Computing Service

Computing Service Newsletters

Computing Service Newsletter 231 (January 2007)

Central Services News

CUS closure

Users are reminded that, as announced in the last Newsletter, the Central Unix Service will close down on 1 October 2008. The intention is that the majority of the functions of the CUS should be consolidated into other services, including an enhanced PWF Linux service.

The closedown schedule will be as follows:

  • 1 October 2007: no more new CUS accounts will be created
  • 1 October 2008: CUS will be closed down. Email addressed to CRSid@cus.cam.ac.uk will be redirected to CRSid@cam.ac.uk, and web requests to http://www.cam.ac.uk/~CRSid/ will be redirected to http://people.pwf.cam.ac.uk/CRSid/
  • 1 October 2010: mail and web forwarding will cease.

It is expected that very few people will need to open new CUS accounts from now on, but there may be special cases such as someone joining a research group with a heavy existing commitment to CUS. Anyone wishing to open a new CUS account should contact ids@ucs.cam.ac.uk stating their case.

Advice on migrating from CUS has been published at http://www.cam.ac.uk/cs/unix/cusmigration.html and includes sections on

  • Mail
  • Files and filenames
  • File permissions
  • Personal web pages
  • Unix systems and utilities
  • Applications

Closure of Pelican

The Pelican archive service became read-only on 2 January 2007. All routes by which data may be uploaded to Pelican have been blocked. Pelican will close altogether at the beginning of 2008. Please be sure to retrieve any files you need before the end of 2007. If you have finished with your Pelican filespace and are happy for it to be cancelled, please send a message to ids@ucs.cam.ac.uk asking for cancellation.

For further information, see http://www.cam.ac.uk/cs/instadmin/pelicanend.html

Printing on PWF printers: the Common Balance and online payment

The PWF printing Common Balance scheme allows users to pre-pay into a common credit system for printing at any member institution, rather than having to maintain a separate balance at each institution. It has the further advantage that payment may be made online, out of office hours if required, as well as in person.

Printing to PWF printers may be from a PWF workstation (in a Computing Service room or a Managed Cluster at an institution). You can also print from any Windows XP system on the CUDN to any PWF printer (with a very few exceptions), using the iPrint facility (http://iprint.pwf.cam.ac.uk/). See the earlier article in this Newsletter about using iPrint via the Lapwing wireless service. The charging arrangements for a given printer are independent of whether you are using iPrint or not.

With the addition of Law in December 2006 and the Moore Library in January 2007, there are now eight Managed Cluster institutions, as well as the Computing Service, using the Common Balance for their printers. The clusters concerned are at the Computer Lab, Education, English, History, Homerton College, Moore Library, Law, and MML (including the Philosophy PWF printers); the list thus includes all departmental PWF clusters on the Sidgwick Site.

Payment for printing on all printers within this scheme can be made at Computing Service Reception, at the LLCC (top floor of the Raised Faculty Building on the Sidgwick Site), or at certain institutions (for members of the relevant institution only). Payment can also be made online by debit or credit card using the PWF eCredit application on any PWF Windows station within the participating institutions (including all public Computing Service rooms).

The PWF eCredit online payment system has been very successful since its launch last August. Initial restrictions on hours of use were removed in September, and payments are now accepted at all times. This facility is available only for printing on Common Balance printers.

Changes to PWF group filespaces

The changes to PWF group filespaces announced in earlier Newsletters took place on 20 November 2006. Details are described at http://www.cam.ac.uk/cs/news/pwfsocchange.html

Registered University Society websites are now available at the URL http://www.societies.cam.ac.uk/. The website of any unregistered Society or other group ( which was previously in the SOC directory) with a public_html directory is now available at http://groups.pwf.cam.ac.uk/ .

The new index of the Society web sites is at http://www.societies.cam.ac.uk/index.html Redirections are in place from all the old names to the new URLs.

PWF filestore problems in November

The Computing Service deeply regrets the effects of the problem in the week beginning 13 November affecting the PWF-HOME4 volumes (and therefore those users whose CRSids begin with letters in the range S-Z, and course and visitor identifiers).

The PWF is designed to provide a reliable service. Its filestore is constructed with redundant equipment to avoid single points of failure. The disk storage itself is built as RAID arrays so that a failure of a disk should not cause loss of data. The disks are regularly backed up to tape to provide a means of recovering data, should a failure of the file store occur for which the RAID array did not provide protection.

The problem appears to have arisen because a disk failure was followed by corruption of disk data, by some means that is not understood; this led to the two user volumes becoming unavailable, with a third subsequently being taken out of service because of data corruption. External advice to restore from tape was followed. As the restore was progressing very slowly, an alternative, non-standard but faster method of restore was devised, and this led to restoration of service to all users on the Wednesday.

More details of the chronology of the event, of the investigations into its cause, and of future developments planned to minimise the risk of recurrence, can be found in the article in the Computing Service announcements newsgroup (http://www.cam.ac.uk/cgi-bin/wwwnews?grp=ucam.comp-serv.announce&art;=1509).

