====== Modifying Filing System (MFS) (Functions/Subroutines/Programs) ====== ====== ====== ==== Created at 20 AUG 1998 04:12PM ==== Attached is the MFS book from the Advanced Revelation Developer Series in .PDF format. Use Adobe Acrobat to read the document.[] (To save, rather than launch, this file, use a right-click.) [[http://www.revelation.com/o4wtrs/KB_Articles/KB0169_files/Mfs.PDF|{{kb0169_1.png}} ]]   This book describes Advanced Revelation's MFS (Modifying Filing Structure) technology.  The use of MFSs is a powerful and innovative means for developers to gain low-level control over file input and output operations.   MFSs are an outgrowth of Advanced Revelation's approach to modularized filing systems.  Unlike traditional database management systems, Advanced Revelation is not bound to specific filing structures.  Instead, Advanced Revelation uses a standard protocol for file access, and a series of base filing systems (BFSs) to translate this protocol into the data management requirements of a variety of different structures.   The result is that Advanced Revelation provides to developers a completely open architecture.  Programmers are able to control data access all the way from the application (window) level down to the filing system level.   This book focuses on the ability of developers to add a modifying layer to a base filing structure.  In effect, an MFS adds functionality without requiring the developer to change the underlying base filing system.   **FOLLOWING IS THE TABLE OF CONTENTS** **Introduction                                                                                                                               ** About this Book                                                                                                                       MFS Definition                                                                                                                         MFS vs BFS                                                                                                                            MFS Applications                                                                                                                     System MFSs in Advanced Revelation                                                                                      **Programming an MFS                                                                                                               ** MFS Basics                                                                                                                             Filing System Access                                                                                                               MFS "Trapping" Mechanism                                                                                                      The MFS Shell                                                                                                                          MFS Arguments                                                                                                                       Dispatch Routine                                                                                                                      File Operation Logic                                                                                                                 Call to Next MFS                                                                                                                      Return from the BFS                                                                                                                 Compiling and Cataloging the MFS                                                                                           MFS/BFS Independence                                                                                                           **Installing an MFS                                                                                                                      ** Manual MFS Installation                                                                                                            Installing an MFS Using an R/BASIC Program                                                                            Dynamically Installing or De-installing an MFS                                                                            Installing an MFS on a Volume                                                                                                  **MFS Programming Notes                                                                                                          ** Accessing the MFS                                                                                                                  Accessing a File from Within an MFS                                                                                        Disabling a Function from within an MFS                                                                                   Passing Data to an MFS                                                                                                           INSTALL Call                                                                                                                            FLUSH Call                                                                                                                              SELECT and READNEXT Calls                                                                                                 OPEN.FILE Call and File Handles                                                                                              Accessing the Advanced Revelation File Name                                                                          Locks and Unlocks                                                                                                                   Media Calls                                                                                                                              Record Count                                                                                                                           **MFS Operations Reference                                                                                                        ** **MFS Operations Glossary                                                                                                          ** **Appendix 1: FILES and VOLUMES Files                                                                                    ** **Appendix 2: System MFSs                                                                                                         ** **Appendix 3: Performance Issues for an MFS                                                                             ** **Appendix 4: MFS Constants                                                                                                       ** **Appendix 5: MFS Codes Quick Reference                                                                                  ** **Appendix 6: Accompanying Software                                                                                        **