Backup of a dead hard drive?

Question

linux

The hard drive died, I'm trying to make an image of a banal dd. When a hard drive stumbles upon a bad piece of disk, the program that accessed it hangs for 15 seconds, after which it returns an i / o error. During these 15 seconds, the disc makes repeated uncharacteristic sounds.
Question: how to reduce this period of time? Let's say if the block is not read in a second, go to the next block. And then the process reaches a place where everything is bad, and then it works at a speed of 1 mb / s or less.
OS - Ubuntu 10.10, the disk is connected via USB.

Answer 1

Then dd_rhelp is better. It uses ddrescue but doesn't shut up on bad sectors.

Answer 2

Perhaps in this case, the use of the ddrescue and dd_rescue utilities will help. There is a lot of information on the Internet about these programs. If necessary, I will look for your case.

Answer 3

Tweak kern.cam.da.default_timeout and kern.cam.da.retry_count down.

Answer 4

ddrescue, dd_rescue (these are two different programs)

Answer 5

Freezing helped some to revive the disk for a while, for example, the link alenacpp.blogspot.com/2006/07/blog-post_19.html

Answer 6

in such cases I start with testdisk