The document discusses the development of next generation sequencing (NGS) technology. It describes how the first NGS platform was developed and released in 2005, sparking many applications due to reduced costs and increased sequencing data output. It also covers the working mechanisms of Illumina and Ion Torrent sequencing, comparing NGS instruments at the levels of read alignments, statistical analysis, and biological inferences. Advantages and disadvantages of NGS are mentioned as well.