A logic file system is a mostly academic concept of a computer file system that attempts to merge traditional structured file systems with a relational database style interface to create a way for users to locate and process files by defining the properties of a file instead of defining a path and exact file name. The resulting logic file system would allow a user to specify information known about a file to essentially query the file system like a relational database in which the logic file system could return a single file or a list of matching files from which to choose. Some issues that a logic file system presents include accurately weighting properties used to define files, providing intuitive ways to narrow searches, and developing methods for user search queries that are easy to learn, understand and use. Being a largely research file system, most interaction is based on long command line inquiries with no graphical user interface (GUI) present. There is no industry-grade logic file system, with most research limited to a few prototypes, so the actual internal technical workings of such a system vary by implementation.
In most instances, a logic file system is described as combining hierarchical file system navigation, such as commonly is used on most computers, with web-style Boolean searches while maintaining a kind of relational database of different file properties that can be searched. The ultimate goal would be to allow a user to employ standard command line functions such as "mkdir" or "cd" in ways that are more imprecise than traditionally used. This would mean that, instead of using "cd" to change to a specified directory, the command could be followed by a formula, or query, that the file system runs to find directories matching the criteria provided. The result could be a single directory, if the query was specific enough, or it could be a list of many directories that can be further searched.
One of the challenges that implementing a logic file system presents is accumulating the properties used to define the files aside from their file names. If a large batch of photographs, for example, was copied into the file system, then the only properties that would be known about the images would be their names and file sizes. Locating a single image within thousands could be difficult if each image were not somehow tagged with some type of identifier, although some systems compensate for this by allowing a user to assign a property by creating a file directory in which to place the files.
One consideration when implementing a logic file system is the speed it takes to create new files. In a mostly empty system, this can be fairly easy. As the number of files grows, so does the amount of information the system must store to perform queries to find files. This means that, as the file system ages, it can suffer from a loss of performance.
