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Input/Output, Physical Format, and Logical Layout

Computing often works with persistent data. There may be source data to be analyzed, or output to be created using Python input and output operations. The map of the dungeon that’s explored in a game is data that will be input to the game application. Images, sounds, and movies are data output by some applications and input by other applications. Even a request through a network will involve input and output operations. The common aspect to all of these is the concept of a file of data. The term file is overloaded with many meanings:

• The operating system (OS) uses a file as a way to organize bytes of data on a device. It’s the responsibility of application software to make sense of the bytes. Two common kinds of devices offer variations in terms of the features of OS files:

  • Block devices such as disks or solid-state drives (SSDs): A file on this kind of device can seek any specific...