Ubuntu

That sounds like the console screen-saver. Hitting the ctrl-key (or any other dead-key) should have brought it back. I can't see anything obviously wrong with what you did.

But I can't see your computer from here, I don't know what you truly did, or even the circumstances. I don't even know what folder you were in for instance -- that may have had something to do with where the logfile went. Don't know how you booted the system -- hopefully sdb wasn't the disk you'd booted from? I don't know what way the program terminated -- there is a vast, important difference between 'lots of bytes' and 'all the bytes'... and such and forth.

Yes, having gained a little more experience of ddrecue, I now think that was the case.

Booted from the Remix live CD which includes ddrescue.

I have since run it again and tried to change the '-f' option, but it wasn't having that as there was data already on the target.

Here is the returned result:

Initial Status (read from logfile)
rescued 0B, generated 0B,
Current Status
rescued: 264104MB, generated 1TB current rate:96206KB/s
Oppos: 1TB, average rate: 107MB/s
Finished
My intention now is to become more familiar with the Remix console and ddrescue. In particular to explore the path system for storing the log file in an umounted drive. I expect it just becomes part of the output file and is then written to the target as a whole. Also, I will re-examine the remaining options-perhaps I missed something obvious.
I do appreciate your help.
Regards Roy

---------- Post updated at 17:18 ---------- Previous update was at 08:36 ----------

I have come to the conclusion that ddrescue, or the Remix version if such, is incapable of writing an output to anything other than a completely fresh i.e. empty disk. Having put considerable effort and time into this. The -f option will not overwrite the data onto a healthy diskcontaining dataeven after a satisfactory completion.
I hope that it makes a better job of what is stated as it's primary purpose, but for simple disk cloning it is a no - no.

Moderator's Comments:

Please edit you post to use the default Font Size

What? Please...

I'm sorry, but this makes no sense. There's no difference between a completely fresh empty disk and a disk full of data, when you look at them as block devices as ddrescue does. And ddrescue works flawlessly.

You simply didn't get what's "-g" (or "--generate-logfile") for. True that the man didn't help you with too many words, I must admit. But please read here carefully:
GNU ddrescue Manual

With this "-g" option, ddrescue doesn't even try to copy: it tries to generate a logfile from a source and an already made (partial) copy.

Don't use the option "-g", and ddrescue will work for you.
HTH.
--
Bye

Thanks Lem - most interesting.

The Remix 'info ddrescue' is clearly very truncated and so I found your link most enlightening.

The one I previously read emphasises the need for a logfile and neither seem to tell how, or where to find the logfile. Nowhere, after numerous re-reads, is there any mention that using the '-g' option does not complete the job, but with the previously mentioned emphasis, it seems necessary to include the '-g' option. You seem to be telling me to make numerous passes to obtain these logfiles (just by appending <logfile*?> and to exclude the '-g' ??

dd does it all in only one pass.

I do hope that this makes sense to you. Your advice is much appreciated. Please note only 2 now ----->

Ok, let's start from the beginning.

To have a logfile, just use the optional [logfile] field.

For example (I think it's pretty self-explanatory):

Code:

# ddrescue -f /dev/sdx /dev/sdy /var/log/ddrescuelog

Just one pass. You're done.

About the "-f" option: ddrescue doesn't copy only from disk to disk: it copies from a standard file, a partition or a disk to a standard file, a partition or a disk. It can copy from a file to a partition, or from a disk to a file, or whatever you like. Now: if the destination is a device or a partition, so if it isn't a regular file, ddrescue will refuse to overwrite it without "-f" option: "it's for your own protection"(R). So you're right using it.

About the logfile: ddrescue is thought for situations where the origin is tipically a disk with some bad unreadable sectors. ddrescue task is to copy as much as possible, as quick as possible, with the least possible stress. But something won't be copied, usually. It won't be possible to read some sectors on the origin, and the corresponding sectors on the destination will be zero-filled. That's why a logfile is so relevant: to know what has been copied and what hasn't.
But you're using ddrescue just to clone a healthy disk, so your logfile (yes, have it, it won't harm) will be really tiny and not interesting.

About "-g" option: let's say someone used ddrescue to recover data from a failing disk and without a logfile (shame on him!). Now he has the origin, he has the (partial) copy, he hasn't got the logfile. Thanks God (well, thanks ddrescue) he can generate the logfile (well, an approximate logfile) even "ex post", with "-g" option: ddrescue -g origin alreadymadecopy /var/log/ddrescuelog. Of course this is not your case, so you're not interested at all in "-g" option, which makes ddrescue just compare an origin with a copy, and create a log about what has probably been done.

I hope we can get rid of those walls, now.
--
Bye

Lem my sincere thanks. It had occurred to me last night, that dropping the -g would probably solve my particular problem, having read your earlier post.
It must be difficult writing a manual to suit all levels of users, but I have re-read again, some of it and can see no way that it explains all that I needed to know and that you have explained so well. By a process of trial and error, if prepared to spend copious amounts of time, I would probably have made it do what I needed, but I also need to understand all the implications of the use and the full capabilities of ddrescue.
In the manual for example there are several example command lines or functions having multiple lines. I still don't understand whether these are supposed to called individually (i.e. one at a time), or may be called simultaneously by the use of shift + return keys at each line end and executed with a final return key?
Nowhere, is there an explanation of how to state the path for the log file and surely only advanced users would know where it should be filed?
I haven't been using Ubuntu for a full year yet and at the age of 75, maybe I don't pick things up as readily as youngsters, but I am putting a lot of effort into mastering it all.
Your comments have been most helpful, you have clearly devoted considerable time to helping out.
If you find the time to answer my final queries, it will be great. Many thanks. ---> look no wall!
Roy