Re: other partition corrupted if (32GB) FAT32 filesystem filled >= 29 GiB

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jorgen wrote:
Daniel B. wrote:

So, is anyone aware of this bug? Is there a fix?

Well, how big is the harddrive, and where on the drive is the fat partition located?

I thinking about the 28bit lba vs 48bit lba issue. If this is not in order, data corruption can/will occur if data is written beyond the 128GB boundary

So the maximum sector number that works should be 2^28 - 1? (And
2^28 = 2^8 * 2^20 = 256 * 1048576 = 268435456, right?)


It's a 250 GB (about 232 GiB) IDE/ATA disk (488379168 sectors).

The partition is from sector 202435128 to sector 269538569.

So yes, it looks like the partition goes past the 128GB limits.
(That's exactly 128.0 GiB, right?)

(And the C: partition that gets corrupted is right at the beginning
of the disk, right where writes would go if a sector number right
over the 29-bit threshold were stuffed into a 28-bit fields with
the high bits dropped.)


Is there any fix for Windows 2000?


Hey, something doesn't quite add up regarding where I start having
a problem:


269538569 - sector number of last sector in partition
-202435128 - sector number of first sector in partition
----------
67103441
+1
----------
67103442 - number of sectors in partition (and that's also the
FAT filesystem size per Linux's "file" command)


So after writing 29GiB, the highest written sector's number is at
least:


67103442 / 32 * 29 = 60812492 sectors of data

202525128 - starting sector
+60812492 - sectors for 29GiB
---------
263037660
-1
---------
263037659 - minimum sector number considering only data

263037659
+ 16375 - sectors in FAT 1
+ 16375 - sectors in FAT 2
---------
263070409 - minimum considering data and FATs (but
not root directory, and 32 reserved sectors)


Hmm. I expected that number to be a lot closer to 268435456.
It's still 5,000,000 sectors away.

Did I miscalculate something?

Would Windows likely be using higher sector numbers, leaving
lower-numbered ones unused? (This was all on a partition that I
reformatted before copying the 29GB to it.)

Thanks,
Daniel
.

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