storing data in files in this considering how permanent storage works with applications deciding how to work with permanently stored content writing to file for the first time obtaining content from the disk changing file content as needed removing file from disk ntil nowapplication development might seem to be all about presenting information onscreen actuallyapplications center around need to work with data in some way data is the focus of all applications because it' the data that users are interested in be prepared for huge disappointment the first time you present treasured application to user base and find that the only thing users worry about is whether the application will help them leave work on time after creating presentation the fact isthe best applications are invisiblebut they present data in the most appropriate manner possible for user' needs if data is the focus of applicationsthen storing the data in permanent manner is equally important for most developersdata storage revolves around permanent media such as hard drivesolid state drive (ssd)universal serial bus (usbflash driveor some other methodology (even cloud-based solutions work finebut you won' see them used in this book because they require different programming techniques that are beyond the book' scope the data in memory is temporary because it lasts only as long as the machine is running permanent storage device holds onto the data long after the machine is turned off so that it can be retrieved during the next session in addition to permanent storagethis also helps you understand the four basic operations that you can perform on filescreatereadupdateand delete (crudyou see the crud acronym used quite often in database circlesbut it applies equally well to any application no matter how your application stores the data in permanent locationit must be able to perform these four tasks in order to provide complete solution to the user of course