Atari 400/800 Series
8-bit Home Computers

The first Atari Home Computers were shown to the public during the Winter Consumer Electronics Show (CES) in early January, 1979.  The first official small shipment of the Atari 400 and Atari 800 was on August 29th 1979.   These were hand built pilot run units to Sears that needed to be in stock by Sept. 1 so they could be placed in the big fall catalog. The units were placed in the Sears warehouse and then immediately returned to Atari after the "in stock" requirement had been meet.

Atari 800 Computer with Atari 810 Disk Drive

The first "real" consumer units were shipped in November of 1979 and were 400's to Sears followed very shortly by 800's.

These MOS Technology 6502-based systems run at a clock speed of 1.79 MHz, offering 128 colors displayable simultaneously, up to 320x192 graphics resolution and up to 40x24 text resolution in 8 graphics modes and 6 text modes. Video may be displayed either on a composite video monitor in the case of the 800, or on a standard television for both systems. 4 independent sound voices are available through the audio output of the television or monitor, each with a 3 1/2 octave range, plus there is a built-in speaker for key-click and other programmable sounds.

The 800 has a second cartridge port and a full-stroke keyboard, while the 400 has a single cartridge port and a membrane keyboard. Each has 4 serial controller ports and an Atari Serial Input/Output port. Originally, both the 400 and 800 were sold with 8K RAM, but later most 800's were sold with 48K and 400's with 16K. Each includes the 10K Atari Operating System in ROM.

Atari 400 Computer

The 800 can be fitted with 1-3 of the following two RAM modules: CX852 8K RAM module, CX853 16K RAM module and must be fitted with a ROM module: CX801 10K ROM, CX801-P 10K ROM for PAL machines.

In November of 1981, the 400/800 systems were shipping with the new GTIA chip in place of CTIA, increasing the palette of simultaneously displayable colors to 256 and adding 3 new graphics modes. CTIA is totally phased out by the end of the year.  The very first prototype systems did have the GTIA, but it had some problems and was not released in the consumer version until 1981. The GTIA was completed before the CTIA.