Windows based hard drive scan tool

  • Thread starter Thread starter JW
  • Start date Start date
Man-wai Chang said:
Yep.

So the drive was trying to remap the sector?
Click to expand...

Nope. Since the OS level bad check is JUST a read, the drive wont remap
on reads, because that will lose any data in that sector. The drive will only
remap a bad on a write to that sector, because it knows that the data doesnt
need to be got out of the bad. The bad is left on just a read so the user can
use a tool that aggressively attempts to get the data out of a marginal bad
when they dont have a proper backup for the data in that bad.
 
Oh my cow.. the device should let me choose how to deal with potentially bad sectors!!!!!
Click to expand...

It does, thats why it doesnt remap sectors on reads, so you
can do whatever you like retrying on the sector to see if you
can get the data back before it gets mapped away on a write.
Ask me about the number of retries....
Click to expand...

That wont work when the bad shows up when the system isnt attended.
With all these stupid attempts to save a bad sector,
Click to expand...

They arent stupid, they are crucial if you dont have a backup of the sector.
it meant we should just throw away the disk once you heard the VERY FIRST retry sound (click...click...click).
Click to expand...

Nope, because that can be due to other reasons than the drive going bad,
most obviously when its got too hot because the cooling has failed etc.

With those, the sectors will usually become readable again when the drive cools down.

You have quite a bit of control over how the drive behaves with the SMART system.
Like I said, OS level marking of bads is a hangover from the days before there was the
SMART system which give you a lot more control over how the drive behaves on bads
and even with the much more basic control that means that bads only get remapped
on writes, not reads.
 
GMAN wrote
I am mad that its not easy to move the G-list over to the P-list with SMART.
Click to expand...

Thats left for the hard drive manufacturer's ute to do if the manufacturer chooses to support that.

Some do.

SMART cant do it because the detail of how those lists are stored varys with the drive technology.
 
GMAN wrote


Thats left for the hard drive manufacturer's ute to do if the manufacturer
chooses to support that.

Some do.

SMART cant do it because the detail of how those lists are stored varys with
the drive technology.
Click to expand...
Exactly my point. I should be able to determine the fitness of whether to keep
risking and using the drive and not some built in "feature" that determines
the drive is no longer healthy enough to use due to some % algorithm.

Example, I have a seagate 750GB drive that due to the drive remapping 7 bad
sectors over its short lifespan into the g-list, the program i use to read
and track the health, Hard Disk Sentinel 3.30 Pro states that the drive is
down to 40% health. WTF??? over just 7 bad sectors? They were remapped
properly and none have grown since a year ago. But when and if the health
drops even just slightly more, SMART will then report to the motherboards bios
and all other tracking apps that it needs to be replaced and is bad.

I agree, to make it uber easy for anyone to fudge with the P-List and G-List
is a bad idea due to the risks, but it should be available to those with the
knowhow to be able to access with some program like HDAT2 or other utilities.
 
Oh my cow.. the device should let me choose how to deal with potentially
bad sectors!!!!!
Click to expand...

Emphatically not. That would expose hardware details that you
cannot fully understand. Or do you happen to be an expert
at this particular surface coating, head assembly and read
amplifier?
Ask me about the number of retries.... With all these
stupid attempts to save a bad sector, it meant we should just throw away
the disk once you heard the VERY FIRST retry sound (click...click...click).
Click to expand...

That would be stupid. If that is your standard, you cannot buy
any consumer drives.

Arno
 
Ed Light said:
On 10/24/2010 7:53 PM, Arno wrote:
Click to expand...
Ulp ... Arno, you're sounding like a bum we filtered out.
Click to expand...

Wups. Maybe formulated to strongly, sorry.

The thing here is I can understand wanting to do your own
defect management, but HDD technology has really moved so
far beyond that, it does not make sense anymnore.

The thing with consumer drives is that a whole lot of reads
do actually fail and only succeed because of error correction.
In a traditional HDD that would indicate a surface defect.
In modern HDDs it does not (or not in most cases). The nice
thing is that in most situations you get exposed defective
sectors only if the drive is dying. The negative thing is
that sometimes you still get read errors, but the disk and
sector read is fine.

So the read error, which used to have the semantics of new
"surface defect found", does today mean one of several things,
namely

1) Transient write error, e.g. due to environmental influence
2) Permanent write error (surface defect)
3) Permanent read error, i.e. disk is dying

with 1) being the most likely. Distinguishing between them
is really hard from the user side and 1) and 2) are best
taken care of by the disk, which is perfectly capable of
doing so. 3) can best be recognized by looking at the
critical SMART attributes.

Also note that in cases 1) and 2) you may get the characteristic
"sound" and the disk is still perfectly fine.

Anyways, manual defect management does not make sense in any
of these cases. Its time hass passed and it is obsolete for
HDDs. Ther are other areas where it is still needed.

Arno
 
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