Every semester, all modules are edited and updated by the SME to keep the information abreast. Every semester also, the Library will receive these new modules for ’safekeeping’.  As a repository centre, the TSDAS Digital Library keeps all printed modules for archival purposes.  Students are allowed to use only the current semester’s modules but not the previous modules. Which means, if the current semester is September 2008, only modules published/produced in September 2008 are allowed to be referred by students.  This also means that previous modules in BM are no longer made available for reference.