Paul wrote:
Jim wrote:

Afternoon Paul, well this is looking more worrying as it only ever
seems to show up as 750 odd GB, having ran PTEDIT32 and testdisk i
took some screen shots and stopped because testdisk gave a message
saying not to go any further if disk size was reported wrong which it
is, below are the links for screen shots.

http://imageshack.com/a/img716/2622/34nm.jpg
http://imageshack.com/a/img593/9896/gk7c.jpg

I was being quite optimistic last night and thought if this went well
i will not have enough spare space to take stuff off so i bought
another 3TB Black last night, looks like i might have been kidding
myself

Jim


OK, it just occurred to me, the PTEDIT32 has a display of
on-disk CHS value. Yours is 97451/255/63. Doing the arithmetic
(roughly, by ignoring whether I'm supposed to be adding one to
one of those fields or whatever)

97451*255*63*512 = 801,561,761,280 --- 747GB

Oh, dear. So that's where the size is coming from. OK, I'm going
to have to shut down the PC, and plug in my 3TB drive now, for
comparison. Of course, it isn't GPT, so the comparison isn't exactly
valid.

Back in a moment...

Paul

OK, my 3TB disk uses the physical+virtual Acronis method.
The lower portion shows up as a 2TB disk, the upper, as 747GB.

The 2TB shows this for CHS

243201/255/63 = 243201*255*63*512 = 2,000,396,321,280

So that's consistent with the partitions defined in the lower MBR.

The upper part of the drive, has its own MBR, which the filter
driver makes to appear as a separate drive. And that one, not
so coincidentally, is

97451/255/63

as that's the left-over space being defined as a virtual drive.

*******

Now, in these, I don't see where any disk geometry for the whole
disk is stored.

http://thestarman.pcministry.com/asm/mbr/PartTables.htm

http://thestarman.pcministry.com/asm/mbr/GPT.htm

http://thestarman.pcministry.com/asm/mbr/W7MBR.htm

The last article, makes it sound like the partition
entries are fashioned, based on BIOS reported geometry.
But of course those numbers can't change, if the BIOS has
a brain fart and starts doing something different. However, the
total size of the disk can be passed as a different value, leading
to the truncation you're seeing.

So my best guess is, the BIOS is doing this somehow.

The EDD spec, doesn't look like it has any geometry in it,
fake or otherwise. And yet the Linux article I was looking
at, was claiming it was getting it from there.

http://t13.org/Documents/UploadedDoc...1386r0-EDD.pdf

The hwinfo output in Linux here, shows an EDD geometry. And maybe that's
related to what we're seeing in your case.

http://unix.stackexchange.com/questi...-in-the-system

I'll boot over to Linux now, and have a look at hwinfo.

*******

Well, stumped as usual. Still don't understand this stuff.

All I can suggest at this point, is to think carefully about
any changes made recently. Like BIOS changes just before
it could no longer mount.

Paul