DIYbanter - 3Tb HDD on an XP32 box?

DIYbanter (https://www.diybanter.com/)

- Electronics Repair (https://www.diybanter.com/electronics-repair/)

- - 3Tb HDD on an XP32 box? (https://www.diybanter.com/electronics-repair/595722-3tb-hdd-xp32-box.html)

3Tb HDD on an XP32 box?

What's the best I can do?

All the partition managers tried so far, offer a single partition just under
750Gb and no remaining unpartitioned space.

A 2Tb drive works just fine - I'd even settle for that from the 3Tb
one..........

I suspect that what you're running into is the 2.2-terabyte limit in
the standard PC Master Boot Record. This would correspond to 32 bits
worth of sectors (4 hexabillion) at 512 bytes each.

Probably, when your partition table is being built, the software
you're using is trying to read the hard drive size via the PC BIOS,
and the sector count is wrapping around past 4 billion. The program
ends up with (3 terabytes - 2.2 terabytes) worth of sectors, and so
you only get 750 GB.

I'm not an expert in the PC BIOS, but I suspect that the "read drive
sector count" call returns a 32-bit result, and the BIOS isn't smart
enough to clip (rather than wrap) at 2.2 terabytes. If that's the
case, no matter what program you use, you'll hit the same behavior.

There's probably a fix, although it won't be trivial. What you would
need to do is let the software partition the drive. If you want more
than one partition, delete the single 750-gig existing one and create
the smaller ones you want at first, and then create a final partition
which uses up the remainder of the 750 GB space.

Then go in with a sector-level disk editing program, and edit the
partition table by hand. Take a look at

https://en.wikipedia.org/wiki/Master_boot_record

You'd want to edit the "number of sectors in partition" value at
offset 12 (0x0C) for the last (or only) partition and set it to
"0xFFFFFFFF" (or slightly less than that) and store this entry. This
would expand that partition to 2.2 terabytes.

Save the MBR, reboot, and I think you'd find that you have more space
available.

HOWEVER: depending on how your PC accesses the drive, you could find
that Bad Things happen when it tries to write beyond the 2.2-terabyte
boundary - reads and writes might wrap around to the beginning of the
disk. For that reason, it would probably be safest to limit the total
size of the partitions you create to slightly less than 2.2 terabytes,
so that all of the subsequent I/O operations are compatible with a
32-bit sector-offset API.

3Tb HDD on an XP32 box?

"Dave Platt" wrote in message
...
What's the best I can do?

All the partition managers tried so far, offer a single partition just
under
750Gb and no remaining unpartitioned space.

A 2Tb drive works just fine - I'd even settle for that from the 3Tb
one..........

I suspect that what you're running into is the 2.2-terabyte limit in
the standard PC Master Boot Record. This would correspond to 32 bits
worth of sectors (4 hexabillion) at 512 bytes each.

Probably, when your partition table is being built, the software
you're using is trying to read the hard drive size via the PC BIOS,
and the sector count is wrapping around past 4 billion. The program
ends up with (3 terabytes - 2.2 terabytes) worth of sectors, and so
you only get 750 GB.

I'm not an expert in the PC BIOS, but I suspect that the "read drive
sector count" call returns a 32-bit result, and the BIOS isn't smart
enough to clip (rather than wrap) at 2.2 terabytes. If that's the
case, no matter what program you use, you'll hit the same behavior.

There's probably a fix, although it won't be trivial. What you would
need to do is let the software partition the drive. If you want more
than one partition, delete the single 750-gig existing one and create
the smaller ones you want at first, and then create a final partition
which uses up the remainder of the 750 GB space.

Then go in with a sector-level disk editing program, and edit the
partition table by hand. Take a look at

https://en.wikipedia.org/wiki/Master_boot_record

You'd want to edit the "number of sectors in partition" value at
offset 12 (0x0C) for the last (or only) partition and set it to
"0xFFFFFFFF" (or slightly less than that) and store this entry. This
would expand that partition to 2.2 terabytes.

Save the MBR, reboot, and I think you'd find that you have more space
available.

HOWEVER: depending on how your PC accesses the drive, you could find
that Bad Things happen when it tries to write beyond the 2.2-terabyte
boundary - reads and writes might wrap around to the beginning of the
disk. For that reason, it would probably be safest to limit the total
size of the partitions you create to slightly less than 2.2 terabytes,
so that all of the subsequent I/O operations are compatible with a
32-bit sector-offset API.

Pretty sure something nasty would happen if I tried for more than 2.2Gb
partition - but I can't even get that.

I was thinking more along the lines of 2x 1.5Tb partitions.

3Tb HDD on an XP32 box?

In article ,
Ian Field wrote:
Pretty sure something nasty would happen if I tried for more than 2.2Gb
partition - but I can't even get that.

I was thinking more along the lines of 2x 1.5Tb partitions.

That _may_ be workable, but you're probably going to have to do
more math, and become more familiar with the PC Master Boot Record
and how to hack it.

Setting up the MBR to work in LBA (logical block address) mode,
rather than C/H/S, would probably make things easier.

Again, it's going to depend a lot on your PC and its device drivers.
If it's capable of accessing the drive in LBA48 mode (with a 48-bit
logical block address) you may get away with it. If not, you may be
stuck with 2.2 terabytes at most.

3Tb HDD on an XP32 box?

On Friday, August 25, 2017 at 11:10:02 AM UTC-7, Ian Field wrote:
What's the best I can do?

All the partition managers tried so far, offer a single partition just under
750Gb and no remaining unpartitioned space.

A 2Tb drive works just fine - I'd even settle for that from the 3Tb
one..........

Thanks for any help.

If you can live with it as non bootable data only, put it in a USB3 enclosure and use it that way. XP is fine with 3tb USB drives.

GÂ²

3Tb HDD on an XP32 box?

wrote in message
...
On Friday, August 25, 2017 at 11:10:02 AM UTC-7, Ian Field wrote:
What's the best I can do?

All the partition managers tried so far, offer a single partition just
under
750Gb and no remaining unpartitioned space.

A 2Tb drive works just fine - I'd even settle for that from the 3Tb
one..........

Thanks for any help.

If you can live with it as non bootable data only, put it in a USB3
enclosure and use it that way. XP is fine with 3tb USB drives.

Someone gave me one of those they'd dropped on the USB connector - figuring
out where all the ripped up tracks went became a "back burner" project.

3Tb HDD on an XP32 box?

On 08/26/2017 02:21 PM, Ian Field wrote:

wrote in message
...
On Friday, August 25, 2017 at 11:10:02 AM UTC-7, Ian Field wrote:
What's the best I can do?

All the partition managers tried so far, offer a single partition
just under
750Gb and no remaining unpartitioned space.

A 2Tb drive works just fine - I'd even settle for that from the 3Tb
one..........

Thanks for any help.

If you can live with it as non bootable data only, put it in a USB3
enclosure and use it that way. XP is fine with 3tb USB drives.

Someone gave me one of those they'd dropped on the USB connector -
figuring out where all the ripped up tracks went became a "back burner"
project.

I just got a couple of the Plugable ones (2.5/3.5 inch) and they work
great--it really cut down my backup/restore times. I built myself a new
Qubes box (Thinkpad T430, 16G, 1T SSD) which required restoring all my
VMs from backup. (I could have used dd and then resized the partition
and file system, but that's a pain on an encrypted partition.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

3Tb HDD on an XP32 box?