I need a program that functions like HDD Regenerator, eg: to restore a
quick formatted partition. DOS and HDD Regenerator won't work with a
usb to ide disk adapter. GetDataBack and the like only want to restore
data to other drives, not restore the same drive.
I don't use HDD Regenerator, but the following product does not appear
to "restore a quick formatted partition". Instead its author claims it
will repair "physical bad sectors". <shrug>
HDD Regenerator 1.61:
http://www.dposoft.net/#b_hddhid
Program features
Ability to detect physical bad sectors on a hard disk drive surface.
Ability to repair physical bad sectors (magnetic errors) on a hard
disk surface.
The product ignores file system, scans disk at physical level. It can
be used with FAT, NTFS or any other file system, and also with
unformatted or unpartitioned disks.
How it works
Almost 60% of all hard drives damaged with bad sectors have an
incorrectly magnetized disk surface. We have developed an algorithm
which is used to repair damaged disk surfaces.
This technology is
hardware independent, it supports many types of hard drives and
repairs damage that even low-level disk formatting cannot repair.
Almost 60% of all hard drives damaged with bad sectors have an
incorrectly magnetized disk surface. We have developed an algorithm
which is used to repair damaged disk surfaces. This technology is
hardware independent, it supports many types of hard drives and
repairs damage that even low-level disk formatting cannot repair.
- Franc Zabkar
You can't physically repair a damaged disk surface, it is
in a sealed unit.
From following this group I've found that spinrite is absolute rubbish,
and now hdd regenerator is rubbish too?
I've tried to debate with the spinrite developers on news.grc.com using
some of the arguments against it from this newsgroup, but it never goes
anywhere, so I gave up:
http://12078.net/grcnews/article.php?id=12230&group=grc.spinrite.dev#
12230
From following this group I've found that spinrite is absolute rubbish,
and now hdd regenerator is rubbish too?
I believe that Steve Gibson makes some bogus claims (eg that magnetic
domains weaken over time), but the basic methodology behind Spinrite
seems logical to me.
By that I mean that Spinrite will turn off ECC and try to read a bad
sector up to 2000 times.
If at the end it doesn't achieve an error
free read, then it will try to reconstruct the sector based on the
most probable value of each bit.
OTOH, the author of HDD Regenerator claims that he uses an undisclosed
algorithm which is hardware independent. This would mean that he is
limited to whatever ATA commands are available to him via the ATA
spec, as is Steve Gibson. It seems to me that the easiest "hardware
independent" solution would be to read the bad sector up to 2000 times
and give SMART a chance to reallocate it.
The Sstrength of the SpinRite description is that it did
make sense for older HDD technology. It does not anymore today.
One thing is that the on-disk encoduing used to be standardized
in the MFM/RLL days and the ECC was standard as well. This is not
true anymore today, and reading with ECC off does not make any
sense.
There are some claims on Steve Gibson's web site which I don't
understand.
Just because ATA-4 retired it doesn't mean it is no longer implemented.
The original 4-byte ECC is long gone, but I recall an IBM manual
describing another bit (when set) will read the full ECC (400 bits or so).
Steve Gibson claims to be able to influence a HD's read AGC (automatic
gain control) circuit.
SpinRite's Defect Detection Magnetodynamics:
http://www.grc.com/srphysics.htm
He says that ..
"SpinRite is actually able to lower the amplification of the drive's
internal read-amplifier, then to cause the drive to encounter a
'minimum amplitude' data signal. If that data signal happened to fall
upon a spot of the drive's recording surface that is in any way 'weak'
then the drive will mis-read the data bit and return an error for the
sector containing the bad spot."
However US patent #6839193, entitled "Method and apparatus for
determining read-to-write head offset of a disk drive", assigned to
Seagate, shows that the data field of each sector is preceded by an
"AGC data field which may be used to set read sensitivity".
The patent states that "when the read/write head is over the AGC data
field the gain of the recovered signal is adjusted to provide a
predetermined constant amplitude signal in order to reduce
demodulation errors."
