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More life from hard disk with bad sectors

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Anonymous
a b G Storage
July 26, 2004 4:35:14 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Hi All

One of my hard disks continued to develop bad sectors and every time I
was using format to mark the bad sectors. Suddenly I got an idea of
not only marking the bad sector but also keeping the head from
accessing areas around the bad sector.

By the time I did this to my hard disks it had only 1 gb of its 2 gb
capacity usable. (You can imagine the number of bad sectors!).

The bad sectors developed during a three month period. After marking
the areas so the read head did not go anywhere near the bad sectors I
have been using this hard disk for more than two years without any new
bad sector appearing!

You can read my experience here

http://members.tripod.com/~diligent/ninelives.htm

HTH

--
Sandy Archer
Reply to newsgroups only
Anonymous
a b G Storage
July 26, 2004 6:02:21 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Ardent" <iam@here.com> wrote in message
news:5bi7g09uho70vvl04krriamdgltl23jeic@4ax.com...
> Hi All
>
> One of my hard disks continued to develop bad sectors and every time I

As soon as a HD begins to develop more than a very few bad sectors then
assume the HD is DOA as the rest will go bad soon. Replace the HD. We'll
keep your post as perfect proof of this point.

> was using format to mark the bad sectors. Suddenly I got an idea of
> not only marking the bad sector but also keeping the head from
> accessing areas around the bad sector.
>
> By the time I did this to my hard disks it had only 1 gb of its 2 gb
> capacity usable. (You can imagine the number of bad sectors!).
>
> The bad sectors developed during a three month period. After marking
> the areas so the read head did not go anywhere near the bad sectors I
> have been using this hard disk for more than two years without any new
> bad sector appearing!
>
> You can read my experience here
>
> http://members.tripod.com/~diligent/ninelives.htm
>
> HTH
>
> --
> Sandy Archer
> Reply to newsgroups only
Anonymous
a b G Storage
July 26, 2004 9:56:13 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Ron Reaugh" <ron-reaugh@worldnet.att.net> wrote in
news:NCZMc.325853$Gx4.193789@bgtnsc04-news.ops.worldnet.att.net:

> As soon as a HD begins to develop more than a very few bad sectors
> then assume the HD is DOA as the rest will go bad soon. Replace the
> HD. We'll keep your post as perfect proof of this point.

I consider anything > 0 bad sectors as meaning "The drive is dying,
immediately replace it"
Related resources
Anonymous
a b G Storage
July 26, 2004 12:02:11 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Nonsense. Your drive had bad sectors when it was shipped.

"Jim Berwick" <jimb@snip.net> wrote in message
news:Xns953213B4820A8jimbsnipnet@207.103.26.26...
>
> I consider anything > 0 bad sectors as meaning "The drive is dying,
> immediately replace it"
Anonymous
a b G Storage
July 26, 2004 7:21:36 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

lol, back in the old days (286, 386) harddrives weren't cheap so when an hd
developed bad sectors, the bad sector areas was partitioned off and never
used again :) 

"Ardent" <iam@here.com> wrote in message
news:5bi7g09uho70vvl04krriamdgltl23jeic@4ax.com...
> Hi All
>
> One of my hard disks continued to develop bad sectors and every time I
> was using format to mark the bad sectors. Suddenly I got an idea of
> not only marking the bad sector but also keeping the head from
> accessing areas around the bad sector.
>
> By the time I did this to my hard disks it had only 1 gb of its 2 gb
> capacity usable. (You can imagine the number of bad sectors!).
>
> The bad sectors developed during a three month period. After marking
> the areas so the read head did not go anywhere near the bad sectors I
> have been using this hard disk for more than two years without any new
> bad sector appearing!
>
> You can read my experience here
>
> http://members.tripod.com/~diligent/ninelives.htm
>
> HTH
>
> --
> Sandy Archer
> Reply to newsgroups only
Anonymous
a b G Storage
July 26, 2004 7:21:37 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Monster wrote:

> lol, back in the old days (286, 386) harddrives weren't cheap so when an
> hd developed bad sectors, the bad sector areas was partitioned off and
> never used again :) 

Still are. But it's handled transparently by drive now. When an IDE drive
is showing bad sectors it generally means that it's got more than the
onboard sparing can handle, which means that it's _real_ bad.

> "Ardent" <iam@here.com> wrote in message
> news:5bi7g09uho70vvl04krriamdgltl23jeic@4ax.com...
>> Hi All
>>
>> One of my hard disks continued to develop bad sectors and every time I
>> was using format to mark the bad sectors. Suddenly I got an idea of
>> not only marking the bad sector but also keeping the head from
>> accessing areas around the bad sector.
>>
>> By the time I did this to my hard disks it had only 1 gb of its 2 gb
>> capacity usable. (You can imagine the number of bad sectors!).
>>
>> The bad sectors developed during a three month period. After marking
>> the areas so the read head did not go anywhere near the bad sectors I
>> have been using this hard disk for more than two years without any new
>> bad sector appearing!
>>
>> You can read my experience here
>>
>> http://members.tripod.com/~diligent/ninelives.htm
>>
>> HTH
>>
>> --
>> Sandy Archer
>> Reply to newsgroups only

