read past dud blocks (on hard disc)?

  • Thread starter J. P. Gilliver (John)
  • Start date

J

J. P. Gilliver (John)

Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

A few things - like IrfanView - will read _up to_ the dud block, and
give you the first part, filling the rest with grey; most things, such
as Windows Explorer, just read up to the dud block, then pause for ages,
then give you an error message without giving _any_ of the corrupted file.

I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.
 
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P

philo 

Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

A few things - like IrfanView - will read _up to_ the dud block, and
give you the first part, filling the rest with grey; most things, such
as Windows Explorer, just read up to the dud block, then pause for ages,
then give you an error message without giving _any_ of the corrupted file.

I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.






I've used one of the disk utilities on a Hiren's CD to "repair" faulty
hard drives. http://drevitalize.soft32.com/ will attempt to write the
data off a bad block, then mark it out.

It will take a while, but it will be considerably faster than SpinRite
which could take a week or so.
 
B

B00ze/Empire

Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

[snip]
I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.

Ok, so what I'm about to suggest doesn't pass the Free GUI test, but its
worked for me before: GHOST the partition, then you can use GhostDisk to
retrieve whatever files you want, and bad blocks are zeroed. Perhaps one
of the free imaging tools can do the same (Macrium? Paul?)

Best Regards,
 
B

Big_Al

Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

[snip]
I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.

Ok, so what I'm about to suggest doesn't pass the Free GUI test, but its
worked for me before: GHOST the partition, then you can use GhostDisk to
retrieve whatever files you want, and bad blocks are zeroed. Perhaps one
of the free imaging tools can do the same (Macrium? Paul?)

Best Regards,

What's 'Paul'? Just curious, I thought I'd seen most of them.
 
P

Paul

J. P. Gilliver (John) said:
Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

A few things - like IrfanView - will read _up to_ the dud block, and
give you the first part, filling the rest with grey; most things, such
as Windows Explorer, just read up to the dud block, then pause for ages,
then give you an error message without giving _any_ of the corrupted file.

I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.

See "ddrescue" near the bottom of this article.

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

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

It's a two-pass disk copier. It copies from the bad
disk to a good disk. It skips sectors it is having
trouble with, on the first pass. And fills in sectors on
subsequent passes. I presume rescued.log records progress,
as to what has been recovered.

You'll need a platform to run it on. It's not a Windows
program.

Macrium or a number of other backup/clone programs
wouldn't be the best choice, because they're not designed
to intelligently handle bad sectors. Some backup programs
do a disk integrity check (equiv of CHKDSK) before they
do anything, and so they'd stop before they even
got started.

Paul
 
J

J. P. Gilliver (John)

Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?
[]
Thanks those who have replied, especially philo and Paul.

Maybe I didn't make it clear that I've given up on the lost sectors.

I think _most_ of the corrupt files (there aren't that many) _aren't_
fragmented, so the bad blocks should be in the middle of fragments. I've
run the dud drive through HDDscan, and virtually all the bad blocks are
isolated from each other rather than contiguous.

What I'd really like is something that will copy a file on the dud disc
like this

dddddddddXddd

to this on the good disc

ddddddddd0ddd

from within Windows, without having to worry about blocks, sectors, or
anything else (where d is a good data block, X an unreadable one, and 0
just padding to replace the unreadable block; OK, if it can include some
of the lost block all the better).
 
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J

J. P. Gilliver (John)

On 10/06/2014 08:42 PM, B00ze/Empire wrote: []
retrieve whatever files you want, and bad blocks are zeroed. Perhaps one
of the free imaging tools can do the same (Macrium? Paul?)

Best Regards,

What's 'Paul'? Just curious, I thought I'd seen most of them.
Paul is excellent AI software, that often posts useful posts here .. (-:
 
P

Paul

J. P. Gilliver (John) said:
Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?
[]
Thanks those who have replied, especially philo and Paul.

Maybe I didn't make it clear that I've given up on the lost sectors.

I think _most_ of the corrupt files (there aren't that many) _aren't_
fragmented, so the bad blocks should be in the middle of fragments. I've
run the dud drive through HDDscan, and virtually all the bad blocks are
isolated from each other rather than contiguous.

