Hi, Please make sure that you install MPICH2 on Win7 from an admin command prompt (Please follow instructions in Section 9.4, not 9.1, of the MPICH2 installers guide - http://www.mpich.org/documentation/guides/ - to install MPICH2 on Win7). Uninstall any previous versions of MPICH2 before installing a new one. Ignore the error message from wmpiconfig for 64-bit installations. This is a bug and we haven't had the developer bandwidth to fix this issue. Try running an MPI program with multiple processes to make sure MPICH2 works for you. You can install MPICH2 32-bit on a 64-bit system (However we don't test this configuration often). There shouldn't be any major performance concerns, however if you want to send huge amount of data (in your MPI program) the 64-bit version will make it easier for you. Regards, Jayesh ----- Original Message ----- From: "Seokho Son" <[email protected]> To: [email protected] Sent: Sunday, December 16, 2012 2:00:33 PM Subject: [mpich-discuss] Questions regarding installation of 32/64bit MPICH2 on 64bit machines (os: win7) Hello, we are trying to establish a parallel programming environment using mpich2. [Specification of our environment] OS: Windows 7 (64bit) Two workstations: Intel CPU (64bit) Programming environment: Visual studio 2008 (64bit) We have two questions regarding mpich2 installation. We have tried 64bit mpich2 (version 1.4.1p1, 1.3.2, 1.3, 1.2), but all of them give an error message ("MPICH2 not installed or unable to query the host") in the wmpiconfig program. Also, when we click scan hosts in the wmpiconfig program, the items in the list of hosts are in gray which means error occurred. However, we could successfully execute a parallel program with 64bit mpich2 (version 1.3.2) on the 64bit machine even though this version still shows the error message Q1) So, we hope to know that we may simply ignore the error message. On the other hands, we experienced that most of 32bit mpich2 versions (version 1.4.1p1, 1.3, 1.2) work in our environment without any error message. Q2) Is it fine to use 32bit mpich2 on a 64bit machine? We hope to know if there is any disadvantage on this such as performance degradation. Thank you. Best regards, Seokho Son. _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss