- 1st Generation iPod- First announced on October 23,2001, the original iPod cost US$399 with a 5 GB hard drive. Critics panned the unit's price, but iPod proved an instant hit in the marketplace, quickly overtaking earlier hard drive MP3 players such as the NOMAD Jukebox. Apple announced a 10 GB version (US$499) in March 2002.
Apple designed a mechanical scroll wheel and outsourced the implementation and development to Synaptics, a firm which also developed the trackpad for Apple's PowerBooks. The 1st generation iPod featured four buttons (Menu, Play/Pause, Back, and Forward) arranged around the circumference of the scroll wheel, and one Select button in the center.
- 2nd Generation iPod-
Introduced on July 17, 2002, at Macworld in 10 GB and 20 GB capacities, the 2nd generation iPod replaced the mechanical scroll wheel of the original with a touch-sensitive, non-mechanical one (also manufactured by Synaptics), termed a "touch wheel." Due to new Toshiba hard drives, the 20 GB iPod slightly exceeded its 1st generation counterpart in thickness and weight, while the 10 GB model was slimmer. The 2nd generation iPod came with a carrying case and wired remote and it was the first generation that was officially compatible with Windows (although it is possible to reformat 1st generation iPods to be Windows-compatible).
- 3rd Generation iPod-
On April 28, 2003, Steve Jobs introduced an "ultrathin" iPod series. Slightly smaller than their predecessors, they had more distinctively beveled edges. Over the life of the 3rd generation iPod series, Apple produced 10 GB, 15 GB, 20 GB, 30 GB, and 40 GB sizes. These iPods use a 30-pin connector called the Dock Connector — longer and flatter than a FireWire connector. The iPod Dock came bundled with all but the least expensive iPod and also retailed separately.
The 3rd generation iPod featured touch-sensitive buttons located between the display and touch wheel. The new buttons featured red backlighting, allowing easier use in darkness.
- 4th Generation iPod-
In July 2004, Apple released the 4th generation iPod. In a new publicity route, Steve Jobs announced it by becoming the subject of a Newsweek magazine cover. The 4th generation iPod is considered the model in which sales greatly increased, thus starting the "iPod Craze."
In the most obvious difference from its predecessors, the 4th generation iPod carries over the click wheel design introduced on the iPod mini. Like its predecessors, the 4th generation iPod originally had a monochrome screen and no photo capabilities. It came in one of two sizes: 20 GB for US$299 and 40 GB for US$399. In February 2005 Apple discontinued the 40 GB model and began solely selling a monochrome 20 GB version.
- iPod photo-
Released on October 28, 2004, iPod photo (originally named iPod Photo — with a capital P — but renamed less than a month after its launch) featured a 220x176 pixel (maximum pixel count of 38,720), 16-bit color screen capable of displaying 65,536 colors, and the ability to store and display JPEG, BMP, GIF, TIFF, and PNG images. One millimeter thicker than the standard monochrome 4th generation iPod, iPod photo could also play music for up to 15 hours per battery charge. It originally came in 40 GB and 60 GB versions, which cost US$499 and US$599, respectively.
- 5th Generation iPod-
On October 12, 2005 Apple launched the 5th generation iPod at the "One more thing..." event. This iPod is often called the iPod video or the video iPod, while Apple documentation refers to it as the Fifth Generation iPod or iPod with video.
5th generation iPods are available in 30 GB and 60 GB capacity models and are priced the same as the previous generation at US$299 and US$399, respectively. They also feature the ability to play MPEG-4 and H.264 video with resolutions of up to 480x480 (maximum macroblock (16x16 pixel) count of 900) and 320x240 (maximum macroblock (16x16 pixel) count of 300), respectively (videos purchased from the iTunes Music Store are limited to 320x240). Some users have reported the ability to play widescreen resolutions up to 640x360 using MPEG-4 and 400x192 using H.264 (total macroblock count falls within the stated maximums).
The dimensions are 4.1 x 2.4 x 0.43 inches for the 30 GB version, and 4.1 x 2.4 x 0.55 inches for the 60 GB version. The screen size is now 2.5 inches (6.35 cm) diagonally, 0.5 inches (12.7 mm) larger than the previous iPod. It is also 30% thinner than the previous full-size iPod. The reported battery life for the 30 GB is 14 hours and for the 60 GB is around 20 hours. Watching movies reduces that amount to 2 and 3 hours respectively.
- 1st Generation iPod mini-
On January 6, 2004, Apple introduced the first iPod mini. It had 4 GB of storage and a price of US$249 (at the time, only US$50 below the 15 GB 3rd generation iPod). Critics panned it as too expensive, but it proved to be overwhelmingly popular, and Apple Stores had difficulty keeping the model in stock.
The iPod mini introduced the popular "click wheel" that was incorporated into later iPods: the touch-sensitive wheel means that users can move a finger around it to highlight selections on the screen, while the unit's Menu, Back, Forward, and Play/Pause buttons are part of the wheel itself, letting a user press down on part of the wheel to activate one of those functions. The center button still acted as a select button. Apple initially made iPod mini devices available in five colors: silver, gold, blue, pink, and green. Silver models sold best, followed by blue ones, while the least popular model was gold.
- 2nd Generation iPod mini-
In February 2005, the 2nd generation iPod mini came on the market with a new 6 GB model at US$249 and an updated 4 GB model priced at US$199. Most notably, both models featured an increased battery life of up to 18 hours. In addition, they featured richer case colors (though Apple discontinued the gold color) and other minor aesthetic changes (the color of the lettering on the click wheel now matched the color of the iPod mini). Also, the 2nd generation minis did not include the AC adapter or the FireWire cable bundled with previous models. It instead came bundled with a USB 2.0 to Dock Connector cable.
- iPod Shuffle-
Apple announced iPod shuffle at Macworld Expo on January 11, 2005 with the taglines "Life is random" and "Give chance a chance." iPod shuffle introduced flash memory (rather than a hard drive) to iPods for the first time. The shuffle comes in two models: 512 MB (up to 120 four-minute songs encoded at 128 kbit/s) and 1 GB (up to 240).
The iPod shuffle has no screen and thereforee has limited options for navigating between music tracks: users can play songs either in the order set in iTunes or in a random (shuffled) order. Users can set iTunes to fill iPod shuffle with a random selection from their music library each time the device connects to the computer. The iPod shuffle weighs less than one ounce (0.78 oz. or 22 g), the lightest iPod to date, and approximates in size to a pack of chewing gum.
- iPod nano-
On September 7, 2005, Apple announced iPod nano, the successor to the iPod mini. Based on flash memory instead of a hard drive, the iPod nano is 0.27 inches (6.9 mm) thick, weighs 1.5 ounces (42 g), and is 62% smaller by volume than its predecessor. Available in both black and white and 1 GB (introduced on 7 February 2006, at US$149), 2 GB (US$199), and 4 GB (US$249) capacities for a total of six models. It has a 65,536 color screen that can display photographs. It connects to a computer via USB 2.0, and the headphone jack is located at the bottom. It retains the standard 30-pin dock connector for compatibility with third-party peripherals.