He really invented a lot of good mainframe technology. Worked at IBM and then left to make his own company to compete with IBM making IBM Mainframe clones that ran faster and cost less than an IBM Mainframe.<p>I grew up in the era that used IBM 360&#x2F;370 mainframes and I learned them in college for FORTRAN and COBOL and JCL with DOS&#x2F;VSE. I don&#x27;t think colleges teach mainframe technology anymore now that PCs have taken over.<p>Things moved from PCs to mobile devices so quick as well.<p>Edit;Typo