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OT: bad sector remapping

There *never* will be anything to "recover" on it. I don't use laptops for anything other than "small GUI's". A friend will be using this one to access email, browse the web and view pictures from digital camera. I.e., all things that exist *outside* the PC's disk.

I volunteer at a recycling facility. This attitude is far too common. "Recycled" machines (at most such places) I *scrapped* for precious metals, etc. A huge waste of resources for something that is typically still "serviceable" (it is not uncommon for an 18-wheeler to pull up FULL of PC's to be recycled -- just because some business decided that it's been 18 months since they last purchased machines... :-/ ). Unfortunately, it takes a lot of labor to reintroduce a machine into normal use once it has gone this route. But, schools, charities, etc. sure appreciate NOT having to pay for them!

I would prefer not to be a part of that problem.

Reply to
D Yuniskis
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Modern drives can't be low level formatted by the user, but not because of the servo, which is written between the sectors or more deeply than the other information. One early drive with an embedded servo was the Toshiba MK-72x, an ST506/412 interface drive with 10 heads and 5 platters, and it could definitely be low level formatted.

Reply to
do_not_spam_me

First HD I owned was a Kalok 330 RLL. I think it was around 30 megabytes. The DEBUG command was used to low level format these and MFM drives. Usually on an AT/XT PC it was > debug.com then G=C800:5.

Do you go back that far?

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Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

I've rewritten timing tracks on DEC DF32 and RF08 head-per-track drives when you were in grade school.

Reply to
Jim Stewart

So is this "MY COCK IS BIGGER THAN YOURS" contest for you or do you really think I give a f*ck what you did or when you did it.

BTW I was is high school back when you were fiddling wither your DIC.

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Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

On 12/22/2010 11:01 AM Meat Plow spake thus:

Ah, Meat Head shows his good manners again ...

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Comment on quaint Usenet customs, from Usenet:

   To me, the *plonk...* reminds me of the old man at the public hearing
   who stands to make his point, then removes his hearing aid as a sign
   that he is not going to hear any rebuttals.
Reply to
David Nebenzahl

The Revenge Dweeb chimes in right on cue. I never claimed to have good manners you simpering f****it. Don't like what I post, don't read it.

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Live Fast, Die Young and Leave a Pretty Corpse
Reply to
Meat Plow

On Tue, 21 Dec 2010 11:39:01 -0700, D Yuniskis put finger to keyboard and composed:

The drive will wait for a Write command from the host (ie the OS) before it processes a "pending" sector. When a write command is issued, the drive retests the pending sector and returns it to service if good, or reallocates the LBA to a spare sector if bad.

If CHKDSK finds a bad sector, then it takes it out of service and adds it to the $BADCLUS metafile in the case of NTFS, or marks it as bad in the File Allocation Table in the case of FAT16 or FAT32. Thereafter the sector is never accessed again until the next time the drive is formatted. In fact my own Seagate drive had 1 pending sector for its entire life because Windows 98's Scandisk had marked it as bad.

In short, the list of bad clusters maintained by the OS, and the lists of grown and factory defects (G-list and P-list) maintained by the drive, are essentially unrelated. In fact, once a sector has made it into into the G-list, it becomes invisible to the OS. All that the OS sees is an LBA (Logical Block Address), not a physical sector. Remapping or reallocation is the process by which the drive transparently takes a sector from a pool of spares and assigns it to a particular unreadable LBA. The host is never aware that this has happened.

- Franc Zabkar

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Reply to
Franc Zabkar

On Mon, 20 Dec 2010 18:47:49 -0700, D Yuniskis put finger to keyboard and composed:

Use a comprehensive SMART diagnostic tool. Look for reallocated, pending, or uncorrectable sectors.

HD Sentinel (DOS / Windows / Linux):

formatting link

HDDScan for Windows:

formatting link

See this article for SMART info:

formatting link

MHDD can also display the SMART data.

A "low level format" on modern drives merely writes zeros to each sector. It doesn't actually perform a real LLF. After zeroing the drive, any "pending" sectors will be transparently retested and reallocated with spares, if necessary.

- Franc Zabkar

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Reply to
Franc Zabkar

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