data science in big data world the previous description of the data science process gives you the impression that you walk through this process in linear waybut in reality you often have to step back and rework certain findings for instanceyou might find outliers in the data exploration phase that point to data import errors as part of the data science process you gain incremental insightswhich may lead to new questions to prevent reworkmake sure that you scope the business question clearly and thoroughly at the start an iterative process now that we have better understanding of the processlet' look at the technologies the big data ecosystem and data science currently many big data tools and frameworks existand it' easy to get lost because new technologies appear rapidly it' much easier once you realize that the big data ecosystem can be grouped into technologies that have similar goals and functionalitieswhich we'll discuss in this section data scientists use many different technologiesbut not all of themwe'll dedicate separate to the most important data science technology classes the mind map in figure shows the components of the big data ecosystem and where the different technologies belong let' look at the different groups of tools in this diagram and see what each does we'll start with distributed file systems distributed file systems distributed file system is similar to normal file systemexcept that it runs on multiple servers at once because it' file systemyou can do almost all the same things you' do on normal file system actions such as storingreadingand deleting files and adding security to files are at the core of every file systemincluding the distributed one distributed file systems have significant advantagesthey can store files larger than any one computer disk files get automatically replicated across multiple servers for redundancy or parallel operations while hiding the complexity of doing so from the user the system scales easilyyou're no longer bound by the memory or storage restrictions of single server in the pastscale was increased by moving everything to server with more memorystorageand better cpu (vertical scalingnowadays you can add another small server (horizontal scalingthis principle makes the scaling potential virtually limitless the best-known distributed file system at this moment is the hadoop file system (hdfsit is an open source implementation of the google file system in this book we focus on the hadoop file system because it is the most common one in use howevermany other distributed file systems existred hat cluster file systemceph file systemand tachyon file systemto name but three