Hi, all, The problem is kind of long and complicated. I installed SL4.1 i386 on my cluster. All of the computers come with 2 xeon. The server is also connected to a SATA-SCSI raid through an LSI scsi card. At that time I could not connect to the raid successfully and I thought it was the problem of the OS, so, according to some suggestions, I changed the OS to SL 4.1 x86_64 version. But it turns out that the disk problem was mainly due to old SCSI card firmware. After updating the firmware, the raid problem was solved. However, when I tried to install Intel Compilers and MPICH2, I ran into big trouble. If I use icc and ifort, when I configured MPICH2, it will complain that icc cannot create C programs that run. If I use gcc instead of icc, I can make MPICH2, but the Fortran 90 example programs cannot be made. I looked into the error, it seems that icc and ifort created obj files with different object type than the library files made from compiling MPICH2. Due to my limited knowledge in these aspects, I finally gave up using Intel compilers. I turned into using gcc, g77 and g95 as my compilers, which generate much slower executables than using icc and ifort. To have a working MPICH2 with Intel compilers, do I have to reinstall my system with SL i386 version? Will >2TB disk partition be accepted by the i386 Linux? If both answers were 'yes', then what is the fastest way to reinstall SL 4.[12] i386 over SL 4.1 x86_64? Do I always have to totally remove the x86_64 Linux and install everything again? Thanks for your advices in advance. -- Sincerely, Kuo Kan LIANG Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, Taiwan