Department of Engineering

CUED teaching system - HPUX to Linux migration

Introduction

This document is being published to ensure awareness of necessary changes to the CUED teaching system among members of the department who may be affected by it.

This change has already been notified (via this letter) to Chairs of Subject Groups and discussed in a number of their recent meetings.

Background

There is a requirement to phase out the use of our existing cluster servers based on HP PA-RISC processors running HP's HP-UX operating system over the next couple of years, because:

• HP have announced end of life for PA-RISC platforms (see the FAQ answer here)
• support for HP-UX is being withdrawn by some of the vendors we depend on:
  • Mathworks (Matlab) announcement

After due analysis of the cost, performance, and software availability issues, it is intended to transition from the existing cluster servers to cluster servers running SuSe Linux Intel Xeon processors. This change is evolutionary rather than revolutionary as the DPO terminals and the three IDP robot-table workstations already run Linux and there is therefore considerable experience in using this environment for teaching.

Proposed timetable

• March/April 2005 (Easter vacation 2004/5):

  • preliminary trials of Linux cluster server associated with DPO terminals in the tw400 cluster

• May 2005 (Easter term 2004/5):

  • Availability of tw700 as example Linux cluster server (without any associated terminals) for testing by remote (ssh) login.

• Mid-June 2005 (Summer vacation 2004/5):

  • re-installation of a Linux cluster server managing the DPO terminals in the tw400 cluster, for testing over the vacation.

• August 2005 (Summer vacation 2004/5):

  • conversion of tw900 (cluster server for IDP lab in EIETL) to Linux cluster server (NB Permanent Change for October 2005)

• October 2005 (Michaelmas Term 2005/6):

  • reversion of tw400 cluster to existing PA-RISC system for normal teaching use. tw400 cluster will switch back to Linux cluster server in each vacation during the 2005/6 academic year.
  • NB EIETL cluster will remain managed by Linux cluster server throughout the year.

• Mid-June 2006 (Summer vacation 2005/6):

  • permanent transition of all teaching system cluster servers to Linux on Intel Xeon processors (NB Permanent Change for October 2006)

• Mid-June 2007 (Summer vacation 2006/7):

  • final removal of all PA-RISC systems running HP-UX from general access to members of the department.

Implications for members of the department

Software (in)compatibility

Compiled code (that is, almost all programs) that runs on the existing PA-RISC cluster servers running HP-UX will not under any circumstances work on the new cluster servers.

It is believed that recent versions of all the commercial engineering packages currently supported on the teaching system will be supportable on the new Linux servers.

The main concern, therefore, is with the use of "homegrown" software, particularly where there may not be a certainty that the source code is available, or that it will compile under modern conditions! It will be vital that staff whose teaching depends on such software ensure that it is tested and/or ported and/or replaced before October 2006 .

Similar issues apply to externally provided software (or software components - eg matlab toolboxes) that is not known to the computer systems group (in particular, if it has not been centrally installed, but lives in a member of staff's own filespace)

A separate issue will be teaching practicals that require students to compile their own source code (perhaps C, C++, or Fortran) - executables produced on a Linux-based cluster server based on Intel processors will not run on an HP-UX cluster server based on PA-RISC processors. This also applies to MEX files (compiled C, C++ or Fortran used from within Matlab).

This will be of particular concern during the academic year 2005/6 when tw900 will be Linux-based while the other cluster servers remain HP-UX-based. However, the problem has to some extent already had to be addressed with respect to the possibility of compiling code locally on the dpo terminals themselves (which also run Linux on Intel processors).

Finally, those who make use of the teaching system cluster servers as batch processors for research work may need to consider the possibility that their codes will need porting/re-writing/replacing in exactly the same manner.

Key dates

October 2005

Any teaching done on the IDP workstations in the EIETL which are managed by tw900, will need to be compatible with a Linux-based server running on Intel processors by October 2005 at the latest.

October 2006

All teaching software will need to run on Linux-based machines running on Intel processors (whether on the dpo terminals, or on their cluster servers).

June 2007

There will be no remaining facility within the department for running code that depends on PA-RISC processors and/or HP-UX operating systems.

Development support

Among the facilities being provided to assist in this transition:

• during each vacation between now and October 2006, at least one clearly marked cluster (probably the tw400 cluster) in the DPO will be converted to using a Linux cluster server, before reverting to its normal HP-UX cluster server during term-time.

• for those practicals that can usefully migrate to running on the DPO terminals rather than on the cluster servers, a remotely accessible DPO terminal development machine is available

Feedback and Advice

Any concerns raised by this or requests by members of teaching staff for support and help in dealing with the issues raised here, may usefully be directed in the first instance to the teaching-support email address.

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