[Bug-ddrescue] New tool that can help with some drive issues

[Scott Dwyer]

I have created a new tool, HDDSuperTool, which is a multi-purpose tool 
to work with hard drives. This tool is in no way related to ddrescue so 
I am not supplying a link, but you can find HDDSuperTool by performing a 
Google search. Up until now it was not worth mentioning here, but I have 
just recently added a couple features that could be beneficial to some 
that use ddrescue.

The first is the ability to set the read error control timer. This 
feature is not available on all drives, I think maybe 25% of the drives 
in my possession have this ability. But for the ones that do, it can 
help with speeding up recovery if there are lots of errors on the drive. 
It uses standard ATA commands to set the timer, and the timer is reset 
after a power cycle so it should be safe to use. The timer controls how 
long the drive will try before giving up on a read error. But you need 
to use the --ata-passthrough feature of my ddrescue patch for this to be 
effective. The reason seems to be that the Linux kernel likes to perform 
retries and even seems to have some sort of minimum timer for read 
attempts. Using the --ata-passthrough option bypasses these retries. The 
timer values may have different results on different drives. The lower 
you can set it and get good results the better, but if set too low for 
the drive it could mark readable sectors as bad. It is up to you to find 
the best setting for your case.

The second feature is only for Western Digital drives that suffer from 
unusually slow read speeds. These drives will seem to read in bursts and 
have very slow read speeds even in good areas. There are a couple 
patches that can be applied for this. These patches alter what is called 
the service area of the drive, so they could be considered dangerous. 
Use at your own risk! I have only tested them on one drive, but it was a 
very successful test.

Hopefully these features of the tool will help someone with their recovery.

Scott