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
Anonymous
a b G Storage
July 26, 2004 7:21:38 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"J. Clarke" <jclarke@nospam.invalid> wrote in message
news:ce3db901m73@news2.newsguy.com...
> Monster wrote:
>
> > lol, back in the old days (286, 386) harddrives weren't cheap so when an
> > hd developed bad sectors, the bad sector areas was partitioned off and
> > never used again :) 
>
> Still are. But it's handled transparently by drive now. When an IDE drive
> is showing bad sectors it generally means that it's got more than the
> onboard sparing can handle, which means that it's _real_ bad.
>
There are around 100,000 spares on a 50GB drive. SMART would have said the
drive was toast long before they ran out.
July 26, 2004 8:18:06 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Eric Gisin wrote:

> Nonsense. Your drive had bad sectors when it was shipped.

Not that are visible. By the time you see any, there are really
quite a few. That's different from a few random ones at the time
of manufacture.

>
> "Jim Berwick" <jimb@snip.net> wrote in message
> news:Xns953213B4820A8jimbsnipnet@207.103.26.26...
>
>>I consider anything > 0 bad sectors as meaning "The drive is dying,
>>immediately replace it"
>
>


--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.
Anonymous
a b G Storage
July 26, 2004 8:18:07 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"CJT" <abujlehc@prodigy.net> wrote in message
news:41052EBE.3010701@prodigy.net...
> Eric Gisin wrote:
>
> > Nonsense. Your drive had bad sectors when it was shipped.
>
> Not that are visible. By the time you see any, there are really
> quite a few. That's different from a few random ones at the time
> of manufacture.
>
There are hundreds of initial bad sectors on each of my three SCSI drives.

It is quite normal to develop a few new ones each year, and that does NOT
indicate the drive is failing. Normally they are not visible, because they are
corrected and remapped.
Anonymous
a b G Storage
July 26, 2004 8:18:08 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

In article <ce3cl503ki@enews3.newsguy.com>,
Eric Gisin <ericgisin@graffiti.net> wrote:
>"CJT" <abujlehc@prodigy.net> wrote in message
>news:41052EBE.3010701@prodigy.net...
>> Eric Gisin wrote:
>>
>> > Nonsense. Your drive had bad sectors when it was shipped.
>>
>> Not that are visible. By the time you see any, there are really
>> quite a few. That's different from a few random ones at the time
>> of manufacture.
>>
>There are hundreds of initial bad sectors on each of my three SCSI drives.
>
>It is quite normal to develop a few new ones each year, and that does NOT
>indicate the drive is failing. Normally they are not visible, because they are
>corrected and remapped.
>


SMART monitering will tell you when if the device is within
manufacturer's tolerances. Everest from Lavalist is a nice package
(free for noncommercial use.) I don't have a link handy.

With XP I've seen an event log entry following a perceptable pause on
my PC. The log showed that a block had just meen remapped.

If I see a single additional block remapped on a machine being used
for revenue-producing business use I plan to swap that disk
out, asap.

I'd mark the disk and use it for some don't-care-if-burns purpose.
The disk doesn't get a third chance.

--
Al Dykes
-----------
adykes at p a n i x . c o m
Anonymous
a b G Storage
July 27, 2004 4:44:39 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Ardent" <iam@here.com> wrote in message news:5bi7g09uho70vvl04krriamdgltl23jeic@4ax.com...
> Hi All
>
> One of my hard disks continued to develop bad sectors and every time I
> was using format to mark the bad sectors. Suddenly I got an idea of
> not only marking the bad sector but also keeping the head from
> accessing areas around the bad sector.
>
> By the time I did this to my hard disks it had only 1 gb of its 2 gb
> capacity usable. (You can imagine the number of bad sectors!).
>
> The bad sectors developed during a three month period. After marking
> the areas so the read head did not go anywhere near the bad sectors I
> have been using this hard disk for more than two years without any new
> bad sector appearing!
>
> You can read my experience here
>
> http://members.tripod.com/~diligent/ninelives.htm

Several possible flaws in your method.

1) only works for drives smaller than 8GB

2) no drive has 256 physical heads and 63 sectors per track so
1 logical cylinder is already many physical cylinders
With 4 heads and ~600 sectors/tr. you already reserve ~6
physical cylinders per logical cylinder.

3) it's not the heads that need keeping away from the damaged
spots but the slider that they are mounted on, which is much
wider. The slider can cover into the hundreds of cylinders.

Btw, why not finish the experiment and zero-write the whole
drive and use it as one normally would, and see what happens.

If your theory is correct it should soon die. Somehow, I doubt that.

>
> HTH
>
> --
> Sandy Archer
> Reply to newsgroups only
Anonymous
a b G Storage
July 27, 2004 4:48:41 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"J. Clarke" <jclarke@nospam.invalid> wrote in message news:ce3db901m73@news2.newsguy.com...
> Monster wrote:
>
> > lol, back in the old days (286, 386) harddrives weren't cheap so when an
> > hd developed bad sectors, the bad sector areas was partitioned off and
> > never used again :) 
>
> Still are.

