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Like NTFS, exFAT can pre-allocate disk space for a file by just marking arbitrary space on disk as "allocated". For each file, exFAT uses two separate 64-bit fields in the directory: the valid data length (VDL), which indicates the real size of the file, and the physical data length.
File Allocation Table (FAT) is a file system developed for personal computers and was the default filesystem for the MS-DOS and Windows 9x operating systems. [citation needed] Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices.
File size is a measure of how much data a computer file contains or how much storage space it is allocated. Typically, file size is expressed in units based on byte . A large value is often expressed with a metric prefix (as in megabyte and gigabyte ) or a binary prefix (as in mebibyte and gibibyte ).
A basic data partition can be formatted with any file system, although most commonly BDPs are formatted with the NTFS, exFAT, or FAT32 file systems. To programmatically determine which file system a BDP contains, Microsoft specifies that one should inspect the BIOS Parameter Block that is contained in the BDP's Volume Boot Record .
One is the actual file size, and the other is the length of the data that has so far been written into the file. This is called the Valid Data Length (VDL) feature ...
Data is compressed in 16-cluster chunks (up to 64 KB in size); if the compression reduces 64 KB of data to 60 KB or less, NTFS treats the unneeded 4 KB pages like empty sparse file clusters—they are not written. This allows for reasonable random-access times as the OS merely has to follow the chain of fragments.
While storage devices usually have their size expressed in powers of 10 (for instance a 1 TB Solid State Drive will contain at least 1,000,000,000,000 (10 12, 1000 4) bytes), filesystem limits are invariably powers of 2, so usually expressed with IEC prefixes.
In computing, the BIOS parameter block, often shortened to BPB, is a data structure in the volume boot record (VBR) describing the physical layout of a data storage volume. On partitioned devices, such as hard disks, the BPB describes the volume partition, whereas, on unpartitioned devices, such as floppy disks, it describes the entire medium ...