directory on
your local computer,
use a command like:
scp username@hostname:\*.pdf .
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On 23 Jan 2008, 08:55.