---------------------------------------------------------------------- H H PPP CCC UK NATIONAL HPC SERVICE H H P P C C -------------------------- HHHHH PPP C x x provided by H H P C C xx EPCC and H H P CCC x x CCLRC Daresbury Laboratory ---------------------------------------------------------------------- HPCx User Mailing 055 29 October 2004 ---------------------------------------------------------------------- Contents ** Supercomputing ** Courses ** Change to password validation ** Attention PuTTY users! ** Bulletin Board ** "Capability Computing" ---------------------------------------------------------------------- Greetings-- SUPERCOMPUTING 2004 CCLRC Daresbury Laboratory and EPCC will have adjoining stands at the Supercomputing 2004 event in Pittsburgh, PA, starting on 8 November, and together we will be ensuring that HPCx has a presence. If anyone is going - please stop in and visit us. EPCC will be presenting a half-day tutorial, led by Lorna Smith and Mark Bull of the HPCx Terascaling team, on "Perfromance Scaling on Constellation Systems". The tutorial will draw on material developed for HPCx training courses as well as experience on other clustered SMP systems. ---------------------------------------------------------------------- COURSES At CCLRC Rutherford Appleton Laboratory Thursday Nov 25: Optimisation Techniques for the Power4 Processor This course will focus on tools and techniques for single processor optimisation on HPCx. The course will cover the architecture of the processors and memory system, profiling and hardware counter tools, getting the best from the compilers and Power4-specific tips and tricks. There will be hands-on sessions in addition to lecture material. We recommended that participants also attend the Performance Scaling course which will be held on the following day. Friday Nov 26: Improved Performance Scaling on HPCx This course will describe tools and techniques for improving the parallel scaling of applications on HPCx. The course will cover performance analysis tools, communication optimisation, decomposition techniques, parallel I/O, and mixed mode programming. There will be hands-on sessions in addition to lecture material. We recommended that participants also attend the Optimisation Techniques course which will be held on the previous day. To register for these courses, please use the standard form. http://www.hpcx.ac.uk/support/training/form.html ---------------------------------------------------------------------- CHANGE TO PASSWORD VALIDATION Until recently, accounts on HPCx were blocked after three failed attempts to log in. This limit has now been changed to ten. However, after each three failures, you will have to reconnect. We are confident that this change will not significantly affect the security of the service. On the other hand, looking at the query logs, it's clear that it has resulted a welcome reduction in the number of problems that people have with logging in. ---------------------------------------------------------------------- ATTENTION PuTTY USERS! Many people who access HPCx through a PC use the PuTTY program to make their connection to HPCx. The following has appeared on the PuTTY website: 2004-10-26 ANOTHER SECURITY HOLE, fixed in PuTTY 0.56 PuTTY 0.56, released today, fixes a serious security hole which can allow a server to execute code of its choice on a PuTTY client connecting to it. In SSH2, the attack can be performed before host key verification, meaning that even if you trust the server you think you are connecting to, a different machine could be impersonating it and could launch the attack before you could tell the difference. We recommend everybody upgrade to 0.56 as soon as possible. That's two really bad holes in three months. I'd like to apologise to all our users for the inconvenience. See: http://www.chiark.greenend.org.uk/~sgtatham/putty/ ---------------------------------------------------------------------- BULLETIN BOARD Did you know that the HPCx website includes a bulletin board? Go to: http://www.hpcx.ac.uk/support/bulletin/messages/board-topics.html It would be an exaggeration to say that there has been a lot of traffic there so far. The helpdesk is our major route for handling problems, but it has a strict query -> answer protocol. Perhaps more free-wheeling discussion, involving people from different projects as well as HPCx staff, might be productive. So this is an invitation to everyone to pay a visit to the bulletin board, to post something, and see if it can be a useful resource. ---------------------------------------------------------------------- "CAPABILITY COMPUTING" The latest edition of our newsletter, "Capability Computing", has been sent to everyone on our mailing list. If your copy hasn't arrived, please let us know. ---------------------------------------------------------------------- Regards --John ---------------------------------------------------------------------- Earlier mailings: http://www.hpcx.ac.uk/support/notices/index.html To be removed from the mailing list: log into your website account, go to the "Update" page, and click the "Opt out of user emails" field; then click "Commit update". -- John Fisher j.fisher@epcc.ed.ac.uk HPCx User Administration and Helpdesk HPCx: http://www.hpcx.ac.uk Helpdesk: support@hpcx.ac.uk Phone: +44 131 650 5029 Fax: +44 131 650 6555