History of Computing

First Generation (Mechanical/Electromechanical)
a) Calculators
> Abacus, Antikythera mechanism, Difference Engine, Norden bombsight

b) Programmable Devices
> Jacquard's loom, Analytical Engine, , Digi-Comp I, Digi-Comp II, Geniac, Harvard Mark I

Second Generation (Vacuum Tubes)
a) Calculators
> Atanasoff-Berry Computer
b) Programmable Devices
> ENIAC, EDSAC, EDVAC, UNIVAC I

Third Generation (Discrete transistors and SSI, MSI, LSI Integrated circuits)
a) Mainframes
> System/360, BUNCH
b) Minicomputer
> PDP-8, PDP-11, System/32, System/36

Fourth Generation (VLSI integrated circuits)
a) Minicomputer
> VAX, AS/400
b) 4-bit microcomputer
> Intel 4004, Intel 4040
c) 8-bit microcomputer
> Intel 8008, Intel 8080, Motorola 6800, 6502, Zilog Z80
d) 16-bit microcomputer
> 8088, Zilog Z8000, WDC 65816/65802
e) 32-bit microcomputer
> 80386, Pentium, 68000, ARM architecture
f) 64-bit microcomputer
> x86-64, PowerPC, MIPS, SPARC
g) Embedded computer
> 8048, 8051
h) Personal computer
> Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA),
Portable computer, Tablet computer, Wearable computer

Theoretical/experimental
a) Quantum computer
b) Chemical computer
c) DNA computing
d) Optical computer

For more information

http://www.computerhistory.org, http://en.wikipedia.org/wiki/Computer