There are many advantages for Mainframe than the today's technologies like. 1  Reliable. 2  Servicability. 3  Security. 4  Availabilty (99.99% up time). 5  Scalabilty.6  It is compatible with C/C++, COBOL, JAVA/J2EE, Assembler, REXX, Shell script, Fortran and languages from 1960 to now.calability-the power of IBM's Z System processor can move mountains of data, billions of instructions and supports parallel processing. A batch job that copies billions of records from one file to another file structure can take minutes instead of hours.