What I'd really like is something that will copy a file on the dud disc
like this

dddddddddXddd

to this on the good disc

ddddddddd0ddd

from within Windows, without having to worry about blocks, sectors, or
anything else (where d is a good data block, X an unreadable one, and 0
just padding to replace the unreadable block; OK, if it can include some
of the lost block all the better).

The basic idea is:

1) Do the ddrescue, as best you can. Do multiple passes until
only a few unreadable sectors remain. Copy from the bad drive
to the good drive. The good drive should be the same size or
larger than the bad drive.
2) The unreadable sectors should be rendered as zeros. You can
zero the entire destination drive, if that is not the case
(I haven't checked the ddrescue code, to see whether it fills
the destination on the first pass or not). A regular copy of
"dd.exe" can use /dev/zero as a source of zeros, to zero out
a disk drive.
3) When you've finished your best effort to copy the disk,
now you can use CHKDSK, or try to copy the files from the
destination disk. So from now on, you work with the destination
drive in hand. As no operation on it, is going to time out like
it would on the bad disk.

The reason for doing this, is so the 15 second per sector timeout
won't hold up the file copy or CHKDSK repair attempts.

I don't know of a tool that combines bad block scraping with
file copying. There's probably something out there, as there
are a ton of $39.95 recovery programs. Some of them, you download
and test, and they tell you what files they think they can recover.
When you pay them the $39.95, they give you a license key, and then
you get to find out whether the recovery really works.

If the bad blocks are in the $MFT, things could get messy.

I used to have a link to a free recovery package, but it looks
like the link is no longer valid. Leaving the $39.95 stuff.

If you just try to copy a particular file, and it's in the middle
of a bad section, then you'll be paying 15 seconds to find each
bad sector. Operations will then take forever. Presumably ddrescue
does a bit of "back and forth", to try to find areas suited to
capture. And do a better job of reducing the unrecoverable list,
as quickly as possible.

The free recovery program was "driverescue19d.zip" 1,007,764 bytes.

Paul
 
B

B00ze/Empire

Ok, so what I'm about to suggest doesn't pass the Free GUI test, but its
worked for me before: GHOST the partition, then you can use GhostDisk to
retrieve whatever files you want, and bad blocks are zeroed. Perhaps one
of the free imaging tools can do the same (Macrium? Paul?)

Oops, I meant go grab the files from the ghosted image using
GhostExplorer, not GhostDisk. Btw, this worked for me with old DOS
Ghost; it might not work at all with newer Ghost's that run under Windows...
 
B

B00ze/Empire

It's a two-pass disk copier. It copies from the bad
disk to a good disk. It skips sectors it is having
trouble with, on the first pass. And fills in sectors on
subsequent passes. I presume rescued.log records progress,
as to what has been recovered.

Thanks for the research. I read the ReadME and the webpage, it LOOKS
like ddRescue is able to process files (rather than copy an entire disk)
but there's no MAN and I dont have a Knopix CD handy to try it out, so I
can't be sure it supports file by file (this would be the simplest).
Still, looks like it does what the OP needs.

Best Regards,
 
P

Paul

B00ze/Empire said:
Thanks for the research. I read the ReadME and the webpage, it LOOKS
like ddRescue is able to process files (rather than copy an entire disk)
but there's no MAN and I dont have a Knopix CD handy to try it out, so I
can't be sure it supports file by file (this would be the simplest).
Still, looks like it does what the OP needs.

Best Regards,

That's a good idea. To test whether it can do file copies.
Maybe it can, and still fill the log while doing so. That
will save John some time.

*******

The "dd" family of tools, can copy disks

dd if=/dev/sda of=/dev/sdb

but it can also copy files (contents copied from
one disk to another).

dd if=C:\dog.txt of=D:\cat.txt

It could also be used to image a hard drive and
store it as a (very large) file.

dd if=/dev/sda of=D:\wholedrive.dd

So the ddrescue should also support the same sorts
of options. All the while, keeping track with its log
file. So there is a good possibility you can avoid
a lot of unnecessary copying.

