Enabled a hierarchical view of molecules, residues and atoms (available from 'Selection' tab). Added different manipulation modes (all, molecules, fragments). Added atom labeling feature. Added suport for. The 'classic' Mac OS is the original Macintosh operating system that was introduced in 1984 alongside the first Macintosh and remained in primary use on Macs until the introduction of Mac OS X in 2001. Apple released the original Macintosh on January 24, 1984; its early system software was partially based on the Lisa OS and the Xerox PARC Alto computer, which former Apple CEO Steve Jobs. Cross-Platform: Molecular builder/editor for Windows, Linux, and Mac OS X. Free, Open Source: Easy to install and all source code and documentation is available to modify or extend.; International: Translations into Chinese, French, German, Italian, Russian, Spanish, and others, with more languages to come.; Intuitive: Built to work easily for students and advanced researchers both. Research at the Frontiers of Biophysics. Chemblr20150.mdb is a library of lightweight fragments (molecular weight Mac: $ gzip -d chemblr20frags.mdb.gz or $ gzip -d chemblr20150.mdb.gz.