1. install g77 (refer to askubuntu.com)
   To install,first you need to download either the 32bit,or 64bit (click) g77.
   Open Terminal,and run the command(s) below:

For 32bit

tar -xzvf g77_x86_debian_and_ubuntu.tar.gz


cd  g77_x86_debian_and_ubuntu


chmod +x ./install.sh


./install.sh

For 64bit

tar -xzvf g77_x64_debian_and_ubuntu.tar.gz


cd  g77_x64_debian_and_ubuntu


chmod +x ./install.sh


./install.sh

run the command g77 to check

1. install lesstif instead of motif
   run the command:

   sudo apt-get install lesstif2-dev

2. install MDX
   run the command(s) below:

   tar -xvf mdx_NTR_35238_173_73.tar
   cd mdx_173_73
   mv Makemdx_g77 makefile

create a symbolic link for crt1.o and crti.o files

export LIBRARY_PATH=/usr/lib/x86_64-linux-gnu
sudo ln /lib/x86_64-linux-gnu/libgcc_s.so.1 /usr/lib/x86_64-linux-gnu/libgcc_s.so

make

run the command ./mdx to check

move the executable file mdx to $INT_BIN

1. enjoy it.