However, if the $MFT on NTFS is part of the damaged
stuff, you might not get a logically consistent
file in a quick copy. Then, copying the whole
disk and running CHKDSK on the destination drive,
might be needed.

*******

There is a port of the vanilla "dd.exe" program here.
But this one would not like bad sector handling at all.
And is not a replacement for ddrescue. This runs in
Windows command prompt, and I've used it a fair bit.

http://www.chrysocome.net/downloads/dd-0.6beta3.zip

The "ddrescue", you're likely going to need to
run that from Linux.

I don't see a ddrescue here.

http://gnuwin32.sourceforge.net/packages.html

And the other possibility, would be a Cygwin port.

http://cygwin.com/packages/x86/ddrescue/

It's listed there. So perhaps you can run it from
Windows via Cygwin. What I find with some of these "ports",
is they use Linux disk identifiers, and don't
switch them to Windows identifiers. And then the
program fails miserably. So just because a tool
is listed in one of these environments, doesn't
mean someone actually paid attention to what
is in the code. I ran some NTFSPROGS stuff
a while back, and it was using Linux identifiers
and could not do what I wanted.

HTH,
Paul
 
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M

Mike Tomlinson

J. P. Gilliver (John) said:
What I'd really like is something that will copy a file on the dud disc
like this

dddddddddXddd

to this on the good disc

ddddddddd0ddd

dd_rescue will do exactly this (note there's ddrescue and dd_rescue, the
latter is the one you need)
from within Windows

Unfortunately not.

To use dd_rescue, you'll have to use a Linux live CD and the command
line. It may run under Cygwin, but personally I would use a live CD.

http://www.garloff.de/kurt/linux/ddrescue/
 
J

J. P. Gilliver (John)

(Long ...)
[]
"J. P. Gilliver (John)" wrote in message
Is there anything that will read a file with a dud block (on the hard
disc) in it, replacing the dud block with zeroes, ones, or something?

I don't mean something like SpinRite, that tries to reread the dud block
up to 2000 times in the hope one of them will succeed; I just mean
something that'll copy _past_ the unreadable block.

A few things - like IrfanView - will read _up to_ the dud block, and
give you the first part, filling the rest with grey; most things, such
as Windows Explorer, just read up to the dud block, then pause for ages,
then give you an error message without giving _any_ of the corrupted file.

I have a few videos I'd like to recover from the dud disc - with maybe a
few dropped frames.

Ideally something free and GUI, rather than paid or command line: I just
want, ideally, to be able to drag the corrupted file to a new location,
and get a file (with some dud blocks) that at least can be read without
lockup-and-loss.

Just thought I'd give you all a summary.

I did have: Samsung NC-20 netbook (a 12" one, so the keyboard has almost
full-size keys), with a (Samsung) 160G drive in it (as originally
supplied). XP, my main machine.

Acer Aspire 9301, 7HP. (17".) Bought _mainly_ to support (including
several blind) friends who have 7, but also to get more familiar with 7,
and also to have the power for when I need it (it's a much more modern
PC). [320G drive.] (I rarely do need it: I'm not a gamer, or even much
of a video watcher. Mainly email, usenet, and genealogy.)

I'd always backed up important data to a second partition on the HD,
since in the past my experience in the past has always been that HDs
give some indication of impending failure, at least long enough to copy
data off. However, I always "meant to" get a physical backup drive, not
only to back up to a truly separate drive, but also to use one of the
things we discuss here occasionally - Acronis, Macrium, etc. - to back
up the _system_ area so I can restore my XP system if I need to. (The
intricacies of how XP OEM [the netbook came with XP SP3 preinstalled]
validates/authorises itself having been something I've never really been
that interested in learning.)

Then - the _day_ before I was due to go to a computer fair at which I
was going to buy my backup drive (actually probably only a few hours
before; I play late), the drive on the netbook stopped - suddenly, with
no warning.

