This Historical Survey Of Parallel Processing From 1980 To 2020 Is A Follow-up To The Authors' 1981 Tutorial On Parallel Processing, Which Covered The State Of The Art In Hardware, Programming Languages, And Applications. Here, We Cover The Evolution Of The Field Since 1980 In: Parallel Computers, Ranging From The Cyber 205 To Clusters Now Approaching An Exaflop, To Multicore Microprocessors, And Graphic Processing Units (gpus) In Commodity Personal Devices; Parallel Programming Notations Such As Openmp, Mpi Message Passing, And Cuda Streaming Notation; And Seven Parallel Applications, Such As Finite Element Analysis And Computer Vision. Some Things That Looked Like They Would Be Major Trends In 1981, Such As Big Single Instruction Multiple Data Arrays Disappeared For Some Time But Have Been Revived Recently In Deep Neural Network Processors.