Nope.

> But it's handled transparently by drive now.

But doesn't reduce its capacity.

> When an IDE drive
> is showing bad sectors it generally means that it's got more than the
> the onboard sparing can handle, which means that it's _real_ bad.

Utterly Clueless.
When an IDE drive is showing bad sectors it generally means that
the "bad" sectors are unrecoverable read error bad sectors and
that the sparing system is incapable of replacing them as bad data
then would reappear as correct data in the replacement sector.

The unrecoverable read error bad sector will disappear nicely after
a write to the so-called "bad" sector.
"When an IDE drive is showing bad sectors it generally means" that
such a write to the 'so-called' "bad" sectors has not yet happened.

Ofcourse "J. Clarke" knows this as it has been explained to him
before but he prefers to troll.

>
> > "Ardent" <iam@here.com> wrote in message news:5bi7g09uho70vvl04krriamdgltl23jeic@4ax.com...
> >> Hi All
> >>
> >> One of my hard disks continued to develop bad sectors and every time I
> >> was using format to mark the bad sectors. Suddenly I got an idea of
> >> not only marking the bad sector but also keeping the head from
> >> accessing areas around the bad sector.
> >>
> >> By the time I did this to my hard disks it had only 1 gb of its 2 gb
> >> capacity usable. (You can imagine the number of bad sectors!).
> >>
> >> The bad sectors developed during a three month period. After marking
> >> the areas so the read head did not go anywhere near the bad sectors I
> >> have been using this hard disk for more than two years without any new
> >> bad sector appearing!
> >>
> >> You can read my experience here
> >>
> >> http://members.tripod.com/~diligent/ninelives.htm
> >>
> >> HTH
> >>
> >> --
> >> Sandy Archer
> >> Reply to newsgroups only
>
> --
> --John
> Reply to jclarke at ae tee tee global dot net
> (was jclarke at eye bee em dot net)
Anonymous
a b G Storage
July 27, 2004 5:06:07 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Jim Berwick" <jimb@snip.net> wrote in message news:Xns953213B4820A8jimbsnipnet@207.103.26.26
> "Ron Reaugh" <ron-reaugh@worldnet.att.net> wrote in news:NCZMc.325853$Gx4.193789@bgtnsc04-news.ops.worldnet.att.net:
>
> > As soon as a HD begins to develop more than a very few bad sectors
> > then assume the HD is DOA as the rest will go bad soon. Replace
> > the HD. We'll keep your post as perfect proof of this point.
>
> I consider anything > 0 bad sectors as meaning "The drive is dying,
> immediately replace it"

Well, maybe you should look into your S.M.A.R.T. data then, every hour.
It might be in it's death throws already and you not even know it.
Anonymous
a b G Storage
July 28, 2004 7:16:05 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

On Mon, 26 Jul 2004 08:02:11 -0700, Eric Gisin <ericgisin@graffiti.net> wrote:
>Nonsense. Your drive had bad sectors when it was shipped.

Modern hard drives do bad block forwarding, invisible to the operating
system and thus the end user. If you start actually seeing bad blocks
it means that all the spares have been used and the drive is in the
process of dying a grievous death.

--
Roger Blake
(Subtract 10 for email.)
Anonymous
a b G Storage
July 28, 2004 7:16:06 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Roger Blake" <rogblake10@iname10.com> wrote in message
news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> Modern hard drives do bad block forwarding, invisible to the operating
> system and thus the end user. If you start actually seeing bad blocks
> it means that all the spares have been used and the drive is in the
> process of dying a grievous death.

I don't think that's quite right based on my understanding. If you're
WRITING to the block when the error is first detected by the drive, then the
reallocation is invisible to the OS. However, if a READ is the first time
the error is detected, then an error is returned to the OS (and it will
"detect" a bad block), but the disk then places that block number in a
pending list and the reallocation isn't done the next time it is written to.
Thus, the OS could see an error before the spares have been exhausted.

This process is described in most detailed data sheets for the drives, and
the 5 or so that I've read seem to follow this general process.
Anonymous
a b G Storage
July 28, 2004 7:16:06 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Clueless gibberish. Read my and Folkert's reply to J Clarke.

"Roger Blake" <rogblake10@iname10.com> wrote in message
news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
>
> Modern hard drives do bad block forwarding, invisible to the operating
> system and thus the end user. If you start actually seeing bad blocks
> it means that all the spares have been used and the drive is in the
> process of dying a grievous death.
>
Anonymous
a b G Storage
July 28, 2004 7:46:34 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Taed Wynnell wrote:

> "Roger Blake" <rogblake10@iname10.com> wrote in message
> news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
>> Modern hard drives do bad block forwarding, invisible to the operating
>> system and thus the end user. If you start actually seeing bad blocks
>> it means that all the spares have been used and the drive is in the
>> process of dying a grievous death.
>
> I don't think that's quite right based on my understanding. If you're
> WRITING to the block when the error is first detected by the drive, then
> the
> reallocation is invisible to the OS. However, if a READ is the first time
> the error is detected, then an error is returned to the OS (and it will
> "detect" a bad block), but the disk then places that block number in a
> pending list and the reallocation isn't done the next time it is written
> to. Thus, the OS could see an error before the spares have been exhausted.
>
> This process is described in most detailed data sheets for the drives, and
> the 5 or so that I've read seem to follow this general process.