I went to the fair anyway, and bought a couple of drives (a 1TB 3.5"
purely for backup, and a 250G 2.5" for the netbook). Both with 3 year
guarantees - one can't be sure of anything these days, but I thought
that was my best bet. (If anyone's interested, the 1T is a Seagate and
the 250G is a Hitachi.) (I also bought an external dock - red and black
thing, does SATA and PATA [and USB, and card slots ...]: the quite
meaty-looking "3A" 12 power supply it came with died after a few days,
though fortunately I have another one that's serving. A friend tells me
he's seen on t'internet that the PSUs with these docks are commonly
failing, in one case fierily so. I'll take it back next time I go to the
same fair.)

During the next few days, I tried the various methods on the internet
for recovering a dead drive, including the freezer. I could tell (hear)
it wasn't rotating. (Actually consensus is that the freezing is _not_ a
good idea because of condensation on the platters causing head crashes
and damage when it does spin up, and I think there may be _some_
validity to that - it wasn't important in my case as it _didn't_ spin
up. My trust in the people who warn about condensation wasn't boosted by
one of them - on YouTube - _showing_ the condensation; obviously, to do
so, he'd opened it up and exposed it to the air. Others claim that this
isn't too relevant as they're not actually hermetically sealed anyway;
OK, and yes mine has a breather hole, but I'm still not sure that's the
same as actually opening it up when its cold.) Another suggestion I
found on the 'net was that the overvoltage protection diodes sometimes
fail _short_ circuit and thus prevent power reaching the drive (or part
thereof); this seems unlikely to me (such diodes usually IME - and I
work in avionics, and one of the units I service is always coming in
with them blown - fail _open_ circuit), but lots of people said it had
worked for them, so I disconnected it (at one end): no change. (I
haven't got round to reconnecting it.)

Even considered using a data recovery service. But I had concerns about
whether they'd keep copies of what was on the drive; however reputable
the company, it only takes one employee ... In practice I'm glad I
didn't, as I don't think they'd have done _much_ better than I did in
the end.

So, eventually, I bit the bullet, and - in our company clean-air cabinet
(incidentally: such cabinets, and clean rooms, operate under _positive_
pressure, not what you'd intuitively think), after running its fans for
a while - I opened up the drive. (A Torx #6 'driver fitted the seven
screws; note there's one under one of the labels, but unlike some of
those on YouTube, I didn't poke through the label, but was able to
carefully peel it back, and replace it afterwards.) I found the head on
the drive, not parked to the side as it should have been. I very
carefully turned the drive - using the driver; the same one fitted the
hub. I felt slight resistance; the head(s?) had indeed obviously stuck
to the drive. I carefully (without touching the platter surfaces) moved
the head assembly back to its park position, reassembled, took it over
to my dock, and tried power - whee, it span up. Rushed home to extract
as much as possible before the doom set in predicted by all those on the
net who said never open a drive. (To be honest, I suspect that - for the
short time involved, at least - opening in a normal home, as long as
there are no smokers or similar - you'd get away with it anyway;
especially if you made your own clean cabinet with a fan and some
filters [positive pressure, remember]. But don't quote me on that!)

Anyway, I got home, and set to _moving_ - not copying - from the two
partitions, to a couple of folders (called something like C-saved and
D-saved) on the other laptop. (Couldn't use the dock to copy straight to
the new backup drive: it only has one SATA slot!) Now, before you all
suck in breath at my doing a move rather than a copy: I'd tentatively
looked first, and saw that the drive appeared to be mostly OK. Doing a
move meant that I could _easily_ see what hadn't copied.

During subsequent days I tried to recover the few files that didn't come
off the first time. I think I might have recovered one or two.

When I'd _more or less_ given up (I still have the dud drive), I
Macriumed an image of the recovery partition (100M, IIRR) and the C:
(about 30G). This was mainly to give myself the best chance of getting a
valid XP system back.

I then put the new (250G) drive into the dock. First, I restored from
the image, so that the recovery partition and boot parts of C: were
"restored". I then resized C: to 40G, made a D: partition for the rest
(I still intend to keep most of my data away from C:, to [a] keep the
image size down, keep _data_ backing up something I can do with
plain copying), and then moved files from the two directories on the 7
laptop back to the two partitions.

