FAT or FAT32

[JATO]

I have a 512 CF card that I formated within windows XP using FAT32. My other 256k card I noticed is using FAT (16?). My FAT32 card seems to be working OK, has anyone ever had any problems using FAT32? Is one perfered over the other as far as the CF card is concerned. I would guess most people just use the camera to format the card, yes?

JATO
www.jatobservatory.org

[PacAce]

JATO wrote:
I have a 512 CF card that I formated within windows XP using FAT32. My other 256k card I noticed is using FAT (16?). My FAT32 card seems to be working OK, has anyone ever had any problems using FAT32? Is one perfered over the other as far as the CF card is concerned. I would guess most people just use the camera to format the card, yes?

JATO
www.jatobservatory.org

Yes, I would assume most people would format their CF cards in the camera...less chance of having problems that way.

I assume you're using the FAT32 formatted cards in your 10D (or one of the other cameras that support it--not all cameras do, btw). The only time FAT32 really makes a difference is if you want to use a card with a capacity greater than 2 GB. If it's less than that, FAT or FAT32, doesn't make a diff.

[JATO]

Thanks PacACe

[MediaMagic]

Hi Jato,

As PaceAce has mentioned, the difference you will notice as the photographer would be minimal or non existent. To understand the difference in the two formatting systems we have to delve into the wonderful world of Sectors and Clusters.

FAT is the acronym for File Allocation Table and when written in terminology as "FAT" with no number appended refers to FAT16. A "sector" is the smallest amount of space on a disk that can be accessed and is typically 512 bytes. Individual sectors, though, are not used. For example, a 20Gig HD having each sector managed individually would contain roughly 40million references to the sectors which is a bookkeeping nightmare as well as performance drain.

Instead, a file on a disk is stored in a series of clusters and each cluster contains a specific number of sectors. The number of sectors each cluster contains depends upon the size of the disk and the type of FAT system used. The larger the disk, the larger the size of the clusters. All floppies use FAT12 which is the allocation system originally used with the first versions of DOS. FAT16 (FAT) appeared with DOS 3.x and is still in use today. With the advent of WIN95 SR2(Dos7.1)FAT32 became another option. There are several others including VFAT, and NTFS but for our discussion, we'll use just FAT and FAT32.

Now, enough of the geek history lesson. What is really happening behind the scenes? Okay. As mentioned earlier, a sector is the smallest space on a disk that can be accessed. And, although a cluster is broken into sectors, a cluster is the smallest amount of space that can be allocated or assigned to a file. The file must be assigned an integer number of clusters. It can't be assigned in fractions such as 3.2, it would have to be assigned either 3 or 4.

So, lets say we have a cluster size of 8k, containing 8,192 bytes (16 sectors), an 8,000 byte file uses one cluster (8,192 bytes on the disk so wasted space is minimal) but a 9,000 byte file uses two clusters (16,384 bytes on the disk). The difference of the allocated space, 16,384, and the actual needed space is 16384-9000=7384 bytes. This wasted space is called "slack". So, if we can keep the cluster size at 4K (4096 bytes, 8 sectors) the same 9000 byte file can be stored in three clusters using 4096 X 3 = 12288 bytes, resulting in only 3288 bytes of wasted space. So, the amount of slack is reduced. Each and every file, unless it happens to contain the exact number of bytes as a cluster, contains wasted space. With a CF card containing tens or hundreds of pics (each pic is a file) the slack can add up. The goal is to minimize this wasted space.

typically though, when disks are large, they are using cluster sizes of 32k or 64k, so the amount of slack can rise to a large percentage of the overall disk space or, in other words, become HUGE

Now, this is where the difference in FAT and FAT32 come into play. Basically, FAT32 can more effeciently assign and manage the cluster sizes by keeping the cluster sizes smaller and hence less slack. There are many more differences, but again, for our purposes, it is sufficient to say that there is usually less wasted space from "slack" on a disk formatted with FAT32 than with FAT16. It may be possible to take that extra shot with a FAT32 card because of the space saved with more efficient cluster management.

Hope this brief dissertation helps.
David

[Phil Hall]

I find that FAT32 will not work on the 1D. I usuaaly get 191 RAW shots on a 1 gig microdrive. Sometimes I manage to shoot 240 shots ( 240x 4,1= 1gig) but then have difficulty retrieving the last few shots.

[CyberDyneSystems]

Well done MediaMagic! :D

A very informative post,.. I see I am not the only Computer Geek on this forum :D