1. A method for updating data stored in a write once/read many memory, the method comprising the steps of: creating a complete virtual image of data stored in the write once/read many memory; updating data in the complete virtual image of the write once/read many memory and designating updated data in the complete virtual image; and writing designated updated data from the complete virtual image to the write once/read many memory, wherein said creating step creates a main journal to organize file information on the write once/read many memory, and creates file journals, each containing a self-describing extent header for providing address information to a next extent of the file, in correspondence to files stored on the write once/read many memory, and wherein said updating step adds extent headers to sequentially contiguous blocks of memory and updates file organization information in the main card journal in correspondence to each added extent.