If one is being pedantically correct then yes, it's possible to see bad
sectors before the sparing is exhausted. In the real world if you're
seeing bad sectors on an IDE drive, assume the drive is in the transition
phase between "merely dead" and "sincerely dead".

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
July 28, 2004 8:44:57 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Taed Wynnell wrote:
> "Roger Blake" <rogblake10@iname10.com> wrote in message
> news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
>
>>Modern hard drives do bad block forwarding, invisible to the operating
>>system and thus the end user. If you start actually seeing bad blocks
>>it means that all the spares have been used and the drive is in the
>>process of dying a grievous death.
>
>
> I don't think that's quite right based on my understanding. If you're
> WRITING to the block when the error is first detected by the drive, then the
> reallocation is invisible to the OS.

Are you implying drives do a read-after-write check? If not (and I
don't think they do such a check routinely), it seems to me the only
way a drive would ever detect such an error (i.e. upon a write) is
if things are so hosed the drive can't even sync to the write location.

However, if a READ is the first time
> the error is detected, then an error is returned to the OS (and it will
> "detect" a bad block), but the disk then places that block number in a
> pending list and the reallocation isn't done the next time it is written to.
> Thus, the OS could see an error before the spares have been exhausted.
>
> This process is described in most detailed data sheets for the drives, and
> the 5 or so that I've read seem to follow this general process.
>
>


--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.
July 28, 2004 9:41:09 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

My experience is that Blake is correct. Bad blocks, once seen, grow like
weeds.

Eric Gisin wrote:
>
> Clueless gibberish. Read my and Folkert's reply to J Clarke.
>
> "Roger Blake" <rogblake10@iname10.com> wrote in message
> news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> >
> > Modern hard drives do bad block forwarding, invisible to the operating
> > system and thus the end user. If you start actually seeing bad blocks
> > it means that all the spares have been used and the drive is in the
> > process of dying a grievous death.
> >
Anonymous
a b G Storage
July 28, 2004 9:41:10 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Many of us have reported seeing bad blocks caused by power problems,
which cease when that is fixed.

The explanation "running out of spare sectors" is absolutely idiotic. It is
not possible to remap that many without getting lots of prior warning.

"Wizard" <mskmywvcaqs@grubx.com> wrote in message
news:4107E535.79B81BA6@grubx.com...
> My experience is that Blake is correct. Bad blocks, once seen, grow like
> weeds.
>
> Eric Gisin wrote:
> >
> > Clueless gibberish. Read my and Folkert's reply to J Clarke.
> >
> > "Roger Blake" <rogblake10@iname10.com> wrote in message
> > news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> > >
> > > Modern hard drives do bad block forwarding, invisible to the operating
> > > system and thus the end user. If you start actually seeing bad blocks
> > > it means that all the spares have been used and the drive is in the
> > > process of dying a grievous death.
> > >
Anonymous
a b G Storage
July 29, 2004 12:39:09 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

In article <4107D808.1090703@prodigy.net>, CJT <abujlehc@prodigy.net> wrote:
>Taed Wynnell wrote:
>> "Roger Blake" <rogblake10@iname10.com> wrote in message
>> news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
>>
>>>Modern hard drives do bad block forwarding, invisible to the operating
>>>system and thus the end user. If you start actually seeing bad blocks
>>>it means that all the spares have been used and the drive is in the
>>>process of dying a grievous death.
>>
>>
>> I don't think that's quite right based on my understanding. If you're
>> WRITING to the block when the error is first detected by the drive, then the
>> reallocation is invisible to the OS.
>
>Are you implying drives do a read-after-write check? If not (and I
>don't think they do such a check routinely), it seems to me the only
>way a drive would ever detect such an error (i.e. upon a write) is
>if things are so hosed the drive can't even sync to the write location.
>
>However, if a READ is the first time
>> the error is detected, then an error is returned to the OS (and it will
>> "detect" a bad block), but the disk then places that block number in a
>> pending list and the reallocation isn't done the next time it is written to.
>> Thus, the OS could see an error before the spares have been exhausted.
>>
>> This process is described in most detailed data sheets for the drives, and
>> the 5 or so that I've read seem to follow this general process.
>>
>>
>


Modern Disks have a huge percentage of the raw capacity decicated to
ECC (error correction codes) which is enough redundant data so that if
a block is unreadable the ECC codes will allow the data to be
recalculated and nothing is lost. When ECC recovery happens the block
is redirected to a spare, the data is written there and the
application has know idea anything happened. SMART data will tell you
how many times this has happened.




--
Al Dykes
-----------
adykes at p a n i x . c o m
Anonymous
a b G Storage
July 29, 2004 4:22:26 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Wizard" <mskmywvcaqs@grubx.com> wrote in message news:4107E535.79B81BA6@grubx.com...
> My experience is that Blake is correct.

