ATARI
1976, Warner Communications buys Atari from Nolan Bushnell for $28 million. In december 1978, Atari announces the Atari 400 and 800 personal computers, using the 6502 microprocessor.  In october 1979, Atari begins shipping the Atari 400 and Atari 800 personal computers. In december of the same year, Sears begins selling Atari home computers. These computers used cartridges for software media and also had a cassette program recorder to save the program you created using the basic computing language cartridge. In may 1981, Atari announces the 8KB Atari 400 is being discontinued.
ATARI 800
The Atari 800 was code-named "Colleen"
The 800 sells for US$1000. 
  • SN; AW305172
With cartridge door open

The back of the 800

Click here to view the Atari 800 mother board
Atari 800 XL
Oct. 1983, Atari begins shipping its 800 XL computer. 
1983  Decline of video games and irresponsible spending by Atari Inc. results in record losses ($536 million, up to $2 million daily). 
In 1983 Atari replaced the 1200XL/800/400 line-up with the new 800XL and 600XL.  These new machines include most of the features of the 1200XL minus the Function keys and the demo program. 
But now both the 800XL and 600XL have the Atari BASIC language built-in.  In addition, these two systems offer the Parallel Bus Interface (PBI), providing direct memory access to the heart of the computer. 
The 800XL contains 64K RAM while the 600XL has 16K RAM. 
  • SN; 288713
  • 64 K Ram

The back of the 800XL
<-Atari cartridge
<-Atari cassette model; 410, sn; TI3075
Please click here for a short history of Atari.

pcbiography.net