Wednesday, September 19, 2012

Some geek info

I'm posting this info because both of these computer things cost me hours of grief and I'm hoping by posting them and having them google searchable, others will not suffer.

(1)  Upgrading to mac-osx lion, I found that the x2go client would not properly detect the mac keyboard.  Go to settings, keyboard, and type in pc104 where it is default pc105.   This fixes the problem (at least for me it did).

I still have a few problems with x2go.  But logging into my linux box from my mac, I find that kde4 and LXDE run fine.  The other window managers still give me trouble and crashed frequently.

(2) Writing a program in gfortran or g77  in ubuntu 12.04:

I had trouble running the program if the program requires over 2Gb of RAM.  The computer has 6GB so this should not cause trouble.   This caused me half a day of grief.  The solution was first, to include the compile flag (this is expected)


But even then, when the program wanted more than 2Gb, the program would compile but not link.   I then installed binutils-gold which swaps out the linker for a newer (and faster) version, and it works.

I'm still hunting down some bugs, but for some reason when my program takes more than 2Gb of memory, I'm still getting errors when I compile using gfortran.  But it works fine under g77, so maybe I'll just stick with that.   If anyone cares to debug, here is my info:

$ gfortran -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5)

$ g77 -v
Reading specs from /usr/lib/gcc/x86_64-linux-gnu/3.4.6/specs
Configured with: ../src/configure -v --enable-languages=c,c++,f77,pascal --prefix=/usr --libexecdir=/usr/lib --with-gxx-include-dir=/usr/include/c++/3.4 --enable-shared --with-system-zlib --enable-nls --without-included-gettext --program-suffix=-3.4 --enable-__cxa_atexit --enable-clocale=gnu --enable-libstdcxx-debug x86_64-linux-gnu
Thread model: posix
gcc version 3.4.6 (Ubuntu 3.4.6-6ubuntu5)

(the old linker) 
$ld.bfd -v
GNU ld (GNU Binutils for Ubuntu) 2.22

(the new linker) 
$ ld -v
GNU gold (GNU Binutils for Ubuntu 2.22) 1.11

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