(I spent a few more days trying again to get the few dud files back.
Without success.)

A couple of days ago, I finally bit the bullet again, put the new drive
into the netbook, and powered it up. Something Samsung came up: it
offered me at least two options, one which was a minimum restore (or
repair or something), one a full (or something like that) which it said
would erase everything. Obviously, I chose the first one. After a little
while, my system is back!

After a very few more repairs, obviously first thing done has been make
a new Macrium image - now of the hidden partition and the (resized and)
reloaded C: - and a copy of D:, this time onto the new backup drive.
(I'd made - and used - the Macrium boot CDs [two, one for 32 bit and one
for 64; not sure whether I needed both, but I got the impression I did];
incidentally, they fit onto mini-CDs.)

So all is well, and I'm back typing on the netbook. (The 17" one is a
bit heavy on the knees!) [It's _so_ nice to be back using the software
I'm used to (which won't run under 64-bit), not to mention have all my
back emails/news for many years!]

The one remaining thing I'd _like_ to do is get back the remaining dud
files: in particular a few videos I'd taken, which would probably just
show a glitch for the corrupted sectors. I've kept several of your
suggestions in this thread, and may pursue some of them at some time in
the future, when I feel up to doing battle with Linux and/or command
line. I must say I've completely given up any hope of reading the bad
sectors, so please _don't_ suggest anything for that; however, if anyone
does know of a free, and Windows (XP or 7), utility that will read a
FILE that has a few (I suspect only one for most of my files),
zero-filling (or whatever) where the dud bits are, I'd be very grateful.

(In the distant past, under BBC BASIC in the days of floppy discs, I
even wrote something: it read a byte at a time, wrote it to another
file, and closed the other file in the event of an error. That at least
gave me files up to the dud, though not the bit after.)

When I look at the dud disc in Windows explorer (under 7 at least), and
look at a folder with images or videos in, it shows me thumbnails for
most of them, which is at least partly why I suspect they're mostly
single sector faults. I also scanned the whole drive with HDDScan, which
gives a nice graphical picture as it goes, and didn't see _any_ adjacent
bad blocks, only single ones (though I could have missed a _few_ - it
did take some hours!). For interest, HDDScan gave the following totals
(access times):
< 5 ms 112703 sectors
<10 ms 1058776 (probably would have been <5 if not for USB, multi, &c.)
<20 ms 7049
<50 ms 18991
<150 ms 11378
<500 ms 4781
500 ms 2048
Bads 5297

I presume the Bads (less than half a percent, though obviously enough to
consider the drive scrap) are from where the head(s) stuck to it, plus
_possibly_ - though I was careful [and this is where I think a data
recovery company could _possibly_ have bettered] - from my moving them
back to the park area. (They were about half way across the disc; do
modern discs start from the middle or the edge?)

Oh, and a final thought/question: what caused them to stick? Also, I've
just checked my Power Options: I'd thought maybe I should change from
turn off hard discs to Never, but I see I already have it set to Never
anyway when on external power, which it was when it died (I thought
maybe I'd got them set to power down). So it seems they must have stuck
while spinning (which, on reflection, means I was lucky there wasn't
_more_ damage). I'm pretty sure they were stuck: initially after failure
when power was applied there was a little tinkling, which a friend
thinks was the heads trying to move, and when I eventually opened it and
turned the spindle, I _think_ I felt a definite "unsticking".
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)[email protected]+H+Sh0!:`)DNAf

I would have suffered a hell of a
lot more if I had been understood. -Clarence Darrow, lawyer and author
(1857-1938)
%%
I hope you dream a pig.
%
 
K

Ken Blake, MVP

I'd always backed up important data to a second partition on the HD,
since in the past my experience in the past has always been that HDs
give some indication of impending failure, at least long enough to copy
data off.


