I installed Linux on an old computer along with ddrescue. Instead of placing each broken hard drive in the internal bay, can I use an external docking station with ddrescue?

I'm hesitant to buy a docking station (or an S-ATA to USB adapter), as I was told it's better for recovery tools to directly access the HD through the S-ATA cable instead of USB. Is that true or is there no difference?

  • You have a greater chance of compatability if you directly communicate with a SATA HDD over SATA. You would have to explain what you mean by, "it's better", because something being better is subjective. However, provided the recover tool supports USB HDDs, you shouldn't have a problem. – Ramhound Mar 30 '17 at 16:58
  • Better as in reading or correcting the faulty blocks/sectors. – Doreo Mar 30 '17 at 18:14

What you were advised (i.e. you are better off connecting to a SATA port then via USB) is true, and unfortunately some other answers on here are incorrect.

While, for the most part, using an external USB dock will work just fine, this is not always the case. Occasionally the geometry of the disk is obscured/changed - particularly when using drives < 2TB (generally 512-byte-sized sectors for compatibility) and Advanced Format (4k-sized sectors) - this is something I have personally experienced so know to be true.

Further, by adding a USB interface, you are interfering with the ability of some programs to do low level calls which can be useful in recovering data/getting feedback from the drive.

An alternative which might be available to you (depending on your motherboard) would be to use an eSATA interface - eSATA, in effect, extends SATA outside the case of your system [with appropriate protections], and is almost identical to SATA.


I've done recovery with external adapters and it works fine. The only disadvantage is that the speed probably won't be as good as it would be using the internal bay. There's no difference otherwise — I usually use a cheap SATA to USB adapter to connect the drives.


Short answer is: "It shouldn't matter if it's SATA, SCSI, USB, IDE or whatever if you're doing sector copies"

Longer answer is, in my opinion, out of the scope of this topic and includes differences in the different types of USB controllers which have varying support for "special command", etc pass-through.

Then there is USB 3.0 standard which includes USB attached SCSI and works even better with device specific commands and oddities (command queuing, etc).

Any problems USB docks or drives have have usually to do with device specific commands and you usually run into them in programs like hdparm, etc - not with dd or ddrescue.

If you want to be a bit more safe, you'll go with a USB3 dock and use it with a USB3 controller.

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