And another one from the school of hard knocks.

No, that is not what he said, it has nothing to do with the spare
pool being exhausted. Only how a "bad" sector manifests itself.

> Bad blocks, once seen, grow like weeds.

Yup, until you stop what's causing them.
Unrecoverable read error bad sectors are usually
caused by bad power supply or drives overheating.

>
> Eric Gisin wrote:
> >
> > Clueless gibberish. Read my and Folkert's reply to J Clarke.
> >
> > "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> > >

["Clueless gibberish" snipped]
Anonymous
a b G Storage
July 29, 2004 4:22:27 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

In article <2mqs11Fqeac5U2@uni-berlin.de>,
Folkert Rienstra <folkertdotrienstra@freeler.nl> wrote:
>
>"Wizard" <mskmywvcaqs@grubx.com> wrote in message news:4107E535.79B81BA6@grubx.com...
>> My experience is that Blake is correct.
>
>And another one from the school of hard knocks.
>
>No, that is not what he said, it has nothing to do with the spare
>pool being exhausted. Only how a "bad" sector manifests itself.
>
>> Bad blocks, once seen, grow like weeds.
>
>Yup, until you stop what's causing them.
>Unrecoverable read error bad sectors are usually
>caused by bad power supply or drives overheating.
>

IMHO once I see bad blocks the disk gets yanked and replaced on any PC
that's being used for business purposes. Life't too short to have
unexpected total failures.


>>
>> Eric Gisin wrote:
>> >
>> > Clueless gibberish. Read my and Folkert's reply to J Clarke.
>> >
>> > "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
>> > >
>
>["Clueless gibberish" snipped]


--
Al Dykes
-----------
adykes at p a n i x . c o m
Anonymous
a b G Storage
July 29, 2004 4:22:29 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Another clueless parrot troll.

"Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> On Mon, 26 Jul 2004 08:02:11 -0700, Eric Gisin <ericgisin@graffiti.net> wrote:
> >Nonsense. Your drive had bad sectors when it was shipped.
>
> Modern hard drives do bad block forwarding, invisible to the operating
> system and thus the end user. If you start actually seeing bad blocks
> it means that all the spares have been used and the drive is in the
> process of dying a grievous death.
>
> --
> Roger Blake
> (Subtract 10 for email.)
Anonymous
a b G Storage
July 29, 2004 4:22:34 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Next time, proofread your post before sending please.

"Taed Wynnell" <taedn@REMOVETHIS.vertical.com> wrote in message news:Y9QNc.1429$qo6.1874@news.uswest.net...
> "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> > Modern hard drives do bad block forwarding, invisible to the operating
> > system and thus the end user. If you start actually seeing bad blocks
> > it means that all the spares have been used and the drive is in the
> > process of dying a grievous death.
>
> I don't think that's quite right based on my understanding.

> If you're WRITING to the block when the error is first detected
> by the drive, then the reallocation is invisible to the OS.

Only on 'sector not found', which isn't a possibility on recent drives without
sector IDs. Faulty writes will only be noticed on the next read to the sector.

> However, if a READ is the first time the error is detected, then
> an error is returned to the OS (and it will "detect" a bad block),

Only when it is an unrecoverable read error bad sector. Recoverable read
error bad sectors are the ones that are replaced directly (if needbe).

> but the disk then places that block number in a pending list and the reallocation

> isn't done

is done

> the next time it is written to.
> Thus, the OS could see an error before the spares have been exhausted.

Correct for unrecoverable read error bad sectors.

>
> This process is described in most detailed data sheets for the drives,
> and the 5 or so that I've read seem to follow this general process.

Correct, except that it is not like you explained here.

>
>
Anonymous
a b G Storage
July 29, 2004 4:22:42 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"CJT" <abujlehc@prodigy.net> wrote in message news:4107D808.1090703@prodigy.net...
> Taed Wynnell wrote:
> > "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> >
> > > Modern hard drives do bad block forwarding, invisible to the operating
> > > system and thus the end user. If you start actually seeing bad blocks
> > > it means that all the spares have been used and the drive is in the
> > > process of dying a grievous death.
> >
> >
> > I don't think that's quite right based on my understanding. If you're
> > WRITING to the block when the error is first detected by the drive,
> > then the reallocation is invisible to the OS.
>
> Are you implying drives do a read-after-write check?

Maybe, maybe not, judged by the other typo and
that he says to have read the drive documentation.

> If not (and I don't think they do such a check routinely),

They don't. Only for sectors in the bad sector candidate (pending) list.

> it seems to me the only way a drive would ever detect such an error
> (i.e. upon a write) is if things are so hosed the drive can't even sync
> to the write location.

Right, and that doesn't happen anymore on current harddrives unless the
servo marks have been damaged and more than one sector will be lost.

Bad sectors are reallocated on recoverable reads or writes to bad sector
candidates.

