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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Joined: 04 Jul 2017, 05:06

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
Posts: 4
Joined: 04 Jul 2017, 05:06

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: 4
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: 4
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

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