Boris wrote:
Paul wrote in news
Boris wrote:
Frank Slootweg wrote in newshbhlg.ri4.1@ID-
201911.user.individual.net:

Boris wrote:
[...]

[N.B. Others have already commented on the need for the Windows system
to 'see' the disk at all, i.e. as a disk, not (yet) the filesystem(s)
on the disk, so I'll skip that.]

She has not yet installed HFS+/HFSExplorer.
In a similar situation - also a daughter :-) - I (successfully) used
'Paragon HFS+ for Windows':

https://www.paragon-software.com/home/hfs-windows/#

'Paragon HFS+ for Windows' is payware, but has a free 10-day trial,
which should be enough.

Paragon has also a product for APFS filesystems (see Paul's
responses).

According to my notes, I had more luck with 'Paragon HFS+ for
Windows'
than with 'HFSExplorer' (http://www.catacombae.org/hfsexplorer).

'HFSExplorer' is more limited/basic than 'Paragon HFS+ for Windows',
but it might be enough for your situation.

Good luck with your recovery efforts.

Hi,

Thanks to all that replied.

Frank, glad you were able to do what we have not been able to do, yet.

My daughter and I were finally able to get together, and I got more
information from her. First, I don't know why the motherboard was
deemed dead by the Apple geniuses, even though they said they did
'tests' on it, because it is not. And I don't know why my daughter was
not able to get the iMac to even sound like it was on, let alone show
anyting, even POST, on the screen. I suspect that the iMac may have
been plugged into a wall outlet that was not hot unless the wall switch
was on.

The iMac did turn on, but had the spinning circle of death. Some
readings say that this could be due to an upgrade in progress that was
aborted. My daughter doesn't remember. That was five years ago.

There are two parts to the story of what we accomplished/didn't
accomplish.

1) Now that the iMac is not completely dead, let's see what we can find
on the hard drive.

With the original hard drive put back in the machine, the iMac did turn
on, with the spinning circle of death. Well, at leasat there's
something going on. We found the iOS disc, and printed on the disc
itself it said to insert disc, power down, power up, 'press C' after
turning on power. This should bring up the disc utilities allowing you
to recover/install anew. Ok, let's try that.

This was a little more difficult than expected, because we found a
music cd was in the Super Drive. Of course we couldn't eject it,
because the iOS woundn't load. We had to remove the Super Drive, and
then use a putty knife to remove the music cd. Once out, we put the
Super Drive back in the machine, and inserted the iOS disc, and pressed
C on the Apple keyboard.

Oops, the original Apple keyboard (bluetooth) was unusable because
after five years of non-use, with the battery still in it, leaky
alkaline build up had cemented the battery compartment shut to the
point where heavy duty twisting with a large blade flat tip screwdriver
wouln't budget the battery compartment door one mm. I had plenty of
extra USB keyboards, which we tried, but none worked. Down to BestBuy
to get a cheap USB keyboard that was Apple compatible. BestBuy's
in-house brand, Insigna for $20, worked.

Pressing the C key while the machine was booting did bring up the disk
utilities most of the time. When it did, we went as far into it as we
could to explore the menus without going the the point of no return.
But, the menus that appeared were not what the instructions said would
appear. We backed out because we wanted to try to move/copy the
pictures/videos from the drive more that recover/reinstall, which could
wipe out the files we wanted to move/copy.

2) So much for trying to read the hard drive while installed in the
machine. Let's see about moving/copying files from the original hard
drive to my daughter's HP laptop.

We removed the Apple hard drive and installed HFS+ along with Java, on
my daughgter's HP Win10 laptop, and connected it to the laptop, and we
could intermittently access the hard drive. The hard drive did show up
in disk manager, but not in Windows Explorer. We did not expect it to
show up in any Windows window. It did show up in HFS Explorer, but
when we tried to extract a file, we'd get a few files extracted to the
HP, but then a Java error would appear, and the process halted. We
were never able to move/copy more than a few files. Here's the error
message:

https://postimg.cc/image/l2d72vcnf/

Next, I loaded Paragon's HFS+ for Windows on to my Win7 desktop, and
connected the Apple hard drive. This time, the Apple hard drive would
not show up anywhere, and Paragon gave me this message:

https://postimg.cc/image/l3n4w946j/

But see where it says 'restart the service'? If I pressed that link,
I'd get connected to the iMac hard drive:

https://postimg.cc/gallery/g75huiu4/

(Ignore file names, for some reason file names didn't carry over to
postimg correctly)

If I pressed the Close button on the Macintosh HD screen, I was sent
back to 'restart service'.

