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Old Aug 14, 2003, 8:32 AM   #11
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Join Date: Jun 2002
Posts: 823

Vox, here's a quote from my original post when I had SM format problems:

Both cards show FAT(16) formatting.
The good card shows 32,768 bytes used and 65,454,080 bytes free with 65,486,848 bytes total.
The bad card shows 2,048 bytes used and 65,258,520 bytes free with 65,261,568 bytes total.
With no info on the cards, the bytes used seem to indicate a difference in cluster size. As FAT is what was displayed for both, I suspect that both FAT12 and FAT16 would be reported the same way.

When attempting to duplicate these stats using DOS, I approached an error message stating that I couldn't use the next cluster size that would get me closer to those specs (can't remember what it was right offhand). What do you think?
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Old Aug 14, 2003, 12:07 PM   #12
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Posts: 2,162

Interesting numbers, but it's difficult to explain but I'll have a go. Forget cluster sizes to start with, if the numbers are real, they mean so much was taken up with writing the tables that this becomes unused space. Since space is an integral number of clusters of unit size, it might be true to say that used space for a large cluster size will allways be less than a cluster.

The bad card suggests it's used 1 cluster worth for the empty FAT. Lg you haven't said what size in Mb these cards are?

Here's Winhex data for a Virgin new never been in camera oem 8Mb SMcard:

FAT12, 7.8Mb free space (8,167,424 bytes), bytes/cluster:8,192 Bytes per sector: 512, Free clusters 997, Total clusters: 997

A used in camera 4Mb SM card:

FAT12, 3.9Mb free space (4,059,136 bytes), bytes/cluster:4,096, Bytes per sector: 512, Free clusters 991, Total Clusters 993

A used in camera 16Mb SM card:

FAT12, 15.5Mb free space (16,203,776 bytes), bytes/cluster: 8,192, Bytes per sector:512, Free clusters: 1,978, Total clusters: 1,995

A virgin new never used in camera oem 64Mb Compact Flash Card:

FAT16, 60.8Mp free space (63,745,024 bytes), bytes per cluster: 1,024, Bytes per sector:512, Free clusters: 62,251, Total clusters:62,251

A used in camera 128Mb SM card:

FAT16, 125Mb free space (131,006,464) bytes, bytes per cluster: 16,384, Bytes per sector:512, Free clusters: 7,996, total clusters:7,996

So there's the big picture for Smartmedia (except the CF 64Mb). The default cluster size increases with card Mb and the FAT12/16 changeover is above 16Mb. Even my smallest card was using a 4K cluster size. I'm fairly happy with the WinHex figures. All my cards work! I've got some other CF where I've forced non-standard large cluster sizes in DOS- they work great in Movie, but more space waste for pics. Cheers VOX
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