>
> > However, if a READ is the first time the error is detected, then an error
> > is returned to the OS (and it will "detect" a bad block), but the disk then
> > places that block number in a pending list and the reallocation isn't done
> > the next time it is written to.
> > Thus, the OS could see an error before the spares have been exhausted.
> >
> > This process is described in most detailed data sheets for the drives,
> > and the 5 or so that I've read seem to follow this general process.
> >
>
Anonymous
a b G Storage
July 29, 2004 4:24:59 AM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

On Tue, 27 Jul 2004 00:44:39 +0200, "Folkert Rienstra"
<see_reply-to@myweb.nl> wrote:


>1) only works for drives smaller than 8GB

Could be. Unfortunately :-) all my large disks have no bad sectors to
try with!

>Btw, why not finish the experiment and zero-write the whole
>drive and use it as one normally would, and see what happens.

I have tried this with other drives earlier and bad sectors remained
bad :-(

>If your theory is correct it should soon die. Somehow, I doubt that.

As I said the particular drive progressively developed the bad sectors
during a period of three months - after doing what I did the disk is
continuing to work for me for a little more than two years without
developing any new bad sector.

I posted my experiment as I am sure there are a lot of DOS aficionados
using smaller disks and trying all sorts of things with hard disks, as
frequently seen in posts here and elsewhere.

Thanks for your comments

Sandy Archer
Anonymous
a b G Storage
July 29, 2004 5:34:20 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

adykes@panix.com (Al Dykes) wrote:

>Modern Disks have a huge percentage of the raw capacity decicated to
>ECC (error correction codes) which is enough redundant data so that if
>a block is unreadable the ECC codes will allow the data to be
>recalculated and nothing is lost.

Huh? Maybe you're thinking of CDROM's, but not HD's...
Anonymous
a b G Storage
July 29, 2004 6:51:44 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

In article <hogig0h0dp9l67ebdlrqjf29mojmjnma51@4ax.com>,
chrisv <chrisv@nospam.invalid> wrote:
>adykes@panix.com (Al Dykes) wrote:
>
>>Modern Disks have a huge percentage of the raw capacity decicated to
>>ECC (error correction codes) which is enough redundant data so that if
>>a block is unreadable the ECC codes will allow the data to be
>>recalculated and nothing is lost.
>
>Huh? Maybe you're thinking of CDROM's, but not HD's...
>


Yup;

http://www.storagereview.com/guide2000/ref/hdd/geom/err...

(Actually I believe data CDs have two layers of ECC, one in the media
layer, and one at something below the filesystem level. I can't get a
reference for this.)

--
Al Dykes
-----------
adykes at p a n i x . c o m
Anonymous
a b G Storage
July 29, 2004 8:25:53 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Ardent" <iam@here.com> wrote in message news:gsffg01pf4572rkvvqgqgr8srpeisk4qsn@4ax.com
> On Tue, 27 Jul 2004 00:44:39 +0200, "Folkert Rienstra" <see_reply-to@myweb.nl> wrote:
>
> > 1) only works for drives smaller than 8GB
>
> Could be. Unfortunately :-) all my large disks have no bad sectors to
> try with!
>
> > Btw, why not finish the experiment and zero-write the whole
> > drive and use it as one normally would, and see what happens.
>
> I have tried this with other drives earlier

But you didn't do it with *this* drive, the one that you did the ex-
periment on.

> and bad sectors remained bad :-(

Then either the drives didn't have bad sector management or they
had exhausted their spare sector pool already.

>
> > If your theory is correct it should soon die. Somehow, I doubt that.
>
> As I said the particular drive progressively developed the bad sectors
> during a period of three months - after doing what I did the disk is
> continuing to work for me for a little more than two years without
> developing any new bad sector.

Yes, I read it the first time.

>
> I posted my experiment as I am sure there are a lot of DOS aficionados
> using smaller disks and trying all sorts of things with hard disks, as
> frequently seen in posts here and elsewhere.

Yes, but your experiment doesn't count for anything if you don't finish it
an no hard conclusions can be drawn from it.

The 'fact' that you think that you never touched the areas that you took
out of use is no fact at all as drives heads patrol the surfaces in order
to not heat-up the heads and platters tracks when idle.

>
> Thanks for your comments
>
> Sandy Archer
Anonymous
a b G Storage
July 29, 2004 8:35:48 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Complete and utterly clueless drivel.
The trolls are out in full force this week.

"Al Dykes" <adykes@panix.com> wrote in message news:ce9gvd$ivm$1@panix3.panix.com
> In article <4107D808.1090703@prodigy.net>, CJT <abujlehc@prodigy.net> wrote:
> > Taed Wynnell wrote:
> > > "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> > >
> > > > Modern hard drives do bad block forwarding, invisible to the operating
> > > > system and thus the end user. If you start actually seeing bad blocks
> > > > it means that all the spares have been used and the drive is in the
> > > > process of dying a grievous death.
> > >
> > >
> > > I don't think that's quite right based on my understanding. If you're
> > > WRITING to the block when the error is first detected by the drive,
> > > then the reallocation is invisible to the OS.
> >
> > Are you implying drives do a read-after-write check? If not (and I
> > don't think they do such a check routinely), it seems to me the only
> > way a drive would ever detect such an error (i.e. upon a write) is
> > if things are so hosed the drive can't even sync to the write location.
> >
> > > However, if a READ is the first time
> > > the error is detected, then an error is returned to the OS (and it will
> > > "detect" a bad block), but the disk then places that block number in a
> > > pending list and the reallocation isn't done the next time it is written to.
> > > Thus, the OS could see an error before the spares have been exhausted.
> > >
> > > This process is described in most detailed data sheets for the drives, and
> > > the 5 or so that I've read seem to follow this general process.
> > >
> >
>
>

> Modern Disks have a huge percentage of the raw capacity decicated to
> ECC (error correction codes) which is enough redundant data so that if
> a block is unreadable the ECC codes will allow the data to be
> recalculated and nothing is lost.

