Editing Intellivision (section)

===Software===
Inside every Intellivision console is 4K of [[Read-only memory|ROM]] containing the Exec software. It provides two benefits: reusable code that can effectively make a 4K cartridge an 8K game and a [[software framework]] for new programmers to develop games more easily and quickly. It also allows other programmers to more easily review and continue another's project. Under the supervision of David Rolfe at APh, and with graphics from [[Mattel]] artist Dave James, APh was able to quickly create the Intellivision [[launch game]] library using mostly summer students.<ref name=lives_companies>{{usurped|1=[https://web.archive.org/web/20170614/http://www.intellivisionlives.com/bluesky/people/companies.html Where Are They Now?]}} intellivisionlives.com</ref> The drawback is that to be flexible and handle many different types of games, the Exec runs less efficiently than a dedicated program. Intellivision games that leverage the Exec run at a 20&nbsp;Hz [[frame rate]] instead of the 60&nbsp;Hz frame rate for which the Intellivision was designed. Using the Exec framework is optional, but almost all Intellivision games released by Mattel Electronics use it and thus run at 20&nbsp;Hz. The limited [[ROM cartridge|ROM]] space in the early years of Intellivision game releases also means there is no space for a computer player, so many early multiplayer games require two human players.

Initially, all Intellivision games were programmed by an outside firm, APh Technological Consulting,<ref name="Gamasutra"/> with 19 cartridges produced before Christmas 1980. Once the Intellivision project became successful, software development was brought in-house. Mattel formed its own software development group and began hiring programmers. The original five members of that Intellivision team were Mike Minkoff, Rick Levine, John Sohl, [[Don Daglow]], and manager Gabriel Baum. Levine and Minkoff, a long-time Mattel Toys veteran, both transferred from the hand-held Mattel game engineering team. During 1981, Mattel hired programmers as fast as possible. Early in 1982 Mattel Electronics relocated from Mattel headquarters to an unused industrial building. Offices were renovated as new staff moved in. To keep these programmers from being hired away by rival [[Atari, Inc.|Atari]], their identities and work location was kept a closely guarded secret. In public, the programmers were referred to collectively as the [[Blue Sky Rangers]].

Most of the early games are based on traditional real-world concepts such as sports, with an emphasis on realism and depth of play within the technology of the time. The Intellivision was not marketed as a toy; as such, games such as ''Sea Battle'' and ''B-17 Bomber'' are not made in the pick-up-and-play format like [[arcade game]]s. Reading the instructions is often a prerequisite. Every cartridge produced by Mattel Electronics includes two plastic controller overlays to help navigate the 12-button keypad, although not every game uses it. Game series, or networks, are ''Major League Sports'', ''Action'', ''Strategy'', ''Gaming'', ''Children's Learning'', and later ''Space Action'' and ''Arcade''. The network concept was dropped in 1983, as was the convenient gatefold-style box for storing the cartridge, instructions, and overlays.

Starting in 1981, programmers looking for credit and royalties on sales began leaving both APh and Mattel Electronics to create Intellivision cartridges for third-party publishers. They helped form [[Imagic]] in 1981, and in 1982 others joined [[Activision]] and Atari. Cheshire Engineering was formed by a few senior APh programmers including David Rolfe, author of the Exec, and Tom Loughry, creator of one of the most popular Intellivision games, ''[[Advanced Dungeons & Dragons: Cloudy Mountain|Advanced Dungeons and Dragons]]''.<ref name="loughry">{{cite web |last1=Goninon |first1=Mark |title=Where are they now? – Tom Loughry |url=https://www.choicestgames.com/2014/11/where-are-they-now-tom-loughry.html |website=Choicest Games |access-date=26 Nov 2014 |archive-date=20 August 2016 |archive-url=https://web.archive.org/web/20160820010734/http://www.choicestgames.com/2014/11/where-are-they-now-tom-loughry.html |url-status=live }}</ref> Cheshire created Intellivision games for Activision. Third-party developers Activision, Imagic, and Coleco started producing Intellivision cartridges in 1982, and Atari, [[Parker Brothers]], [[Sega]], and Interphase followed in 1983. The third-party developers, not having legal access to Exec knowledge, often bypassed the Exec framework to create smooth 30&nbsp;Hz and 60&nbsp;Hz Intellivision games such as ''The Dreadnaught Factor''. Cheaper [[Read-only memory|ROM]] prices also allowed for progressively larger games as 8K, 12K, and 16K cartridges became common. The first Mattel Electronics Intellivision game to run at 60&nbsp;Hz was ''Masters of the Universe'' in 1983.<ref>https://www.linkedin.com/in/rick-koenig-71a50412/ {{Dead link|date=January 2022}}</ref> Marketing dubbed the term "Super Graphics" on the game's packaging and marketing.

Mattel Electronics had a competitive advantage in its team of experienced and talented programmers. As competitors often depended on licensing well known [[trademark]]s to sell video games, Mattel focused on original ideas. Don Daglow was a key early programmer at Mattel and became director of Intellivision game development. Daglow created [[Utopia (1981 video game)|''Utopia'']], a precursor to the [[Construction and management simulation|sim genre]] and, with Eddie Dombrower, the ground-breaking sports simulation [[Intellivision World Series Baseball|''World Series Major League Baseball'']]. Daglow was also involved with the popular Intellivision games ''Tron Deadly Discs'' and ''Shark! Shark!''.<ref name="gama_dd_art">{{cite web |last1=Wallis |first1=Alistair |title=Playing Catch Up: Stormfront Studios' Don Daglow |url=https://www.gamasutra.com/view/news/102180/Column_Playing_Catch_Up_Stormfront_Studios_Don_Daglow.php |website=Gamasutra |date=19 October 2006 |access-date=19 Oct 2006 |archive-date=12 May 2012 |archive-url=https://web.archive.org/web/20120512140400/http://www.gamasutra.com/view/news/102180/Column_Playing_Catch_Up_Stormfront_Studios_Don_Daglow.php |url-status=dead }}</ref><ref name="gama_dd_int">{{cite web |last1=Sheffield |first1=Brandon |last2=Frank |first2=Frank |title=From Intellivision To Today: Talking To Don Daglow |url=https://www.gamedeveloper.com/game-platforms/from-intellivision-to-today-talking-to-don-daglow |website=Gamasutra |date=30 January 2009 |access-date=30 Jan 2009 |archive-date=10 May 2012 |archive-url=https://web.archive.org/web/20120510222921/http://www.gamasutra.com/view/news/112971/From_Intellivision_To_Today_Talking_To_Don_Daglow.php |url-status=live }}</ref> After Mattel Electronics closed in 1984, its programmers continued to make significant contributions to the videogame industry. Don Daglow and Eddie Dombrower went on to [[Electronic Arts]] to create ''[[Earl Weaver Baseball]]'', and Don Daglow founded [[Stormfront Studios]]. Bill Fisher, Steve Roney, and Mike Breen founded [[Quicksilver Software]], and David Warhol founded [[Realtime Associates]].<ref name=lives_companies/>