# Advances in Emerging Memory Technologies: From Data Storage to Artificial Intelligence
## 2 Market and Trends of Memory Technologies
### General Context and Evolution of Nonvolatile Memories  
#### 2.2.1 The Era of Big Data  
We are living during the big data revolution. Big data mainly affects large companies, in particular the GAFAMI (Amazon, Apple, Facebook, Google, Microsoft, and IBM), but also changes our everyday life. Big data relies on the three Vs: volume, variety, and velocity:  
* First, there is a tremendous volume of generated data. More than two trillion gigabytes (10\({}^{9}\) bytes) are created each day. Moreover, the evolution of data generation follows an exponential growth, and extrapolations forecast 175 ZB of data in 2025 [1], four times more than what we use today. People are forecasted to carry more than four mobile devices and 75% of the worldwide population will be connected to the network [23].  
This data deluge is accompanied by a constant improvement in memory technologies, with bit density and memory capacity increasing by a factor of 1.4 every year [19]. In 2020, a 1-mm\({}^{2}\) die can integrate 10 Gb of memory capacity [19].  
Another important point to mention is that this data increase will be supported by all memory types: even if SSD has the highest increase, HDD and even the tape market will also grow [24]. The IDC (International Data Corporation, global provider of intelligence, advisory services, and events for the information technology, telecommunications, and consumer technology markets) forecasts that over 22 ZB of storage capacity must ship across all media types from 2018 to 2025 to keep up with storage demands.  
* Apart from the high volume of data, there is also a large variety of data in various forms. It differs from application to application. Data come from photos, videos, audio recordings, email messages, documents, books, presentations, tweets, etc., and are generally unstructured.
* Finally, new data are coming quickly. The data flow is the velocity vector. Every day 900 million photos are uploaded to Facebook, 500 million tweets are posted on Twitter, 0.4 million hours of video are uploaded to YouTube, and 3.5 billion searches are performed in Google [25]. On a large scale and considering all the contributions, data traffic was expected to grow by a factor of 1455 from 2018 to 2020, following an exponential evolution, as reported by IBS [26]. In particular, video is expected to maintain a growth rate of 70-80% every year for the next decade [26].  
According to CISCO, data traffic is forecast to increase 2.5 times over the period 2016 to 2021 [27]. The majority of the increase in data traffic is due to the increase in video content delivery, projected to account for 82% of traffic by 2021 [27]. The devices that will thus be the major contributors are smartphones and TVs with respective data traffic percentages of 33% and 30% [28].  
We are also in the era of IoT, with the exponential growth of connected objects in our everyday life. We have smartphones, smart watches, smart clothes, etc. The number of network-connected devices is increasing, from an estimated 18 billion in 2020 to 46 billion in 2030, which represents an almost 300% increase in that period, with an average compound annual growth rate (CAGR) of 9.8% [28]. The majority of this growth is related to automation network connected devices and, in particular, to IoT, which will represent about half of connected device stocks in 2030 [28].