| 摘要 |
A computing device comprises a body of embedded software, such as an operating system, formed as a plurality of binary images for controlling operation of the device, wherein each image contains an independent file system containing a directory hierarchy and file list applicable to the contents of that image, and in which the computing device additionally contains a single merged directory hierarchy and file list applicable to the entire body of embedded software. The composite file system may be constructed before or after the images are embedded and embedded in the device in persistent storage such as NAND Flash EEPROM. Alternatively the composite file system may be constructed when the device is started up and be stored in RAM. The composite file system may be constructed by merging the directory hierarchy and file list of two or more of the images. When two or more versions of the same file are defined in the plurality of images each version may have a precedence order which may be embedded as metadata in the appropriate entry in the file lists and used to determine which file is accessible. Entries in the file list may also include a flag which can be set to indicate that that entry is to be ignored, or never ignored, for searching and listing purposes. |
