crud operations must be performed in securereliableand controlled manner this also helps you set few guidelines for how access must occur to ensure data integrity ( measure of how often data errors occur when performing crud operationsunderstanding how permanent storage works you don' need to understand absolutely every detail about how permanent storage works in order to use it for examplejust how the drive spins (assuming that it spins at allis unimportant howevermost platforms adhere to basic set of principles when it comes to permanent storage these principles have developed over period of timestarting with mainframe systems in the earliest days of computing data is stored in files you probably know about files already because every useful application out there relies on them for examplewhen you open document in your word processoryou're actually opening data file containing the words that you or someone else has typed files typically have an extension associated with them that defines the file type the extension is generally standardized for any given application and is separated from the filename by periodsuch as mydata txt in this casetxt is the file extensionand you probably have an application on your machine for opening such files in factyou can likely choose from number of applications to perform the task because the txt file extension is relatively common internallyfiles structure the data in some specific manner to make it easy to write and read data to and from the file any application you write must know about the file structure in order to interact with the data the file contains the examples in this use simple file structure to make it easy to write the code required to access thembut file structures can become quite complex files would be nearly impossible to find if you placed them all in the same location on the hard drive consequentlyfiles are organized into directories many newer computer systems also use the term folder for this organizational feature of permanent storage no matter what you call itpermanent storage relies on directories to help organize the data and make individual files significantly easier to find to find particular file so that you can open it and interact with the data it containsyou must know which directory holds the file directories are arranged in hierarchies that begin at the uppermost level of the hard drive for examplewhen working with the downloadable source code for this bookyou find the code for the entire book in the bp