IMPORTANT: Windows 95/98/ME does a remarkably poor job of process load balance. If you change the focus from the cygnus window, performance will immediately drop by at least 1/3, and the timings will be inaccurate. It is recommended that you leave the focus on the install window throughout the entire install procedure. This is not necessary for Windows NT/2K/XP. ATLAS requires unix-style make and /bin/sh commands in order to install on a windows system. A fairly complete unix-style environment is available free of charge at: http://www.cygwin.com/ From this website, you can download the package, get installation instructions, etc. You will want to download the "full" version of cygwin, which includes compilers, shells, make, etc. Be sure you get all the compilers you are interested in (ATLAS requires gcc, and you will probably want g77 or gfortran as well). The cygwin installation is quite simple, involving downloading an executable and installing with Windows' usual install procedure (you can remove it from your machine with Windows' ADD/REMOVE if you later decide you don't want it). After this is done, simply follow the instructions given in atlas_install.pdf, running all command in a cygnus window. By default, ATLAS will be compiled with the gnu gcc compiler that comes with cygnus. Gnu gcc provides better ATLAS performance than does MSVC++, Watcom C, or Intel icl, so we recommend that you leave gcc as the compiler the main compiler. If you compile the interface routines (described below) with the appropriate compiler, you should be able to link the resulting libraries using any of these native compilers (eg., icl, MSVC++). to be linked in using MSVC++, if that is your programming environment of choice. Windows developers using gnu fortran and C as their linkers can just install ATLAS as normal with no special options. Users wanting to link to their ATLAS libs with Windows-style compilers such as MSVC++, CVF, or the Intel compilers should scope the errata entry: http://math-atlas.sourceforge.net/errata.html#WinBuild for full details on how to tell configure what compilers you are interested in.