Glad to hear you got most of your data back. I won't comment on the
rest of your message, but I wanted to comment on the sentence above:

Perhaps you've learned your lesson. but I strongly recommend against
backup to a non-removable hard drive because it leaves you susceptible
to simultaneous loss of the original and backup to many of the most
common dangers: hardware failure, severe power glitches, nearby
lightning strikes, virus attacks, user error, even theft of the
computer.

And I would especially worry about theft of the computer with a
laptop.


In my view, secure backup needs to be on removable media, and not kept
in the computer. For really secure backup (needed, for example, if the
life of your business depends on your data) you should have multiple
generations of backup, and at least one of those generations should be
stored off-site.
 
M

Mike Tomlinson

En el artículo <[email protected]>, J. P. Gilliver
(John) <[email protected]> escribió:

Glad you got (most of) your data back, and thanks for the report. Can I
comment on the following:
During the next few days, I tried the various methods on the internet
for recovering a dead drive, including the freezer. I could tell (hear)
it wasn't rotating. (Actually consensus is that the freezing is _not_ a
good idea because of condensation on the platters causing head crashes
and damage when it does spin up

You're meant to put the drive in an airtight bag before stuffing it in
the freezer, which prevents condensation from forming. If you have any
of those dessicant silica gel packs, it would be an idea to pop a couple
in the bag as well.
Others claim that this
isn't too relevant as they're not actually hermetically sealed anyway;

They're not, they have a breather hole to equalise pressure with the
atmosphere (but read on).

There is air in the drive. it's required for the aerodynamic effect
that lifts the heads off the platter as they spin. Without this effect,
the heads would scrape the magnetic material off the platters.

The exception is the recently launched Helium-filled drives. For
obvious reasons, these have to be hermetically sealed as allowing air in
via a breather hole would also let the helium out :)
OK, and yes mine has a breather hole,

you should have found it has a micromesh filter on it to prevent
particles entering the drive. There may also be another internal filter
sited in the airflow created by the spinning platters.
I carefully (without touching the platter surfaces) moved
the head assembly back to its park position

I would have suggested not doing that. You probably scratched the
surface of the platter, since the heads were resting on it, and now
cannot read the data from the scratched areas. The best thing to do
would have been to reassemble and power the drive up. Once the platters
started to spin, the aerodynamic effect would have lifted the heads
clear of the platter surface.
(They were about half way across the disc; do
modern discs start from the middle or the edge?)

I believe it's from the edge. CDs and DVDs, conversely, start from the
centre.
Oh, and a final thought/question: what caused them to stick?

The heads are slightly concave, so that when they come to rest on the
platter a vacuum can develop and they become stuck. You were lucky you
didn't rip the heads off the arms when you turned the spindle by hand.

They are supposed to auto-park when the drive is powered down, clearly
that didn't happen in your case. You may have noticed that the park
position locates the heads on a wedge-shaped effort which lifts them up
from the platter. This is so that when the drive next spins up, the
heads are not resting on the platter surface, damaging it.
 
P

Paul

J. P. Gilliver (John) said:
Oh, and a final thought/question: what caused them to stick?

This article addresses some of the possible causes.

http://en.wikipedia.org/wiki/Stiction

At one time, drives used CSS or Contact Start/Stop. There
was no landing ramp, no place to elevate the heads from
the platter.

Your drive, at 160GB, should be using a landing ramp.
At that density, it needs a landing ramp and an FDB motor.

And there's really *no* good reason for the head
to be sitting out there. Some unexpected series
of conditions, conspired to leave it there.

Sure, if you have a cabinet or glove box, with
hepafilter cleaning the positive pressure air feeding
the box, you can open up a drive. What isn't
recommended, is opening the drive in your dusty
living room, with absolutely no advanced preparation.
Even if you take the drive into a cabinet, you should
clean the outside of it a bit first, before opening it
up.

Paul
 
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J

J. P. Gilliver (John)

I always figured that most of those were either sufficiently unlikely,
or that I'd have more to worry about (if, for example, my house had
burned down). But I had more or less decided to get (and, obviously,
use) an external, backup, drive anyway - but this happened less than a
day before I was due to do so!

