The FAT File System Structure

The FAT (File Allocation Table) file system was first introduced with MS-DOS in the early 1980s and then extended several times to accommodate for larger disk volumes. The term FAT refers to the allocation housekeeping method used. FAT file systems use a single File Allocations Table (the FAT) to record which areas of a disk are occupied.

Please note that Microsoft owns several patents related to FAT Long File Names, which are used by default by RTFiles-32. These patents may make a license from Microsoft necessary to use library Rtfiles.lib or RtfilesX.lib. No such license is included with an RTFiles-32 license. If you own the RTFiles-32 source code, you can compile it such that no patented code is being used (on the compiler command line, define RTF_LFN_SUPPORT=0 and RTF_EXFAT_SUPPORT=0, see Include\Rtfcfg.h for details).

This section describes the structure of FAT volumes.

Introduction

Right Sectors, Sector Addressing, and Clusters

Right Logical Drives and Partition Tables

Right The Boot Record

Right The File Allocation Table and Cluster Sizes

Right Directories and Files

Right Long File Names

Down The ISO 9660 File System Structure