If a block is unreadable it means that the ECC codes failed
to allow the data to be recalculated and data *is* lost.

> When ECC recovery happens the block is redirected to a spare

Only when a set number of retries was needed to accomplish a corrected read.
Sectors that are read with ECC corrections without several retries will not be
reallocated at all.

> the data is written there and the application has know idea anything happened.

> SMART data will tell you how many times this has happened.
Anonymous
a b G Storage
July 29, 2004 8:40:04 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

"Al Dykes" <adykes@panix.com> wrote in message news:ce9h3u$j4d$1@panix3.panix.com
> In article <2mqs11Fqeac5U2@uni-berlin.de>, Folkert Rienstra <reply address removed> wrote:

Dykes, you are a clueless troll, that can't even setup his news
client properly or worse, refuses to do so enjoying submitting
peoples reply addresses to the spammers just to annoy them.

And replacing a blown tyre is of little use when the road is
full of spikes, Dykes, nomatter how humble your opinion.


> >
> > "Wizard" <mskmywvcaqs@grubx.com> wrote in message news:4107E535.79B81BA6@grubx.com...
> > > My experience is that Blake is correct.
> >
> > And another one from the school of hard knocks.
> >
> > No, that is not what he said, it has nothing to do with the spare
> > pool being exhausted. Only how a "bad" sector manifests itself.
> >
> > > Bad blocks, once seen, grow like weeds.
> >
> > Yup, until you stop what's causing them.
> > Unrecoverable read error bad sectors are usually
> > caused by bad power supply or drives overheating.
> >
>
> IMHO once I see bad blocks the disk gets yanked and replaced on any PC
> that's being used for business purposes. Life't too short to have
> unexpected total failures.
>
>
> > >
> > > Eric Gisin wrote:
> > > >
> > > > Clueless gibberish. Read my and Folkert's reply to J Clarke.
> > > >
> > > > "Roger Blake" <rogblake10@iname10.com> wrote in message news:slrncgfgpk.las.rogblake10@unix2.netaxs.com...
> > > > >
> >
> > ["Clueless gibberish" snipped]
Anonymous
a b G Storage
July 29, 2004 8:40:05 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Folkert Rienstra wrote:

> Dykes, you are a clueless troll, that can't even setup his news
> client properly or worse, refuses to do so enjoying submitting
> peoples reply addresses to the spammers just to annoy them.

folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
folkert.rienstra@freeler.nl
Anonymous
a b G Storage
July 29, 2004 8:40:06 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.computer (More info?)

Kadaitcha Man wrote:

>(snip)

What's wrong, K-man? Too scared to use your "real name" while
engaging in your sociopathic behavior?
Anonymous
a b G Storage
July 29, 2004 10:28:42 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"chrisv" <chrisv@nospam.invalid> wrote in message
news:hogig0h0dp9l67ebdlrqjf29mojmjnma51@4ax.com...
> adykes@panix.com (Al Dykes) wrote:
>
> >Modern Disks have a huge percentage of the raw capacity decicated to
> >ECC (error correction codes) which is enough redundant data so that if
> >a block is unreadable the ECC codes will allow the data to be
> >recalculated and nothing is lost.
>
> Huh? Maybe you're thinking of CDROM's, but not HD's...
>
A hard drive uses about 400 bits/sector ECC - 10%, a CD-ROM uses 20% for
top-level ECC.
Anonymous
a b G Storage
July 30, 2004 11:34:09 PM

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Al Dykes" <adykes@panix.com> wrote in message news:cebh00$ag2$1@panix3.panix.com...
> In article <hogig0h0dp9l67ebdlrqjf29mojmjnma51@4ax.com>, chrisv <chrisv@nospam.invalid> wrote:
> > adykes@panix.com (Al Dykes) wrote:
> >
> > > Modern Disks have a huge percentage of the raw capacity decicated to
> > > ECC (error correction codes) which is enough redundant data so that if
> > > a block is unreadable the ECC codes will allow the data to be recalculated
> > > and nothing is lost.
> >
> > Huh? Maybe you're thinking of CDROM's, but not HD's...
> >
> > > When ECC recovery happens the block is redirected to a spare, the data
> > > is written there and the application has know idea anything happened.
> >
>
>
> Yup;
>
> http://www.storagereview.com/guide2000/ref/hdd/geom/err...

