go through steps to enable and install WSL

install Ubuntu through Windows store

launch Ubuntu through Window store
                                        create username and pw in Ubuntu
                                        sudo apt update and sudo apt upgrade
                                        sudo apt install make
                                        sudo apt install gfortran
                                        sudo apt install libx11-dev

install xming (avail on sourceforge)
                                        sudo mkdir /usr/hhirf
                                        add /usr/hhirf to $PATH in .bashrc
                                        add export DISPLAY=:0 to .bashrc
                                        test something with xwindows (eg sudo apt install grace)
                                        copy upak-src.tar.gz into linux home directory and unzip/untar (note windows folders are accessible under /mnt/c)
                                        edit Makefile to choose PTRSIZE=64, FENDIAN = -DLITTLEENDIAN, and generally use the linux/gfortran flags*
                                        sudo make (must use sudo as installing in /usr)



*in order to avoid a pretty crippling problem with banio, the following flags must be used:

export F77= gfortran
export OPT= -O
export FARGS= $(FENDIAN) -DGFORTRAN -fno-automatic -fsecond-underscore -fno-range-check
export CARGS= $(FENDIAN)
export ARFLAGS= -rvU
export FLIBS= -lgfortran -lgcc
export INSTALLDIR= /usr/hhirf