The OSPOS project was written in C++, with X Window System based GUI, MySQL datebase, CUPS printers support, UnifiedPOS compatible, currectly developing on Linux, and will run on all POSIX-oriented operating systems, faster, simpler, maybe better : )
Not the most complex, but very functional
How could I solve the "Unable to load the requested language file: language/English/common_lang.php" message?
Did you know that a project by this name already exists? You might consider changing the name of your project: /projects/opensourcepos/