* Key technology: Vacuum tubes
* Size: Room-sized
* Processing speed: Few thousand operations per second
* Storage: Magnetic drums, punch cards
* Input/output: Teletype machines, punch card readers
* Examples: ENIAC, UNIVAC I
2nd Generation (1950s-1960s): Transistor Based
* Key technology: Transistors
* Size: Smaller; could fit in a standard cabinet
* Processing speed: Tens of thousands of operations per second
* Storage: Magnetic core memory, magnetic tapes
* Input/output: Teletype machines, card readers, printers
* Examples: IBM 1401, PDP-1
3rd Generation (1960s-1970s): Integrated Circuit Based
* Key technology: Integrated circuits (ICs)
* Size: Even smaller; could fit on a desktop
* Processing speed: Millions of operations per second
* Storage: Magnetic disks, floppy disks
* Input/output: Keyboards, monitors, mice
* Examples: IBM 360, DEC PDP-8
4th Generation (1970s-1980s): Microprocessor Based
* Key technology: Microprocessors
* Size: Personal-sized; could be carried around
* Processing speed: Tens of millions of operations per second
* Storage: Hard disks, floppy disks, optical media
* Input/output: Keyboards, monitors, mice, graphics adapters
* Examples: Apple II, IBM PC
5th Generation (1980s-present): Advanced Microprocessor and AI Based
* Key technology: Advanced microprocessors, artificial intelligence (AI)
* Size: Even smaller; could be held in the palm of the hand
* Processing speed: Billions of operations per second
* Storage: Solid-state drives, cloud storage
* Input/output: Touchscreens, voice recognition, gesture control
* Examples: Smartphones, tablets, laptops