[mythtv-users] OT DVD ripping software

[Simon Hobson]

I realise this is dragging an old thread from the grave ...


On 28 Oct 2014, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:

> dd does not stop on block errors, or retry errored blocks.  I have a
> number of bad DVD-R disks, so I just tried dd on one.  This is the
> result:
> 
> root at mypvr:/mnt/vid3/video/r/optical disk recovery# dd if=/dev/cdrom
> of=VD00218.iso
> dd: error reading â/dev/cdromâ: Input/output error
> 8917400+0 records in
> 8917400+0 records out
> 4565708800 bytes (4.6 GB) copied, 337.086 s, 13.5 MB/s
> root at mypvr:/mnt/vid3/video/r/optical disk recovery# ls -al VD00218.iso
> -rw-r--r-- 1 root root 4565708800 Oct 28 14:01 VD00218.iso
> 
> As you can see, dd copied the DVD to an image file, despite errors. It
> took around the same time as copying a disk without any errors.  It
> did give the one final error message, which is easy to miss - I did
> this time until I looked hard.  I actually did not see the error until
> I had copied the text and pasted it into this email.

It must vary between versions of dd, or perhaps it depends on the source ?

Yesterday at work I needed to do a very quick test to see if a hard drive (640G) was OK in a laptop :

# dd if=/dev/sda of=/dev/null bs=1024k
<loads of console error messages regarding ata1.00>
dd: reading `/dev/sda': Input/output error
20207+1 records in
20207+1 records out
21189169152 bytes (21GB) copied. 304.573 s, 69.9 MB/s

It most definitely stopped on input device error, and reported as such.