Answer:
First generation — 1940–1956
-used vacuum tubes
ENIAC, UNIVAC I, IBM 650, IBM 701 etc.
mainframes taking up entire rooms
punched cards I/O
electrostatic and mercury delay line memory, beginning use of core
Second generation — 1956-1963
-used discrete transistors
IBM 7090 and 7094, UNIVAC 1107, PDP-1 and 8, etc.
first appearance of minicomputer (PDP-8)
punched cards I/O and line printers (mainframe), TTY (minicomputers)
core memory, magnetic tape for mass storage
Third generation — 1964-1971
-used integrated circuits
IBM System/360, UNIVAC 1108, PDP-8/I, PDP-11/20 and PDP-11/45, etc.
mostly same I/O and memory as second generation
Fourth generation — 1971-present
-use microprocessors
PDP-11/03 and PDP-11/34, Apple ][, IBM PC, Apple Macintosh, IBM z Series, etc.
transition from minicomputers to personal computers
video terminals used for I/O, specialty computer printers developed
fewer mainframes
semiconductor memory replaces core memory
hard drives and optical drives replace magnetic tape for mass storage, followed by solid-state drives (SSD)
Fifth generation — (current research)
-artificial intelligence and quantum computing
