Files and folders

A file is a set of data stored in external memory under a name; on a disk data can be stored only as files. A file name has two parts separated by a dot: the own name and the extension (.txt – text, .docx – Word document, .xlsx – spreadsheet, .jpg and .png – pictures, .mp3 – audio, .mp4 – video, .pdf, .zip – archive, .exe – program). The characters \ / : * ? " < > | cannot be used in a name, which may be up to 255 characters; in Windows names such as CON, PRN, AUX, NUL, COM1 and LPT1 are reserved. Folders (directories) group files; they can hold other folders, so a layered, tree-like structure appears. Two files with the same name cannot be in one folder, but can be in different folders. To find a file we write the sequence of folders from the disk – the path, for example D:\Maktab\Informatika\Hisobot.docx. The file system (NTFS, FAT32, exFAT) defines how data is placed on the disk; a file is stored in clusters, so the space it takes is rounded up to a multiple of the cluster size. Before opening an unknown file, especially .exe, scan it with an antivirus, and switch on the display of extensions: “rasm.jpg.exe” is really a program.