So it appears to me that the read amp's AGC circuit is "trained"
during the "preamble" to the data field and is therefore not
influenced by the data pattern. Of course I'm assuming that the
technology described in the above patent (dated Jan 4, 2005) is
actually being implemented in current products.
If I remember correctly, that claim was bogus to begin with.
What he could do with MFM/RLL is to test with a pattern, that
was more sensitve to surface problems, as it used the weak spots
of the modulation. Pretty much like black magic, so he possibly
dumbed it down. The actuall read amplifier gain is not accessible
and was not accessible in the MFM/RLL times as well.
No idea.
Arno
Franc Zabkar said:On 31 Mar 2009 13:12:10 GMT, Arno <[email protected]> put finger to
keyboard and composed:
AIUI, Steve Gibson does not claim to be able to control the read amp
gain directly. AGC relies on a rolling average, so Gibson "trains" the
read amp with strong signals, causing the AGC to reduce the gain, and
then he feeds the amp with weak signals while the gain is still low.
As for whether AGC was used in the early MFM days, I have a circuit
diagram for the 20MB drive that was used in the original IBM PC/AT.
The read amp appears to consist of two-stage differential op-amps with
fixed gains, ie no AGC. The print is hard to read, but the op-amps
look like NE592 video amps which are also specified for use as floppy
disc head amplifiers.
AIUI, the above patent talks about an AGC data field that is used to
train the servo amp so that it can accurately position the MR read
head. If a write is commanded, then the servo is jogged slightly
off-track to where the write coil is known to be. This may partly
explain why the seek time for writes is slightly greater than for
reads. Accurate positioning is dependent on accurate calibration of
the servo signal. For example, if an on-track read signal, after AGC,
is 10mV, then the write head's offset from the read head could be
where this signal drops to 8mV, say. AIUI these read-write head
offsets are calibrated at the factory and vary from track to track.
In addition to the above AGC data field, it appears that the user data
field has its own preamble of "training" bits which are laid down when
the data are written. In this case these training and sync bits are
used to condition the read amp when reading back the user data.
According to US patent number 6055118, entitled "holding automatic
gain control levels during read error recovery in a disc drive",
assigned to Seagate, the data block begins with a phase locked
oscillator (PLO) field which provides timing and amplitude information
for AGC and clocking. This is following by a training field and sync
field, the latter being used to identify the beginning of the user
data. The patent states that "the AGC first operates in an
'acquisition' mode during which large adjustments in the gain are made
in response to the initial signal levels provided by the preamp to
provide a coarse adjustment of the gain. The AGC then transitions into
a 'fine adjustment' mode, during which the AGC normally continues to
provide small, incremental adjustments to the gain as long as the read
channel is enabled as a particular sector is read".
So at first it appears that SpinRite may be able to influence the AGC
as claimed by Gibson. But then the patent goes on to describe what
happens when a read error is encountered. In this case the drive
re-reads the previous sector on the same track, and determines its
appropriate gain based on its PLO field. It then retries the bad
sector by turning off AGC and applying the *constant* gain derived
from the previous good sector. So it seems that any error that is a
consequence of an attempt to confuse AGC will be automatically
corrected by the drive on its second try, by *disabling* AGC.
BTW, the second patent applies to drives using PRML signal processing.
From following this group I've found that spinrite is absolute rubbish,
and now hdd regenerator is rubbish too?
I've tried to debate with the spinrite developers on news.grc.com using
some of the arguments against it from this newsgroup, but it never goes
anywhere, so I gave up:
I find that interesting because I have a 13G IDE hard disk that gave
read/write errors only on the top 3Gs. Scandisk showed seemingly
random bad sectors but Spinwrite did not find any problems.
Back in the AT days I had a full height 20MB MFM hard drive
that would show several bad sectors which Spinwrite would
fix until they showed up again maybe 3 months later.
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