ICG Computing Guide
There are two computing environments available in the ICG: a Windows network supported by the university’s Information Services (IS) and a Linux network supported by group members. Our goal is that all users have access to both networks; unfortunately, given the reaction time for the university system, short term visitors may only be able to use the Linux network, or may be given a temporary account which does not keep files after logging out.
This document is primarily aimed at users of the Linux network. The primary trouble shooting of the Windows network should be done by IS, though if they are slow to react, then we can become involved. The primary contact points for reporting problems are:
IS service desk: firstname.lastname@example.org, x7777
The Linux administration in principle is shared between an IS Linux expert, a local scientific computing expert and the staff member with the computing portfolio. However, only a fraction of our time is available for these administration tasks. The default way to report problems is to email us at:
ICG Linux help: email@example.com
If you find a serious problem which you think requires our immediate attention, please let us know. If your problem is less urgent, it is better to send an email and we’ll try to respond when we have time.
The ICG has Jascha Schewtschenko to support scientific computing needs – for issues such as the following (not an exclusive list, but intended to give you an idea of the remit):
- you want access to the data available to the ICG and you are unsure of where to look, which data you need or how to use it (e.g. from SDSS or UKIDSS)
- you want help getting access to and adapting programs to run on COSMOS (Gary – see below – is also well placed to assist with this)
- you want assistance using any in-house scientific computing facilities
- you have difficulties getting any piece of science software working
Jascha also takes care of the webpages and is the person to speak to if you wish to set up your own.
SCIAMA help: firstname.lastname@example.org
For assistance with SCIAMA, turn to Gary Burton, the HPC support and SCIAMA administrator. You should also check the SCIAMA webpage for basic assistance and recent load information.
SSH from outside the University
Direct access to most machines is blocked from outside the University. However, it should be possible to directly connect into myfiles.port.ac.uk, and from there into other machines:
Note – do not run other programs on myfiles and use it only to connect further or access your files by scp.
Sciama is also remotely accessible.
Known hosts and SSH keys
It is useful to know that your ssh settings are kept in the .ssh subdirectory. Here, there is a file named known_hosts which keeps an ID tag of all the machines you log into with ssh. This is to prevent your communications from being intercepted by a third party. However, this tag can sometimes change for valid reasons, for example if the remote system is wiped, and you will be prevented from logging in. If this happens, you may have to delete the associated entry in the known_hosts file (you can do this with ‘ssh-keygen -R [ip address]’ ).
Also, sometimes it can get annoying putting in your password everytime you ssh or scp into the same machine. It can be useful to create an ssh key with the command ‘ssh-keygen -t rsa’. This creates two files, id_rsa and id_rsa.pub. Keep the id_rsa file in that directory (and private as it allows access to other machines!) Copy the id_rsa.pub file to your account on the remote machine and put it in the file ‘.ssh/authorized_keys’. You should then no longer require a password for ssh and scp.
The University offers a Virtual Private Network (VPN) service, allowing you to access the university network from outside. See the IT Help pages for more information. Note this is best supported on Windows and OS X.
The principal University mail for staff is run through GMail.
There are also group email addresses, including icg-all, icg-academic, icg-phd and icg-pdc. These are for the full group, lecturers, PhD students and postdocs, respectively. The group address are of the form [listname]-email@example.com, and your memberships can be found at Google Groups. You can also join and leave relevant groups through the Google Groups interface. The icg-social list is also available for announcing social events, and several research area-specific groups you may find out about from others in the department.
The ICG has several common printers, two located in the coffee room and one in 2.04. The default is the black and white printer, but there is also a colour one available and the photocopier can be used to print if the others are out of action. These all print double-sided.
These should be installed already. If needed, they can be installed via the instructions on the IT Help website or by IP address (22.214.171.124 and 126.96.36.199 and .15), or just ask for assistance.
Wireless via the eduroam network is available in most university buildings, but in some areas the signal is weak. It is the preferred way of connecting laptops, as its firewall is stronger. With Windows or Macs, it is straightforward to connect if you have a University account by following the instructions at the Portsmouth IT Help pages.
Connecting via Linux is sometimes more of a challenge, and may need a certificate pre-loading. Ask icg-computing (above) if you have trouble connecting.