Hardware / The family tree

The machines.

Seven landmark models across four design generations, from Atari's rugged first home computers to the graphical, MIDI-equipped ST.

1979

Atari 400 / 800

The original pair

The Atari 400 used a wipe-clean membrane keyboard and originally shipped with less memory, while the 800 offered a full-stroke keyboard, two cartridge slots, four joystick ports, and accessible expansion bays. Both shared Atari's custom-chip architecture.

Processor	MOS Technology 6502 at approximately 1.79 MHz (NTSC)
Memory	Configurations varied; later Atari 800 systems commonly reached 48K
Graphics & sound	ANTIC plus CTIA/GTIA graphics; POKEY four-channel sound
Character	Heavy shielding, distinctive industrial design, and exceptional audio-visual capability for the era

1983

Atari 600XL / 800XL

The XL refinement

The compact 600XL and larger 800XL put the same essential architecture into a crisp beige-and-brown enclosure. Built-in BASIC made programming immediate, while the 800XL's 64K gave it the broadest appeal.

Processor	6502C/SALLY, approximately 1.79 MHz (NTSC)
Memory	600XL: 16K; 800XL: 64K
Connectivity	SIO peripheral bus; cartridge; joystick ports; monitor/RF output varies by market and model
Character	The definitive all-in-one Atari eight-bit form for many owners

1985

Atari 65XE / 130XE

Eight-bit, restyled

The XE series adopted a case that visually complemented the new ST. The 65XE largely continued the 800XL formula, while the 130XE added bank-switched memory and the Enhanced Cartridge Interface.

Processor	6502C/SALLY, approximately 1.79 MHz (NTSC)
Memory	65XE: 64K; 130XE: 128K with bank switching
Compatibility	Broadly compatible with the established Atari eight-bit software library
Character	A final polished home-computer form for Atari's long-lived eight-bit design

1985

Atari ST

The sixteen-bit studio

The ST was a clean break: Motorola 68000 power, a graphical desktop, double-sided floppy storage on later models, and built-in MIDI. Its balance of price and capability made it a home, business, gaming, and music-production machine.

Processor	Motorola 68000 at 8 MHz on classic ST models
Memory	Early models began at 512K; the 1040ST made 1MB a defining configuration
Display	Low and medium-resolution color modes; 640×400 high-resolution monochrome
Character	Fast graphical interaction, accessible 68000 development, and built-in MIDI