FAT: Difference between revisions
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Added basic exfat differentiation logic
| [unchecked revision] | [unchecked revision] |
m (For some reason, the first sector of a cluster was, according to this page, "first_sector_of_cluster = (cluster - 2) * fat_boot->reserved_sector_count + first_data_sector;". Corrected.) |
(Added basic exfat differentiation logic) |
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Line 12:
=== FAT 32 ===
FAT 32 was introduced to us by Windows95-B and Windows98. FAT32 solved some of FAT's problems. No more 64K max clusters! FAT32 is slightly misnamed, as the top 4 bits of the 32 bit cluster number are reserved, and were never used. If you want to call it FAT28 instead, then as the name suggests, the filesystem can handle a maximum of 256M clusters per partition. This enables very large hard disks to still maintain reasonably small cluster sizes and thus reduce slack space between files.
=== ExFAT ===
ExFAT is the filesystem used on SDXC cards, created by Microsoft. It is basically FAT32 with actually 32 bits per FAT entry, with minor extensions. Main article is [ExFat]
=== VFAT ===
Line 515 ⟶ 518:
'''The FAT type of this file system
<source lang="C">
if(total_clusters < 4085)
{
fat_type =
}
else ▼
{
▲ if(total_clusters < 65525)
}
else if (total_clusters < 268435445
▲ fat_type = 16;
{
}
▲ fat_type = 32;
{
fat_type = ExFAT;
}
</source>
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