Evolution of design

(modern) mainframe is still a very large machine, sometimes tens of square meters. Has usually more than one processor and loads of memory: often running between a few mega- to several hundreds Gb of RAM.

It has tons of disk space and other storage facilities in large size and quantities that are not normally found with mini or micro computers.

1954: The IBM 704, the first mass-produced computer with 

floating point arithmetic hardware 

1958: IBM 7070 was a decimal architecture intermediate data 

processing system 

 1970: The IBM System/370 (S/370)

1990: ESA/390 (Enterprise Systems Architecture/390) 

2005: IBM System z9 is a line of IBM mainframe. 

                                   2008: The z10 Enterprise Class (EC) IBM

 2008: z10 Business Class (BC) 

2010: The older enterprise-class server the IBM z Enterprise 

                                                                 196 (z196) 

2010: The IBM zEnterprise System (zEnterprise),

2011: The smaller business class server the IBM z

Enterprise 114 (z114) 

2012: The IBM zEnterprise EC12