Can I use TestDisk on a non LBA48 Mac?

How to use TestDisk to recover lost partition
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wnlewis
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Can I use TestDisk on a non LBA48 Mac?

#1 Post by wnlewis » 04 Jul 2017, 18:16

Before I go any farther I should make certain that TestDisk will or will not work on my G4 Sawtooth Macintosh. It is a non-LBA48 computer. So, (as I understand it) boot information must be in a partition that is 128 GB or less.

I have had a partition failure on a 750 GB Seagate hard drive.

I use both 10.4.11 and 9.2 operating systems on this computer.

The hardware overview is as follows:
Machine Name: Power Mac G4 (AGP graphics)
Machine Model: PowerMac3,1
CPU Type: PowerPC G4 (2.1)
Number Of CPUs: 1
CPU Speed: 1 GHz
L2 Cache (per CPU): 256 KB
L3 Cache (per CPU): 2 MB
Memory: 1 GB
Bus Speed: 100 MHz
Boot ROM Version: 4.2.8f1
Serial Number: SG9460FLHM1

Thank you for any help you have to offer.

Neal Lewis

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cgrenier
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Re: Can I use TestDisk on a non LBA48 Mac?

#2 Post by cgrenier » 05 Jul 2017, 06:07

I don't see how your data can be accessed if they are after the first 128 GB if the lba48 is not used...

wnlewis
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Re: Can I use TestDisk on a non LBA48 Mac?

#3 Post by wnlewis » 05 Jul 2017, 11:04

So it appears that it is not possible to use TestDisk to find or to restore the partition table? I believe I have the correct understanding?

Thank you.

Neal Lewis

wnlewis
Posts: 5
Joined: 04 Jul 2017, 05:06

Re: Can I use TestDisk on a non LBA48 Mac?

#4 Post by wnlewis » 05 Jul 2017, 11:39

If I put the drive into an LBA48 capable Macintosh, then TestDisk might be able to reconstruct the partition table? Or is that ability (to find and reconstruct the table) restricted by how the partitions were made originally?

Thank you.

Neal Lewis

wnlewis
Posts: 5
Joined: 04 Jul 2017, 05:06

Re: Can I use TestDisk on a non LBA48 Mac?

#5 Post by wnlewis » 24 Jul 2017, 02:59

M. Grenier,

I have tried a different approach.

I have installed a PCI card that has an LBA48 compliant controller. The computer sees the card as a SCSI card.

Even Macintosh computers that are not LBA48 compliant for ATA drives (and also run OS X) can still see drives that are larger than 128 Gb if the drive is SCSI.

I have put an LBA48 compliant adapter on the Ultra ATA drive that has the damaged partition table.

The adapter lets the ATA drive be read as an SATA drive by the the PCI card I installed.

When I boot from the disk that needs to be fixed and use TestDisk, TestDisk now sees the drive as the right size.

I am thinking of getting a second adapter card to put on a second Ultra ATA disk. That would let me boot from a disk without damage and run TestDisk from a good disk. Would that be advisable?

Thanks,

Neal Lewis

wnlewis
Posts: 5
Joined: 04 Jul 2017, 05:06

Re: Can I use TestDisk on a non LBA48 Mac?

#6 Post by wnlewis » 19 Jan 2018, 00:53

Pursuing my rather old topic, I have the Firmtek 1V4 SATA controller in place and Firmtek 1SC1 adapters that allow a PATA/IDE drive to be attached to the 1V4 SATA controller.

The G4 AGP Mac sees the 1V4 controller as a SCSI drive.

SCSI drives are not restricted to LBA 128 Gb or less on any Apple OS X system on the PCI bus. The restriction only applies to the IDE bus.

Therefore I am going to try what I originally proposed, to put TestDisk on a good hard drive, connect it to the 1V4 controller card, connect the PATA drive with the damaged partition to the SATA controller card and attempt to restore the partition.

Once the partition is restored it is my intent to use TestDisk to resize the partitions on the rescued disk and reduce the drive partitions to less than 128 Gb - say 120 Gb. That should allow the drives to operate on the IDE bus (which does have an LBA limit of 128 Gb or less) to successfully use the drives.

Please let me know if my logic is incorrect on what I should be able to do - not that it can actually be accomplished.

Thank you for your help.

Neal Lewis

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Re: Can I use TestDisk on a non LBA48 Mac?

#7 Post by cgrenier » 19 Jan 2018, 07:00

testdisk can not resize of a partition, use parted or gparted instead.

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