Question: How many iterations of the DS have been released?

Nintendo DS family


The Nintendo DS family is a family of handheld game consoles that were developed and sold by Nintendo.
Initially released as an experimental platform ancillary to the then-current Game Boy Advance family, Nintendo DS soon replaced it as Nintendo's flagship handheld device family. The DS was distinguished by its predecessor by featuring a folding "clamshell" form factor and two screens—the lower screen being a touchscreen enabling input with an included stylus pen. It was also Nintendo's first handheld console to have built-in wireless capabilities, supporting both local communication between other DS consoles, and internet communications via the now-discontinued Nintendo Wi-Fi Connection service. 
The line comprised three models; the original Nintendo DS, the Nintendo DS Lite—a streamlined version of the original model with brighter screens, and the Nintendo DSi—an enhanced iteration of the DS Lite with updated hardware, support for internal and removable storage, cameras, and updated system software with photo and sound recording apps, as well as the ability to download and purchase additional software via the DSIWare store. The DSi was also released in a larger XL model.
Throughout its lifetime, Sony's PlayStation Portable has been the main market competitor. There have been four different models of the Nintendo DS line on the market: the original Nintendo DS, the Nintendo DS Lite, as well as the Nintendo DSi and its XL variant. The Nintendo DS line has been highly successful, continuing the trend of its predecessor, the Game Boy line. With over 154 million units sold worldwide, the DS models are the best-selling handheld consoles, and second best-selling console overall behind the PlayStation 2. 
The DS line was officially superseded by the Nintendo 3DS family in 2011; the 3DS line carries similarities in functionality to the DSi, but with further enhancements to its internal hardware and software, as well as some models featuring an autostereoscopic 3D display.
History


Timeline

Nintendo DS family
Nintendo DS



The Nintendo DS (abbreviated to DS)  is a dual-screen handheld game console developed and released by Nintendo. The device went on sale in North America on November 21, 2004. The DS, short for "Developers' System" or "Dual Screen",[1] introduced distinctive new features to handheld gaming: an LCD screen working in tandem with a touchscreen, a built-in microphone, and support for wireless connectivity.[2] Both screens are encompassed within a clamshell design similar to the Game Boy Advance SP. The Nintendo DS also features the ability for multiple DS consoles to directly interact with each other over Wi-Fi within a short range without the need to connect to an existing wireless network.  Alternatively, they could interact online using the now-discontinued Nintendo Wi-Fi Connection service.

Prior to its release, the Nintendo DS was marketed as a "third pillar" in Nintendo's console lineup, meant to complement the Game Boy Advance and GameCube. However, backward compatibility with Game Boy Advance titles and strong sales ultimately established the new handheld console as the successor to the Game Boy series.
Nintendo DS Lite



The Nintendo DS Lite (abbreviated to DS Lite) is a dual-screen handheld game console developed and manufactured by Nintendo. It is a slimmer, brighter, and more lightweight redesign of the original Nintendo DS. It was announced on January 26, 2006, more than a month before its initial release in Japan on March 2, 2006 due to overwhelming demand for the original model. [3] It has been released in Australia, North America, Europe, New Zealand, Singapore, and defined regions in South America, the Middle East, and East Asia. As of December 31, 2013, shipments of the DS Lite have reached 93.86 million units worldwide, according to Nintendo. It was the final handheld to have backwards compatibility with Game Boy Advance games.[4]
Nintendo DSi


The Nintendo DSi (abbreviated to DSi)[5] is a dual-screen handheld game console released by Nintendo. The console launched in Japan on November 1, 2008, and worldwide beginning in April 2009. It is the third iteration of the Nintendo DS, and its primary market rival is Sony's PlayStation Portable (PSP). Development of the DSi began in late 2006, and the handheld was unveiled during an October 2008 Nintendo conference in Tokyo. Consumer demand convinced Nintendo to produce a slimmer handheld with larger screens than the DS Lite. Consequently, Nintendo removed the Game Boy Advance (GBA) cartridge slot to improve portability without sacrificing durability.
While the DSi's design is similar to that of the DS Lite, it features two digital cameras, supports internal and external content storage, and connects to an online store called the Nintendo DSi Shop (which was discontinued in 2017) . Nintendo stated that families often share DS and DS Lite consoles. Its new functionality was intended to facilitate personalization, so as to encourage each member of a household to purchase a DSi. The handheld supports exclusive physical media in addition to DS games with DSi-specific features and standard DS titles. The only exception to its backward compatibility are earlier DS games that required the GBA slot. As of September 30, 2014, Nintendo had sold 41.37 million DSi and DSi XL units combined.[4]

Reviews of the Nintendo DSi were generally positive; although IGN and bit-tech decried the console's lack of exclusive software and removal of the GBA cartridge slot, its added functionality caused many journalists to recommend it to those who had not purchased a previous DS model. Numerous critics were disappointed with the limited resolution of DSi's cameras, though others such as Ars Technica and GameSpot agreed they were adequate for the handheld's display. CNET and PCWorld considered the DSi Shop to be the most important buying incentive for current DS owners.
Nintendo DSi XL


The Nintendo DSi XL (abbreviated to DSi XL) features larger screens, and a greater overall size, than the original DSi. It is the fourth DS model, the first to be available as a pure size variation.[6] Iwata said that cost restraints had, until then, limited the screen size and multiplayer aspects of portable game consoles, and that the DSi XL offers "an improved view angle on the screens", which makes it the first "portable system that can be enjoyed with people surrounding the gamer."[6] He argued that this introduces a new method of playing portable video games, wherein those "surrounding the game player can also join in one way or the other to the gameplay."[6] While the original DSi was specifically designed for individual use, Iwata suggested that DSi XL buyers give the console a "steady place on a table in the living room," so that it might be shared by multiple household members.[6]

The DSi XL is the longest, widest and heaviest DS model.[5][7] The console features two 4.2-inch (110mm) wide-viewing-angle LCD screens with the same resolution as the smaller model.[8] It has improved battery life over the DSi on all brightness settings; for example, batteries last 13–17 hours at the dimmest setting.[5] The handheld is outfitted with identical speakers contained in larger speaker enclosures, enabling them to produce louder sound. The hinges stop the screen at 120° in addition to the original DSi's position of 155° to allow easier table-top viewing.[9] The DSi XL is bundled with two longer styli, one of which is thicker, rounded, and pen-like,[10] and does not fit inside the unit.[11]
Comparison


Accessories

Nintendo big stylus was made for the Nintendo DSi XL
See also
Nintendo 3DS family
Game Boy line