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jlg432 · 08-14-2010, 01:34 PM

No one seems to have explained Fat / Fat16 / Fat32 etc.

I know most people that have roots to DOS/Windows probably understand these terms but I would like to explain these in a very general detail for those readers that do not understand.

FAT is an acronym for F(ile) A(llocation) T(able). This is a place reserved on the storage media and is used to map out the storage space of the media.

Originally storage media capacity was very small and the 16 bit structure to map the space efficiently was ample. Media space is usually broken up into 512 byte sectors (which is the smallest size) that are then grouped into clusters. A cluster (which is a group of sectors) is the smallest amount of space that can be assigned for storing data. The size of the cluster is determined by the amount of stage space available as well as the size of the File Allocation Table. FAT a.k.a. FAT16 only had a capacity to support storage up to 2 gigs in size. As the storage size increased so did the cluster size. For 1 gig to 2 gig storage the cluster size was 32k. This meant that the smallest space assigned for saving data was 32k in size. A small 15k file would still take the same space that a 31k size file would take which is 32k.

By using FAT32 the File Allocation Table is double in size and the cluster size remains small (4k in size) when using storage sizes from 512 megs to 8 gigs.
Storage sizes smaller than 512 should use Fat16.

So storage is being used more efficiently by using FAT32 when using storage sizes exceeding 512 megs up to 32 gigs.

FAT16 also limited the number of files that could be stored in the "Root" of the storage media which was approx 512 items.

See http://technet.microsoft.com/en-us/l.../cc940351.aspx for more info.

John

Note: The user space on the JB, JBL and ALP is part of the storage used by the device.

I am not sure what that total storage is but what we can use must be a just a partition assigned to the user. This user space on the JB shrunk when I added FW .35a because they added the Adobe Reader software to the unit. User space went from 110 megs to approx 90 megs. The ALP started at 90 megs as it already had ADE reader installed.

John

08-14-2010, 01:34 PM	#26
jlg432 Addict Posts: 237 Karma: 15786 Join Date: Apr 2010 Device: jetBook, ALP, Pandigital 7"Color(Black+ White), Kyros MID7015a	No one seems to have explained Fat / Fat16 / Fat32 etc. I know most people that have roots to DOS/Windows probably understand these terms but I would like to explain these in a very general detail for those readers that do not understand. FAT is an acronym for F(ile) A(llocation) T(able). This is a place reserved on the storage media and is used to map out the storage space of the media. Originally storage media capacity was very small and the 16 bit structure to map the space efficiently was ample. Media space is usually broken up into 512 byte sectors (which is the smallest size) that are then grouped into clusters. A cluster (which is a group of sectors) is the smallest amount of space that can be assigned for storing data. The size of the cluster is determined by the amount of stage space available as well as the size of the File Allocation Table. FAT a.k.a. FAT16 only had a capacity to support storage up to 2 gigs in size. As the storage size increased so did the cluster size. For 1 gig to 2 gig storage the cluster size was 32k. This meant that the smallest space assigned for saving data was 32k in size. A small 15k file would still take the same space that a 31k size file would take which is 32k. By using FAT32 the File Allocation Table is double in size and the cluster size remains small (4k in size) when using storage sizes from 512 megs to 8 gigs. Storage sizes smaller than 512 should use Fat16. So storage is being used more efficiently by using FAT32 when using storage sizes exceeding 512 megs up to 32 gigs. FAT16 also limited the number of files that could be stored in the "Root" of the storage media which was approx 512 items. See http://technet.microsoft.com/en-us/l.../cc940351.aspx for more info. John Note: The user space on the JB, JBL and ALP is part of the storage used by the device. I am not sure what that total storage is but what we can use must be a just a partition assigned to the user. This user space on the JB shrunk when I added FW .35a because they added the Adobe Reader software to the unit. User space went from 110 megs to approx 90 megs. The ALP started at 90 megs as it already had ADE reader installed. John Last edited by jlg432; 08-14-2010 at 01:44 PM.