CERN-FOCUS-2000-010

Geneva, 8 December 2000

M E M O R A N D U M

A/To: FOCUS

De/From: LHCb Computing Group

Concerne/Subject: LHCb position concerning support for physics software on Windows+Intel

___________________________________________

LHCb fully supports the choice of Linux+Intel as the main development and production platform for offline physics software.

LHCb recognizes the importance of a second development platform to ensure the correctness and portability of the software.

LHCb has chosen Windows+Intel as its second development platform. The following are some of the reasons for this choice:

• It is highly likely that Windows will exist in at least part of the online system (e.g. to control commercial hardware, such as power supplies, which is sold with OPC drivers). Since we are planning to share many tools between the online and offline environments (e.g. event display, fitting package), we feel that we should not drop support for Windows in our offline software.
• Windows is widely available in the majority of our collaborating institutes. Therefore there is no need for any additional hardware investment in a second platform. We believe it is advantageous to provide software that can be used on the two currently most widely available operating systems.
• Many of our core developers are convinced that the Visual Studio development environment greatly enhances their productivity, and are reluctant to accept the loss in personal productivity that would result from moving to a set of less well integrated tools on a different platform.

LHCb acknowledges the choices of the other experiments and recognizes that it is unreasonable to expect IT/API group to maintain software on Windows exclusively for the benefit of LHCb. We believe that, given the Windows experience of our core development team, it should be possible for us to port ourselves to the Windows platform the software that we need, without a serious impact on our very limited manpower resources. However, we request that:

· IT/API group takes all reasonable measures when making technology choices (e.g. choice of windowing toolkit) to ensure that these choices do not prevent the porting of software to the Windows platform.

· IT/API group distributes the Windows port through the same distribution channels as the officially supported code

· Any code modifications required for the port will be promptly accepted for inclusion back into the official code base

· Efforts will be made to avoid wherever possible code constructs which are known to cause problems to the Visual C++ compiler

Provided the above requests are met, LHCb is forced to accept the IT/API proposal to drop official support for physics software on Windows.