learning objective in this we start to work with files secondary memory/files are not erased even when the power is turned off or in the case of usb flash drivethe data we write from our programs can be removed from the system and transported to another system we will primarily focus on reading and writing text files such as those we create in text editor introduction most of the programs we have seen so far are transient in the sense that they run for short time and produce some outputbut when they endtheir data disappears if you run the program againit starts with clean slate other programs are persistentthey run for long time (or all the time)they keep at least some of their data in permanent storage ( hard drivefor example)and if they shut down and restartthey pick up where they left off examples of persistent programs are operating systemswhich run pretty much whenever computer is onand web serverswhich run all the timewaiting for requests to come in on the network one of the simplest ways for programs to maintain their data is by reading and writing text files in this we start to work with files secondary memory/files is not erased even when the power is turned off or in the case of usb flash drivethe data we write from our programs can be removed from the system and transported to another system we will primarily focus on reading and writing text files such as those we create in text editor later we will see how to work with database files which are binary filesspecifically designed to be read and written through database software any program you write will involve readingwritingor manipulating data for this reasonit' especially useful to know how to handle different file formatswhich store different types of data for exampleconsider python program that checks list of users for access control your list of users will likely be stored and saved in text file perhaps you are not working with textbut instead have program that does financial analysis in order to do some number crunchingyou will likely have to input those numbers from saved spreadsheet regardless of your applicationit is almost guaranteed that inputting or outputting data will be involved page