Updating xp embedded
Like NTFS, ex FAT can pre-allocate disk space for a file by just marking arbitrary space on disk as 'allocated'.
For each file, ex FAT uses two separate 64-bit length fields in the directory: the Valid Data Length (VDL) which indicates the real size of the file, and the physical data length.
When a file is accessed, the directory must be sequentially searched until a match is found.
For file names shorter than 16 characters in length, one file name record is required but the entire file is represented by three 32-byte directory records.
Most of the vendors signing on for licenses of ex FAT are either for embedded systems or device manufacturers that produce media that will be preformatted with ex FAT.
Each record in the directory is searched by comparing the hash value.This optimization is analogous to an extent in other file systems, except that it only applies to whole files, as opposed to contiguous parts of files.ex FAT is supported in Windows XP and Windows Server 2003 with update KB955704, Companies can integrate ex FAT into a specific group of consumer devices, including cameras, camcorders, and digital photo frames for a flat fee.(There are two VBR type regions, the main VBR and the backup VBR.) The checksum sector is a checksum of the previous 11 sectors, with the exception of three bytes in the boot sector (Flags and percent used).This provides integrity of the VBR by determining if the VBR was modified. Any corruption in the table could prevent files from being located because this table is used to convert the filenames to upper case when searching to locate a file. Multiple directory records are used to define a single file and this is called a file set.