Remapping Bad Sectors on a Drive

Question

Level 1

16 points

Remapping Bad Sectors on a Drive

Remapping bad sectors - back in the days of SCSI drives - you were able to do what was called a " low level format " which would in effect remap bad sectors on the drive.

I don't see a way to do this with newer software such as disk utility etc.

Example: a friend of mine accidentally tripped the cord to his hard drive in the middle of the drive writing to the disk. Of course this is bad. Remapping the bad sectors would insure that the drive was working properly and not use any potential bad sectors.

Q: How can we remap bad sectors on today's ata and sata drives?

Thanks in advance for your help - RevDave

G4 Dual 1.25, Mac OS X (10.4.8)

Posted on Mar 3, 2007 12:53 PM

Reply

Answer 1

Mar 3, 2007 1:25 PM in response to Rev Dave

You can zero the drive - this will identify and block out bad sectors.

Through Disk Utility, go to the Erase tab, and then click "Security Options". One pass of zeroes will be enough.

Matt

Reply

Answer 2

Rev Dave Author

Level 1

16 points

Mar 3, 2007 5:44 PM in response to Matt Clifton

You can zero the drive - this will identify and block
out bad sectors.

Through Disk Utility, go to the Erase tab, and then
click "Security Options". One pass of zeroes will be
enough.

Matt

Thank you Matt for your help. Sounds good, however I didn't notice anywhere that it said that putting zeros on the drive will map out bad sectors. Is there somewhere that I can read about this?

Reply

Answer 3

Mar 3, 2007 6:11 PM in response to Rev Dave

I don't know if it's anywhere in Apple's documentation, but it's a standard technician practice for that purpose. Here's what Dr Smoke says about it in his X Lab site:

The process of erasing a disk, partition, or volume by writing zeros to every bit on such is called zeroing. Zeroing finds bad sectors and maps them out of service, also known as sparing. When an attempt to write zeros to bad sectors fails, the bad sectors are both marked as occupied in the directory and added to the bad blocks file of the file system. Once the bad sectors have been spared, no attempt will ever be made to read-from or write-to them again.

Matt

2.5GHz|3.5GB G5, 1.5GHz|512MB PB12, iSight, 4G iPod Mac OS X (10.4.7)

Reply

Answer 4

Rev Dave Author

Level 1

16 points

Mar 4, 2007 6:18 AM in response to Matt Clifton

Thanks very much Matt - that answers it for me!

Reply

Answer 5

Rev Dave Author

Level 1

16 points

Mar 4, 2007 6:20 AM in response to Matt Clifton

Thanks very much Matt - that answers it for me!

Reply