Temporary file

Temporary files (in computer slang often referred to as temp files ) are files that are used by the operating system or other programs and are used for temporary storage of data to be processed by the same or another program. The outsourcing of the data is done to relieve the computer's memory or to the transfer of data to organize to another program. With the introduction of virtual memory the need for such relief is partially mitigated, however, in some applications that has grown in the past data to be processed volume, such as in image processing.

Normally, these temporary files will also be deleted by itself create program. Mostly Windows, unforeseen program crashes and improper implementations but lead to accumulate temporary files and even unnecessarily occupy even after a restart of the system memory on the hard disk. A manual or by automated software products available on the market adjustment for these so-called " file corpses " is problematic, since not so readily recognize that temporary files are actually still needed. A premature deleting a required file can still cause a malfunction of the software application or the operating system. Often these files can not be deleted because they are locked by the need of the program for other requests. Unix-like systems go this Problemarik out of the way by the contents of the / tmp directory is deleted during every boot.

Under Windows are often temporary files by the file name extension. Tmp indicated.

Windows, MS- DOS

Under Microsoft Windows, temporary files are stored specifically for the logged in user, that is, for each user there is a separate directory (" folder " ), where these files are stored. By default, this is a subdirectory of the user directory is used, which is determined by the environment variable USERPROFILE. ( This directory is possibly in Windows Explorer not visible, since this may be a " hidden folder ", which must be made ​​visible by adjusting the appropriate option. ) An adjustment of the location of these files is possible in principle (configuration via the registry ).

As a relic of the previous operating systems ( for example, MS -DOS and Windows 98), there is also the environment variables TEMP and TMP on the configuration of the directory for temporary files is possible. Some applications still refer to these definitions.

Temporary files are stored by some programs and in specific application-related folders, or in the current directory, so it is not altogether easy to get an overview of unneeded files to completely clean up.

Linux, Unix

The Filesystem Hierarchy Standard for temporary files in Linux are two types:

Careless handling of temporary files can especially lead to multi-user systems that support symbolic links to a security hole: Is the name of a temporary file predictable, under this name is a symbolic link can be dropped. If, subsequently, a program running that creates a temporary file with the same name, it may result in data loss or expansion of user rights. Therefore contain temporary file name is usually a randomly generated combination of characters.