Boris wrote:
Well, I made a Linux Live DVD using the Debian distribution, and booted
into Debian.
I selected Files, and Debian showed the Macintosh HD, but also gave a
notification that the folder contents could not be displayed.
I then went to Terminal to see if I could do anything there. I just
entered 'man ddrescue' to see if the manual had help for ddrescue
commands. Nope. I also entered 'man help' and got a whole list of
commands with syntax.
The Debian distribution that I got said it had ddrescue package. Maybe
not. Maybe I'll give it another try with Knoppix.
But if this distribution doesn't recognize the Macintosh HD folders, I
wonder if ddrescue will see them.
Here are relevant screenshots:
https://postimg.cc/gallery/2k7wuwtcs/
I set up a real hard drive with a Mac image on it.
And I was shocked when the file manager in Linux (Ubuntu 18.04)
understood the multiple partitions on the Mac disk and actually
mounted the partition I selected. This is the release I used.
more /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=18.04
DISTRIB_CODENAME=bionic
DISTRIB_DESCRIPTION="Ubuntu Bionic Beaver (development branch)"
In the /etc/mtab file, this is the entry for the mounted file system.
(Mounted by clicking the partition, in the name of science.)
Using the "remount" command, you might be able to change the "-o rw"
to "-o ro" and make the partition read only while working on it. It doesn't
hurt my setup, because my disk is a copy of an existing .img of the thing.
# This is not a command. This is a line in mtab, recording the mount OP.
# The parameters suggest a full-featured manual command line operation instead.
/dev/sda18 /media/ubuntu/MacBak hfsplus rw,nosuid,nodev,relatime,umask=22,uid=999,gid=999, nls=utf8 0 0
If done manually, this is approximately what you'd do. The first actual
HFS+ partition on the Mac disk is 9, and this one is about half
way out. The Mac disk might be able to handle 20 partitions or so.
At a guess.
# make a mount point in slash
sudo mkdir /media/ubuntu/MacBak
# mount it
sudo mount -t hfsplus -o ro,nls=utf8 /dev/sda18 /media/ubuntu/MacBak
Now, you got an "I/O error" at your top level, whereas
I got "Permission Denied", and you can see from the goofy
ownership displayed on the screen, why that happened.
https://s22.postimg.cc/xv1ict42p/my_mac_permissions.gif
In this thread, you can see the conclusion was, that
some flavor of ddrescue run is called for.
https://unix.stackexchange.com/quest...aged-hard-disk
A brief mention of the versions of ddrescue is made here.
https://www.cgsecurity.org/wiki/Damaged_Hard_Disk
# compare the versions here, to the version of gddrescue
# offered in your package manager.
http://download.savannah.gnu.org/releases/ddrescue/
# Version 1.23 was released Feb 2018.
ddrescue-1.23.tar.lz
My copy of Ubuntu offers version 1.22 .
https://s22.postimg.cc/e2zcdcsgx/synaptic_offers.gif
After it's installed, the Properties further down
shows the manual page is "ddrescue".
man ddrescue
*******
You can use the "smartmontools" package to get smartctl.
sudo smartctl -a /dev/sda
That will dump info like this. This is actually a good
disk, so the reallocated is still "0". This has nothing to
do with estimating how many "I/O errors" are present,
because just one I/O error in a file allocation table,
is going to cause havoc.
https://s22.postimg.cc/y059mhyj5/Smart_Mon_Tools.gif
After you've made two safety copies of the disk, you can
experiment with tools like "Disk First Aid" from a Mac
installer CD, and try and repair it. But only work on a
copy, not on the original ("sick") disk.
Paul