Laurence said:
i just used Easus Diskcopy to copy from a 500Mb drive to a 2tb drive
with the hope of resizing the partitions afterwards to get more space.
But on completion no partitioning tool will give me any more space
because BIOS only recognizes the new drive as 500Mb - an exact image of
the old one.
what am i missing here?
many thanks
lol
http://forum.easeus.com/viewtopic.php?t=20010
"Sorry for the inconvenience"
Yeah, that about sums it up. What were they thinking ?
The information isn't exactly accurate. The MBR and HPA
are not directly linked. HPA or Host Protected Area is a
way to redefine the disk capacity. And you can even
"snip the end off an working partition" by setting an HPA
while the disk still has data on it.
http://en.wikipedia.org/wiki/Host_Protected_Area
"SET MAX ADDRESS"
To test HPA, I did the operations from Linux.
I did it from Linux, because unlike the other methods,
I could continue to read documentation in a web browser
at the same time.
It involved some variation of this.
hdparm --yes-i_know_what_i_am_doing -N p# /dev/sdX
http://linux.die.net/man/8/hdparm
Not all the command line options are documented, such as
the "yes..." one. You only find out about it later.
Examples here.
http://tinyapps.org/docs/wipe_drives_hdparm.html
Now the fun part:
1) Not all ports on the motherboard support HPA.
To protect against malware setting an HPA, the
Southbridge ports will block it at the BIOS level.
On my motherboard, only the add-on Jmicron chip and
attendent Jmicron BIOS code module, would not do anything
to stop an HPA. I used the Jmicron for my experiments. Since
the Jmicron in this case is IDE, I used an IDE to SATA adapter
to set the HPA on my SATA disk.
This is not an issue for you, because it looks like Easeus
has already demonstrated it works on that port :-( If the
BIOS had properly protected it, Easeus might have been
stopped dead. I have motherboards where no port will do HPA.
2) The docs for hdparm say you can only deliver one HPA
command to the drive per boot session. And that seemed
to be the case here. My first attempt, I screwed up the
command syntax, and no further attempt would work until
I rebooted. Maybe this is implemented at the disk level
but I can't be sure. I'd have to grab a copy of the ATA/ATAPI
spec and see if that was the case.
I was able to convert a 250GB drive to 6GB that way.
And convert it back to 250GB. (Took about three reboots.)
I don't think I checked the BIOS readout, to see if it
was reading the SET_MAX_ADDRESS value or not. But it certainly
worked that way in Windows (capacity detected as expected).
Windows thought I had a 6GB disk, when the HPA "SET MAX ADDRESS"
was set that way.
If you copy verbatim a 500GB drive to a 2TB drive, the partitions
would stay at 500GB, but the disk capacity would continue to
report 2TB. It's when the available tools report the capacity of
the drive as 500GB, you begin to suspect an HPA. And that's what
I'm going on here, is that a real capacity change has occurred.
And HPA is implicated.
Have fun (hey, thanks Easeus! Easeus FTW /sarcasm),
Paul