Working with your PWF files remotely [headline article]

Most access to PWF filespaces is from users at PWF stations in public rooms or in College or Departmental Managed Clusters. However, it is now quite common for PWF users to want to access and manage their PWF filespace from a non-PWF machine, for instance in a College room. This applies particularly to users who do most of their work on their own machine but use their PWF filespace for backup, and to people running Society and group filespaces, and may also apply to any regular PWF user who happens to need access to their filespace at a time when it is not convenient to go to a PWF room.

This article describes the different ways this can be done, and which methods are more convenient for which purposes.

Note that you cannot in general run PWF Windows or Macintosh applications remotely. To run Microsoft Office on PWF Windows, for instance, you do need to be using a PWF workstation. Linux applications are available via the remote access PWF Linux servers and can, with certain restrictions, be run from non-PWF machines.

The following methods are available for remote access to your PWF files (more detailed instructions are at http://www.cam.ac.uk/cs/pwf/fsaccess.html)

(a) mount your PWF filespace directly on your desktop. This is very straightforward for Macintosh users within the cam domain (see the instructions at http://www.cam.ac.uk/cs/pwf/macafp.html). It is technically possible for some Windows users (at present only within institutions that either have PWF managed clusters or belong to the Colleges' PWF club).

(b) Use the NetStorage web interface (https://netstorage.pwf.cam.ac.uk/netstorage) to list your PWF files, transfer them between the PWF and your local machine, delete, rename, or move them. You can also modify access rights via this interface. You can display but not edit the contents of some types of file (depending on the capabilities and configuration of your web browser).

(c) Use a file transfer client (e.g. WinSCP or MacSFTP) to do most of the above (but not to change rights, or normally to see contents without actually transferring the file). See http://www.cam.ac.uk/cs/filetransfer/ for details; the required name is sftp.pwf.cam.ac.uk. You can also use plain FTP (not recommended), in which case connect to home.pwf.cam.ac.uk for your home filespace or shared.pwf.cam.ac.uk for University Society filespaces.

(d) Use the NetStorage WebDAV interface (instructions for Windows are at http://netstorage.pwf.cam.ac.uk/webdav.html) to make your PWF filespace accessible directly to your local machine; this allows you to do all the above and also to edit your files directly on the PWF. WebDAV access to NetStorage does not work on Macs at present.

(e) Login to one of the remote access PWF Linux servers (ssh to linux.pwf.cam.ac.uk) and use the Linux command-line interface. This allows you to manage your files (delete, move, rename, set rights and examine your quota) and to edit files directly provided there is a Linux application which can handle them (e.g. to edit a Word file you could use Open Office). You cannot, for instance, display a graphical file, or use a graphical interface for file handling, unless you run an X server on your own system; this option is not discussed here.

Which method is most convenient for you will depend on exactly what you need to do, on your own machine and its configuration, and on whether you prefer a Web interface or are happy with an SFTP client or with remote Linux.

  • To list your files and do basic management (move, rename, delete), any of the above will work.
  • To move files between the PWF and your local machine, any except (e) can be used. Methods (a), (c) and (d) allow you to use drag-and-drop to transfer files; method (b) is generally slightly more complicated.
  • To display and edit the contents of certain types of file, (a) or (d) will work; (b) allows you to display the contents of certain types of file but not to edit them (without transferring to your local system and transferring back again). (e) allows you to display and edit any file for which a suitable Linux application is available on the remote server.
  • To set access rights you can use (b) or (e).
  • To check your quota and filespace usage remotely the only method available is (e); (b) allows you to look at your quota but not your usage.

All the methods listed can be used for Society filespaces as well as personal ones.

Further information is at http://www.cam.ac.uk/cs/pwf/fsaccess.html

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Requests for PWF software for next academic year

The following notice will appear shortly in the University Reporter:

Public Workstation Facility - Applications and teaching software for the academical year 2007-08

This notice is addressed to all those who currently use or who are planning to use the Public Workstation Facility (PWF), including Managed Cluster stations in departments and colleges, to support their teaching whether for organized courses or for teaching which depends more generally on applications on the PWF.
Requests for new application software or for new versions of application software for all three workstation platforms (Linux, Macintosh and Windows) are needed by the Computing Service by the end of Full Lent Term (Friday, 16 March 2006). They should be submitted either by email (pwf-manager@ucs.cam.ac.uk) or in writing to the PWF Manager, University Computing Service, New Museums Site.
Software for which requests are received later than this date will not necessarily be installed in time for the start of the Michaelmas Term. It would also be helpful to be informed of any software that is no longer required. The list of software which the Computing Service plans to make available for the start of the Michaelmas Term will be announced on the Computing Service web page http://www.cam.ac.uk/cs/pwf/upgrades.html by the division of the Easter Term.
The programme of installation of the new software will need to start immediately after the end of Full Easter Term, in order that it can be completed on time. Those teaching during the Long Vacation should note that the installation of new versions of PWF software during that period may have implications for them.
The full set of applications for 2007-08 is intended to be available from Monday 3 September. This time-scale will enable those whose teaching depends on these applications to check that they work correctly, update course notes and allow for any necessary remedial action to be taken before the start of the Michaelmas Term.
Those requesting software, whether new applications or upgrades to existing software, are asked to consider the budgetary implications of their requests for themselves and Managed Cluster institutions.

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The title of this document is: Computing Service Newsletter 231: Central Services News
URL: http://www.cam.ac.uk/cs/newsletter/2007/nl231/central.html