SolFS is is a virtual file system, stored in single file (or database record, file resource or just memory block). SolFS has all necessary functionality, that can be found in modern file systems, such as support for streams inside of files, file and stream encryption, compression, journalling (support for data integrity), keeping of last data access time, symbolic links etc. Using SolFS you can simplify or completely solve the problem of managing large number of supplementary files, needed to your application. Now your customers won't be confused by unknown files, populating their disk drive. Also the problem of accidential file deletion is solved: all files are kept in one place out of user's touch. When you use one file (file system storage) application maintenance and user support becomes much easier. When your application works with several data sets, linked with each other, it is important to keep all data in one file. In this case use of SolFS lets you guarantee integrity and completeness of data. Written in ANSI C, SolFS can be used as embedded file system for custom hardware platforms, adding transparent compression and encryption support to these platforms.