Atari's entry in the home console industry, and one that innovated across the board, despite the fact that the 2600 was not really the “first” in anything. Releasing in September 1977 in the USA, the 2600 was quite capable for the time, although this pales in comparison to the power consoles held even a few years later. In this power, the 2600 ran off 128 bytes of RAM, a MOS 6507 at 1.19MHz, and could display 16 possible colors with 8 levels of brightness within each color, or 128 different shades. Selling 30 million units over the decades, the 2600 was a smash hit for the newly conceived “home video game” console market.

https://en.wikipedia.org/wiki/Atari_2600

I'm moving the cursor around, and the Pong game is playable

Appears to be the first of it’s kind in the name of psuedo-OSes for the Atari 2600. Has a few cool features, while also receiving forum attention for quite a while.

https://www.youtube.com/watch?v=R_EkNo02wa8

https://atariage.com/forums/topic/91546-atari-2600-gui/

https://atariage.com/forums/topic/91546-atari-2600-gui/page/5/ (newest version 11/20/06)

So basically it fires up to a 'desktop' screen with a folder, trash can and a clock.

Essentially the same thing as the “Atari OS” immediately below this listing, except somebody else made it instead.

https://atariage.com/forums/topic/262668-atari-2600-os-homebrew/

https://atariage.com/forums/applications/core/interface/file/attachment.php?id=494191

a GUI of sorts for the atari 2600 using batari basic

Yet another simple “OS” for the Atari 2600, this time using Batari BASIC. Quite like the other ones, this can't do much, but it has a few simplistic features like program windows.

https://atariage.com/forums/topic/90210-atari-os-finished/page/4/#comments

https://atariage.com/forums/applications/core/interface/file/attachment.php?id=58132

I have added a simple Pong game to the OS

Another simple psuedo-OS for the Atari 2600, which received a few updates. Features a few tiny programs, quite like the other ones above.

https://atariage.com/forums/topic/295944-atari-tos-2600-wip/

the ability to download and start cartridge images over the internet.

Similar to the Gameline service that was active at the time, but more “open” for the obvious reasons of being a homebrew project.. Creator mentioned making a web browser, but lost interest (🤷‍♂️) before anything happened.

https://atariage.com/forums/topic/247229-atari-2600-cartridge-with-wifi/

Since the old Atari 2600 video game system designed in 1977 also runs on a 6502 variety CPU (the 6507), I was curious if I could create a little Java API

Mike Kohn's Java Grinder has made it so you can now run Java programs on the Atari 2600. Amazing! Of course, these programs must be written specifically for the 2600 due to it's very low specification.

https://www.mikekohn.net/micro/atari2600_java.php

For general information, see the Game Console Revisions Overview.

This guide has been essentially depreciated by the excellent work of our friends over at consolemods.org. It is linked below.

https://consolemods.org/wiki/Atari_2600:Atari_2600_Model_Differences

There are three versions of this console, arranged chronologically.

RECOMMENDED OVERALL

Both difficulty switches, which are known to alter the way games perform, are placed on the front panel for easy access. May have stronger color saturation.

The aforementioned difficulty switches above have now been moved to the console's behind, hidden from view.

Functionality is the same as the Four Switch, but the design has been significant overhauled to be smaller, thinner, and with a distinctive silver/rainbow part in the middle (usually). May have poorer reliability. One all-black variant exists, but it’s changes are entirely cosmetic, and it was only sold in Ireland.

There are two revisions within the 2600 (Six Switch; Woody) and 2600 (Four Switch), and no revisions within the 2600 Jr.

BEST RELIABILITY

These are the first released models of the Atari 2600. While not confirmed, it is often postulated that these are the best of even the Six Switchers, as they were all produced in Sunnyvale, California, rather than an overseas location. Common claims are that they have the best color output and saturation. However, rarity/price is a downside, due to the limited run these consoles had.

RECOMMENDED OVERALL

These are the vast majority of Six Switch Atari 2600s. In essence, the only difference between this revision and the prior one, is console weight + plastic molding + production location. They will be found much more easily than the “Heavy Sixer”, while offering zero feature sacrifice and minor reliability sacrifice.

The only apparent difference between this and the “Light Sixer” is the relocation of the switches. Appears very common, possibly the most common? With my basic searching, I am willing to say that yes, this is the most common variant. However, this is still inconclusive, so a “LOWEST PRICE” assignment is not warranted.

Commonly known as the “Darth Vader”, due to it’s sleeker all black appearance and no woodgrain. Outside of this visual difference, the console’s only technical change is the pre-existing difficulty switch relocation. There may be minor motherboard revisions for both of these, but the maximum extent for latest models is the addition of a timer chip, which eliminates the minor issue of reset failures upon powering on the console.

https://en.wikipedia.org/wiki/Atari_2600_hardware

https://www.youtube.com/watch?v=eZ0ISXgWREo (1988/1989 phaseout date source)

https://www.atariage.com/2600/archives/consoles.html

http://www.retrogamescollector.com/spotters-guide-to-the-atari-2600-vcs-woody-junior/