Having now experienced it, I'm going to use it (I already have in fact)!
The part that represented the most work - my genealogy - already _was_
copied to my brother's computer (some hours' drive away, in another
county). Though the schedule was somewhat erratic, as it depended on
when I visited him.
Also, beware of accidentally deleting a file on the PC, without
realising, then performing a backup and that backup process deleting
the corresponding file from the backup. Or accidentally deleting a file
from the back up and the backup process deleting it from the source PC.

I am using a Macrium image for the hidden (recovery) partition and the
C: partition. I keep all my data on a D: partition: partly to keep down
the size of the image of C: etc. (and thus the time it takes to make it,
and thus the probability of my making it!), but also so I can do backups
of D: just by using copy - and get at any file in it without needing any
software beyond Windows Explorer. So no problems with automatic backup
software upsetting anything.
I use Microsoft SyncToy to backup my PC files to external USB drives,
and I have it set to Echo rather than Synchronise to avoid deleting
files from the backup if I accidentally delete them from the source.

I copy ... (-:
I'd advise always using file-for-file copying software so the backup is
an exact copy of the source, rather than something like MS Backup which
backs up everything into one huge proprietary file: not only do you

I've never liked "one huge proprietary file" for anything -
need the proprietary software to retrieve anything from the backup file
but also if anything corrupts that file, you may lose everything - or
at least everything beyond the point of the corruption.

- for exactly those reasons. Ideally, I'd use email/news software that
stores emails/posts as separate files, but there isn't anything common
that does so.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)[email protected]+H+Sh0!:`)DNAf

What's awful about weird views is not the views. It's the intolerance. If
someone wants to worship the Duke of Edinburgh or a pineapple, fine. But don't
kill me if I don't agree. - Tim Rice, Radio Times 15-21 October 2011.
 
W

...winston‫

J. P. Gilliver (John) said:
- for exactly those reasons. Ideally, I'd use email/news software that
stores emails/posts as separate files, but there isn't anything common
that does so.

In Windows, OE was the last free client by MSFT to store files(mail and
news) in database (dbx format). Outlook, MSFT's flagship Office
product, also stores mail messages in a database file (*.pst).

All free MSFT clients post OE all store each email message in a separate
single file (*.eml) - those clients are Windows Live Mail (all
versions), Windows Mail (Vista), Windows Mail (8.0, 8.1, 10TP). All of
these except Win8's client also store news messages as separate files
(*.nws)

Note: TheWin8 client does not provide nntp capability and (for mail)
only supports EAS and IMAP.
 
K

Ken Blake, MVP

I always figured that most of those were either sufficiently unlikely,


Unlikely? Yes. But it's like buying insurance--to protect yourself
against unlikely things occurring.

or that I'd have more to worry about (if, for example, my house had
burned down). But I had more or less decided to get (and, obviously,
use) an external, backup, drive anyway - but this happened less than a
day before I was due to do so!

Having now experienced it, I'm going to use it (I already have in fact)!

Good!
 
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J

J. P. Gilliver (John)

Oh, and a final thought/question: what caused them to stick?

This article addresses some of the possible causes.

http://en.wikipedia.org/wiki/Stiction[/QUOTE]

Thanks, I'll have a look. Certainly felt like stiction when I unstuck
it. I'm just puzzled how it could have happened when moving; IME,
stiction only happens to things that are not moving.
[]
And there's really *no* good reason for the head
to be sitting out there. Some unexpected series
of conditions, conspired to leave it there.

I think it stuck, somehow. The spindle certainly wasn't spinning until I
freed it.
Sure, if you have a cabinet or glove box, with
hepafilter cleaning the positive pressure air feeding
the box, you can open up a drive. What isn't
recommended, is opening the drive in your dusty
living room, with absolutely no advanced preparation.
Even if you take the drive into a cabinet, you should
clean the outside of it a bit first, before opening it
up.

Sounds good advice - and I hadn't thought of cleaning the outside.
Anyway, I seem to have been fairly lucky; less than half a per cent of
sectors were/are bad, and I think I got maybe more than that proportion
of files off (presumably due to some of the bad sectors being in unused
areas).
 

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