Atari 400

Atari 400
An atari 400
Manufacturer:	Atari
Year Introduced:	November 1979
Form Factor:	Microcomputer
Clock Speed:	1.79 MHz
Memory Size:	8 KB - 48KB
CPU:	MOS 6502B
Operating System:	In-ROM Atari BASIC

The Atari 400 was the little brother of the Atari 800. Made by Atari, the 400 was noted for having a membrane keyboard, and a single ROM cartridge slot to keep costs down. The Atari 400 & 800 both initally shipped with 8KB of RAM, however, as RAM prices dropped Atari started to ship machines with more memory. It's worth noting that unlike Commodore's Vic20, the Atari 400 could have its RAM upgraded.

Similar to the Amiga, the Atari 400 had 3 coprocessors, the ANTIC, CTIA/GTIA, and POKEY. And just like the Amiga they were designed by Jay Miner.

From an Atari advertisement, 1982:
THE ATARI 400 HOME COMPUTER
FEATURES AND TECHNICAL
SPECIFICATIONS

Console: FCC approved with built-in RF modulator. Connects to 
  any TV (USA)
CPU: 6502B Microprosessor: 0.56 microsecond cycle. 1.8MHz
Color: 16 colors: each with 8 intensities.
Sound: Four independent sound synthesizers for musical tones 
  or game sounds. 3-1/2 octaves. Variable volume and tone. 
  Internal speaker (in addition to audio through TV).
Memory: Includes 16K bytes of Random Access Memory (RAM) 
  and 10K Read Only Memory (ROM) Operating System. 
  ROM may be expanded with a user-installed cartridge program.
Keyboard: 57-key monopanel alphanumeric keyboard plus 4 special 
  function keys. Upper/lower case. Inverse video. Full screen 
  editing. Four-way cursor control. 29 graphic keys.
I/O: Serial input/output port for simple connection to peripherals. 
  Four controller jacks.
Display: Highest graphics resolution 320 x 192, 24 lines 
  of 40 characters. 3 text modes, 8 graphic modes.
Power: AC transformer, UL approved, included. 120 VAC.
Dimensions: 13 1/2" x 11 1/8" x 4 1/2", 5 3/4 lbs.
Warranty: 90 days parts and labor.
Service: Available at authorized ATARI Factory Authorized 
  Computer Service centers.

Emulators

The Atari800 emulator is portable and somewhat popular. http://atari800.sourceforge.net/