Which obviously you didn't bother to read or didn't understand a word of:

"
When a sector is written to the hard disk, the appropriate ECC codes
are generated and stored in the bits reserved for them. When the
sector is read back, the user data read, combined with the ECC bits,
*can tell the controller if any errors occurred during the read*.
Errors that can be corrected using the redundant information
are corrected before passing the data to the rest of the system.
* The system can also tell when there is too much damage to the *
* data to correct, and will issue an error notification in that event. *
The sophisticated firmware present in all modern drives uses
ECC *as part of its overall error management protocols*.
This is all done * "on the fly" * with no intervention from the user
required, and no slowdown in performance even when errors are
encountered and must be corrected.
"

http://www.storagereview.com/guide2000/ref/hdd/geom/err...

"
The hard disk's controller employs a sequence of sophisticated tech-
niques to manage errors that occur when reading data from the disk.
In a way, the system is kind of like a *troubleshooting flowchart*.
When a problem occurs, the simplest techniques are tried first, and
*if they don't work, the problem is escalated to a higher level*.
Every manufacturer uses different techniques, so this is just a rough
example guideline of how a hard disk will approach error management:

ECC Error Detection: The sector is read, and error detection is applied
to *check for any read errors*. If there are no errors, the sector is
passed on to the interface and the read is concluded successfully.

ECC Error Correction: The controller will attempt to correct the error
using the ECC codes read for the sector. The data can be corrected
very quickly using these codes, normally "on the fly" with no delay.
* If this is the case, the data is fixed and the read considered successful. *
Most drive manufacturers consider this occurrence common enough that
* it is not even considered a "real" read error. *
An error corrected at this level can be considered "automatically corrected".

Automatic Retry: The next step is usually to wait for the disk to spin
around again, and retry the read. Sometimes the first error can be
caused by a stray magnetic field, physical shock or other non-repeating
problem, and the retry will work. If it doesn't, more retries may be done.
Most controllers are programmed to retry the sector a certain number
of times before giving up.
* An error corrected after a straight retry is often *
* considered "recovered" or "corrected after retry". *

Advanced Error Correction: Many drives will, on subsequent retries
after the first, invoke more advanced error correction algorithms that
are slower and more complex than the regular correction protocols, but
have an increased chance of success.
* These errors are "recovered after multiple reads" *
* or "recovered after advanced correction". *

Failure: If the sector still cannot be read, the drive will signal a read
error to the system.
* These are "real", unrecoverable read errors, the kind *
* that result in a dreaded error message on the screen. *
"

http://www.storagereview.com/guide2000/ref/hdd/geom/err...

"Many drives are smart enough to realize that if a sector can only be read
after retries, the chances are good that something bad may be happening
to that sector, and the next time it is read it might not be recoverable.
For this reason, the drive will usually do something when it has to use
retries to read a sector
*(but usually not when ECC will correct the problem on the fly)*.
What the drive does depends on how it is designed."
"

From the Hitachi Deskstar 180 GXP manual :

"
9.11.1 Auto Reassign function
The sectors which show some errors may be reallocated automatically
when specific conditions are met.
The spare tracks for reallocation are located at regular intervals from
Cylinder 0. The conditions for auto-reallocation are described below.

9.11.1.1 Nonrecovered write errors
When a write operation cannot be completed after the Error Recovery
Procedure (ERP) is fully carried out, the sector(s) are reallocated to the
spare location. An error is reported to the host system only when the write
cache is disabled and the auto reallocation has failed.
If the Write Cache function is ENABLED when the number of available
spare sectors reaches 0 sector, both Auto Reassign function and Write
Cache function are automatically disabled.

9.11.1.2 Nonrecovered read errors
When a read operation has failed after defined ERP is fully carried out,
a hard error is reported to the host system.
* This location is registered internally as a candidate for reallocation *.
When a registered location is specified as a target of a write operation,
a sequence of media verification is performed automatically. When the
result of this verification meets the criteria, this sector is reallocated.

9.11.1.3 Recovered read errors
When a read operation for a sector has failed once and then has recovered
*at the specific ERP step*, this sector of data is automatically reallocated.
A media verification sequence may be run prior to the reallocation according
to the predefined conditions.
"

Note: Advanced Error Correction = ERP (Error recovery procedure)

>
> (Actually I believe

Your beliefs are obviously dangerous.

> data CDs have two layers of ECC, one in the media
> layer, and one at something below the filesystem level.

> I can't get a reference for this.)

How fortunate for you as it probably would prove you wrong again.

>

So to conclude:

ECC Error Correction:

*If this is the case, the data is fixed and the read considered successful*.
*it is not even considered a "real" read error*.
An error corrected at this level can be considered "automatically corrected".

Sparing:

Many drives are smart enough to realize that if a sector can only be read
after *retries*, the chances are good that something bad may be happening
to that sector, and the next time it is read it might not be recoverable.
For this reason, the drive will usually do something when it has to use
retries to read a sector.

Recovered read error bad sectors are spared only after the (a spe-
cific) ERP step (Advanced Error Correction step) has been entered.

> > > When ECC recovery happens the block is redirected to a spare, the data
> > > is written there and the application has know idea anything happened.

A complete fabrication by someone who obviously hasn't got a clue.
!