and do not have moving parts they require less battery power, will not skip during playback, and may be more resilient to hazards such as mechanical shock or fragmentation than hard disk-based players. Hard drive-based players: Devices that read digital audio files from a hard disk drive. These players have higher capacities ranging up to 500 GB. At typical encoding rates, this means that tens of thousands of songs can be stored on one player. The disadvantages with these units is that a hard drive consumes more power, is larger and heavier and is inherently more fragile than solid-state storage. MP3 CD/DVD players: Portable CD players that can decode and play MP3 audio files stored on CDs. Such players were typically a less expensive alternative than either the hard drive or flash-based players when the first units of these were released. The blank CD-R media they use is inexpensive. These devices have the feature of being able to play standard audio CDs. A disadvantage is that due to the low rotational disk speed of these devices, they are even more susceptible to skipping or other misreads if they are subjected to acceleration (shaking) during playback. Since a CD can typically hold only around 700 megabytes of data, a large library will require multiple disks to contain. However, some higher-end units are also capable of reading and playing back files stored on larger-capacity DVD; some also have the ability to play video content, such as movies. An additional consideration can be the relatively large width of these devices since they have to be able to fit a CD. Networked audio players: Players that connect via (WiFi) network to receive and play audio. These types of units typically do not have any local storage of their own and must rely on a server, typically a personal computer also on the same network, to provide the audio files for playback. History Today, every smartphone also serves as a portable media player; however, prior to the rise of smartphones in the 2007-2012 time frame, a variety of handheld players were available to store and play music. The immediate predecessor in the market place of the digital audio player was the portable CD player and prior to that, the personal stereo. In particular, Sony's Walkman and Discman are the ancestors of digital audio players such as Apple's iPod. There are several types of MP3 players: