It is estimated that there are 10,000 mainframes (computer dinosurs) that run many, many large scale applications in some of the top fortune 500 companies, banks and insurance companies in the world even today. Something that started may be 5 or 6 decades ago - it is still in existence and IBM is still the name to reckon with - in the world of mainframes. Hitachi, Fujitsu, Unisys - were some of the names that resonate with the word - mainframes. From Vaccum tubes, magnetic core memory, magnetic drum storage, tape drives and punched cards to today's mega machines - that can house upto 240 server-grade CPUs, 40TB RAM and Petabytes of flash storage - several decades of travel has been nothing short of a magical journey. From batch mode applications written in Cobol/PL 1 and ran through several JCLs (think Shell programs) - mainframes served the needs of many large scale applications. Late 80s/early 90s saw CICS/DB2 - a major revolution from traditionally batch mode applications backed...