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It seems that there are many tools out there for Mac OS X that test a hard drive for bad blocks by doing a Read/Verify pass. That is, they read a block, then read it a second time, and verify that both reads yielded the same results.

I need a tool that does a non-destructive Read/Write/Verify pass. It should read each block, write those same contents back out, and then read it again to verify. That way every block gets written, giving the hard drive a chance to spare out bad blocks. But since the same contents that were just read get written back out, it doesn't destroy data that wasn't already lost.

I'm aware of several tools that can do Read/Verify, but I'm not aware of any that do Read/Write/Verify. Are there any tools that do what I want?

Unix / open source tools that compile and run on Mac OS X are fair game too.

quack quixote
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Spiff
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3 Answers3

19

You might want to have a look at badblocks(8), a command-line tool from GNU/Linux. There is a port for Darwin, which you can get from MacPorts:

sudo port -v install e2fsprogs

Having a look at the manual, you can read the -n and -w options' paragraphs:

-n Use non-destructive read-write mode. By default only a non-destructive read-only test is done. This option must not be combined with the -w option, as they are mutually exclusive.

-w Use write-mode test. With this option, badblocks scans for bad blocks by writing some patterns (0xaa, 0x55, 0xff, 0x00) on every block of the device, reading every block and comparing the contents. This option may not be combined with the -n option, as they are mutually exclusive.

Hopefully this is what you are looking for.

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sirdharma
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1

The digilloyd disc tester does read/write/verify and is fabulous to boot.

More HERE

drewk
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0

Drive Genius

I'd like sirdharma's answer a I prefer command-line tools, though don't like the Macports requirement to install the multi gigabyte fat Xcode. If I could download a (for Lion) precompiled binary I would use that. I did continue my search with query "badblocks os x lion" and came along Pro Soft's Drive Genius. It turns out that I even purchased a license back in 2013.

Scan

The Scan function Drive Genius version 3 has two check boxes to enable write (and potential destructive) tests.

1. Spare bad blocks

It can instruct the hard drive to dereference the bad blocks in a matter of hours days. https://www.prosofteng.com/support/drive-genius-3/drive-genius-3-spare-bad-blocks

2. Extended scan

This verifies the read and write ability of every block. It isn't exceptional that this scan takes 1 week for a 1TB drive.

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Pro Backup
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