I will try some more later this week.

Thanks for reading this far.
To get past the I/O error, you could try gddrescue from a
Linux LiveCD.

OK. So I went off and did some reading, since I've never done anything
with Linux, but have always been curious. I'd like to try and see how far
I can get. If I don't get far, because this is beyond my skills, or if I
am able to complete this process but the Apple drive is too far corrupted,
I will have at least learned a little about Linux, and may experiment with
a LinuxLive distribution on a spare pc.

Let me see if I understand the first few steps of the mechanics of the
process.

Download (obviously from a working pc) a LinuxLiveCD iso, and create a
bootable set of LinuxLive cds. Possibly from he
https://cdimage.debian.org/debian-cd...64/iso-hybrid/

Connect both the error ridden Apple 500GB hard drive, and another hard
drive with at least 500GB of free space to a working pc (this Win7x64
machine)

Boot the Win7 using the LinuxLiveCD
Once in Linux, run the command:
sudo gddrescue if=/dev/sda of=/dev/sdb

If the above is correct so far, will there be on-screen directions as to
where to direct the retrieved sectors?

The Linuz LiveDVD is about 1.5GB in size and a single-layer
DVD should be sufficient to hold it. You can also use a
USB stick if the disc is known to be a hybrid equipped
with USB boot. It takes a sector-by-sector dd (disk dump)
copy to make a USB stick.

Making the DVD is a bit easier, if you're more familiar with
converting ISO9660 to bootable media.

When the LiveDVD is booted, you need to find a Terminal
to issue the command. In Ubuntu, you use the dash icon,
which is top or bottom left, and type the name of the
command you want ("Terminal").

*******

This is the first example I found. gddrescue is the package
name of ddrescue on some platforms (like maybe Ubuntu or Mint).

http://www.cgsecurity.org/wiki/Damaged_Hard_Disk

man ddrescue

# first, grab most of the error-free areas in a hurry:
sudo ddrescue -n /dev/old_disk /dev/new_disk rescued.log
# then try to recover as much of the dicey areas as possible:
sudo ddrescue -r 1 /dev/old_disk /dev/new_disk rescued.log

In this example, a disk is being transferred to an image file,
rather than to another disk.

-b8M max block size 8MB per transfer, auto-adjusts itself
/dev/sdb source disk
sdb.raw destination image file
sdb.log text file keeps track of progress
-S sparse (only helps if disk was whitened with zeros first, optional)

sudo ddrescue -S -b8M /dev/sdb /mount/external/backup/sdb.raw /mount/external/backup/sdb.log

I've checked my records and I don't seem to have a worked example.
I think the problem was, the example with the -S in it,
all the sectors were collected on the first pass, so there
was no need to do a second pass. If a second pass was
attempted, it would have exited in a microsecond, because
there was no work to do.

You can use

ddrescue

to get the OS to tell you how to install it. Perhaps

sudo apt install gddrescue

is what it answers, as the command to use.

Then

man ddrescue

for the options.

The first major argument is the source (/dev/sdX)

The second argument can be a disk when cloning (/dev/sdY)
or if you have a formatted partition just sitting
there which is 500GB in size, you can dump to
sdb.raw on that partition. That's how you'd make
a backup image.

The disk dump command (dd), which is available on
more platforms, is less polished. It uses if=
for the source disk. It uses of= for the destination disk.

My problem here, is I don't have any disks throwing an
I/O error, to use for making sample runs. I have good
disks or dead disks, and nothing useful for this sort
of work.

Using the manual page, you should be able to figure it out.

The important thing is, the package name is gddrescue,
while the executable is ddrescue, and the "sudo" thing
means to elevate to root user so that physical address
to the disk is possible.

There are backup softwares which promise to do this
sort of thing, but... I don't trust them. One test
showed the maker lied about their capabilities. At
least with gddrescue, I know it does what it says
on the tin. The format they use for the .log file,
shows they thought about how to do this a bit.
This wasn't a ten minute software development effort.

Paul