Elaborate on the difference between FAT16 and FAT32

Time:2021-12-4

Before describing the fat file system, we must know what fat is? FAT(File   Allocation   Table) means “file allocation table”. As the name suggests, it is a table used to record the location of files. It is very important for the use of hard disk. If the file allocation table is lost, the data on the hard disk will not be used because it cannot be located. Different operating systems use different file systems. Among the commonly used operating systems on personal computers, MS-DOS   FAT16 is used for version 6. X and below; OS / 2 uses HPFS; Windows   NT uses NTFS; And MS-DOS   7.10 and rom-dos   7.10 FAT16 and FAT32 are also provided for users to choose. Among them, FAT16 and FAT32 file systems we contact most.
1、 FAT16 file system  
     FAT16 uses a 16 bit space to represent the configuration file of each sector, so it is called FAT16.  
     FAT16 is inherently limited. Therefore, after each partition exceeding a certain capacity, the cluster size used by FAT16 must be expanded to adapt to larger disk space. The so-called cluster is the allocation unit of disk space, just like the bookshelves in the library. Each file to be saved to disk must be configured with a sufficient number of clusters before it can be saved to disk. The relationship between FAT16 partitions and cluster size is shown in the following table:  
Partition size        FAT16 cluster size  
16MB-127MB    2KB 
128MB-255MB   4KB 
256MB-511MB   8KB 
512MB-1023MB  16KB 
1024MB-2047MB 32KB 
     If you store 50kb files in a 1000mb partition, because the cluster size of the partition is 16kb, it needs four clusters. If it is a 1KB file, it must also be stored in a cluster. Can the remaining space in each cluster be used? The answer is no, so when using disk, you will lose some disk space more or less.  
It can be seen from the above that FAT16 file system has two biggest disadvantages:  
(1) The disk partition can only be up to 2GB. At present, as long as you buy a computer, the hard disk size must be at least 2GB, and hard disks of 3.2GB and 4.3GB or more can be found everywhere, and they are good and cheap. FAT16 file system can not adapt to the current high-capacity hard disk, and must be divided into several disk spaces. The size of the partition disk involves the problem of clusters, which has a great impact.  
(2) The size of the cluster used is not appropriate. Imagine that if a file with a size of only 1KB is placed in a 1000mb disk partition, its space is not 1KB, but 16kb, which is a waste of 15KB! At present, most popular HTML files are 1KB and 2KB in size, and dozens of HTML files are often used to make a website. If you have 100 such small files on your hard disk, the disk space you waste can range from 700kb (511MB partition) to 3.1mb (2047mb partition).  
     These two problems often make users hesitate in the choice of “how large partition can save space and make the use of hard disk more convenient and effective”.
2、 FAT32 file system  
     In order to solve the problems of FAT16, FAT32 system is developed. FAT32 uses 32-bit space to represent the configuration file of each sector. A single partition that can be used by FAT32 can reach 2TB (2048gb) at most, and the cluster size that can be used by partitions of various sizes is also appropriate. The above two advantages make the use of hard disk more efficient. The sizes of partitions and clusters are summarized as follows. We can make a careful comparison:  
Partition size        FAT16 cluster size   FAT32 cluster size
16MB-32MB       2KB           I won’t support it
32MB-127MB    2KB         512bytes
128MB-255MB   4KB         512bytes 
256MB-259MB   8KB         512bytes 
260MB-511MB   8KB         4KB 
512MB-1023MB  16KB        4KB 
1024MB-2047MB 32KB        4KB 
2048MB-8GB      I won’t support it        4KB  
8GB-16GB        I won’t support it        8KB  
16GB-32GB       I won’t support it        16KB  
Above 32GB        I won’t support it        32KB  
     Under the condition that the current hardware can support, for example, if the 8GB hard disk is divided into a single partition, the size of the cluster used is only 4KB, which really saves a lot of space compared with the previous FAT16.
3、 Restrictions on FAT32 use  
     Seeing these advantages, you must be eager to convert FAT16 to FAT32. However, before conversion, pay attention to the following points:  
(1) Incompatible with other PC operating systems. Currently, MS-DOS is the only operating system supporting FAT32   7.10、ROM-DOS   7.10, FreeDOS and windows   2000 or above, while other operating systems cannot read FAT32 partitions at all. For example, you use MS-DOS   6. X and other old versions of DOS boot disk, the FAT32 partition in your hard disk will disappear out of thin air, and you can’t see this partition at all. In addition, if you want to use multiple boot to start a variety of different operating systems, it is recommended that you do not change the C: partition to FAT32. Because some operating systems will force you to install and boot from the main partition of C: if you change C: to FAT32 and the operating system does not recognize FAT32, you cannot boot.  
(2) Some disk tools and anti-virus software do not recognize FAT32, which may cause that after conversion, the disk tool software cannot process the FAT32 partition, and the anti-virus software will not recognize this file system and misjudge it as poisoning.  
(3) Some older versions of software cannot be executed in FAT32 partitions, such as office   95 et al.  
(4) Partitions smaller than 512MB are generally not allowed to be converted to FAT32. Although we found from the previous list that partitions smaller than 512MB only use clusters with the size of 512bytes, in windows   98, you can only convert partitions above 512MB. If you want to convert a partition between 32MB and 512MB, you must use the / min command in cvt.exe, such as CVT   D:  / CVT32  / Min, or fdisk  / FPRMT。
(5) Disk compression cannot be performed in FAT32 partitions, even if windows is used   Disk compression in 98 also doesn’t work.  
(6) If your motherboard BIOS supports the “suspend to disk” function, please turn this function off, because it cannot be used in FAT32 partition.  
(7)Windows   The conversion tool provided by 98 can only convert FAT16 to FAT32, and can no longer convert from FAT32 to FAT16. The only way to convert back is to re partition, format, and then reinstall the system and application software.  
     To convert from FAT32 to FAT16, you can also use a tool: partition of PowerQuest   Magic   3.0 or above. This is a set of software that allows you to freely change partition size and file system without damaging disk data. You can use this software to convert FAT32 to FAT16 without reformatting your favorite hard disk. If you don’t have the software, you should have the idea of “ready to regret”, please make a backup before FAT16 is converted to FAT32. At the same time, we remind you that if your computer configuration is not very high (i.e. not p Ⅱ or CPU of the same level), it is best not to convert the partition table to FAT32, because this will affect the reading speed of the hard disk.