2nd & 3rd - GENERATION COMPUTER (1955 - 1965 - 1974)

Second Generation: Transistors and Batch System (1955 - 1965)           Second generation computers used transistors as CPU components and ferrite cores for main memory and magnetic disk drum/tapes as secondary memory. Some  high  level  languages  introduced  in  this  generation  are  FORTRAN,  ALGOL, BASIC and COBOL. Transistors increased the processing power of computer and decreased the size, cost and power usage as well. Thus, vacuum tubes computers were obsolete. Some  of  the  computers  in  this  generation  are  TX-0  (Transistorized  experimental Computer),  TX-2,  NEAC   1101  (from  NEC),  PDP   series  computers  from  Digital Company, IBM series computers such as IBM 709, IBM 1400 series etc               CDC (Control  Data  Corporation)  built fast computers called supercomputers  -  CDC 6600.  Third Generation: Integrated Circuits and Multiprogramming (1965 - 1980) The invention of silicon ICs (Integrated Circuits) allowed dozens of transistors to be put on a single chip. They used magnetic disks as memory devices but later they were replaced by semiconductor memories. Some of the major achievements are:

Multiprogramming was introduced. The computers were more powerful and smaller than previous generations. OSes like UNIX OS, system /360 OS, IBM MVS, BSD was developed. Some of the programming languages built in this generation are: ada, PASCAL, BCPL, SHRDLU, FORTRAN 66 and 77, SEQUEL (nowadays SQL) Intel introduced its microprocessors - Intel 4004, Intel 8080, 8086, 8088. Examples  of  third  generation  of  computer are  Apple  computers,  CDC's  Cyber-  175 and PDC series, STAR 1100 etc.