Windows 2K - poor handling of FAT bad sectors

  • Thread starter Thread starter Eric Gisin
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Eric Gisin

Windows 2K does not handle bad sectors in the FAT of a FAT32 volume very well.
Applications return a variety of misleading error messages which confuse even
experienced users.

The first access to a FAT32 volume results in a read of the boot sector,
followed by many 4KB reads of the first FAT. If it encounters a bad sector,
the volume mount fails.

When you logon, the desktop will be slow to launch. It is accessing the volume
many times. You can run cmd from task manager.

In My Computer, the drive shows as "local disk". Attempting to open it results
in the message "The disk in drive X is not formatted. Do you want to format
it?" (don't).

Accessing it with dir from cmd results in something like "the file system is
not recognized" (boot sector is fine). Chkdsk says "errors found, cannot
continue... ".

In my case, I read both FATs with dskprobe. Both have errors. Should I use
chkdsk/f or manually copy a sector from the good fat to the bad?
 
Eric Gisin said:
Windows 2K does not handle bad sectors in the FAT of a FAT32 volume very well.
Applications return a variety of misleading error messages which confuse even
experienced users.
Click to expand...

It's pretty much the same for all MS operating systems. They all have poor
handling of bad sectors even when bad sectors occur in area's which are
mirrored, like the FAT or a boot sector. Also handling of sectors which do
not contain really vital info like the FSinfo sector cause problem which
can't be overcome. The FSinfo example *can* be overcome by booting a non MS
based DOS version like Caldera (which seems to ignore the FSinfo sector).
Fro the record, with FSinfo sector I mean the extended boot sector on FAT32
partitions where information like the first free cluster is recorded.
In My Computer, the drive shows as "local disk". Attempting to open it results
in the message "The disk in drive X is not formatted. Do you want to format
it?" (don't).

Accessing it with dir from cmd results in something like "the file system is
not recognized" (boot sector is fine). Chkdsk says "errors found, cannot
continue... ".

In my case, I read both FATs with dskprobe. Both have errors. Should I use
chkdsk/f or manually copy a sector from the good fat to the bad?
Click to expand...

You mean read errors? You just mentioned earlier that chkdsk doesn't work
.... What you want, in plain language, is to enforce a read action to the bad
sectors and hope the disks internal error management kicks in and replaces
the bad sector with ione from the spare pool. It has been mentioned in this
group before that Spinrite was succesful in doing that (discussion was if
Spinrite actually enforced a replacement of the sector, or that it did
'repair' the sector all by itself).

Another option is to clone the disk sector-by-sector with a tool that can
deal with bad sectors on the source drive. Then on the destination drive
repair of the FAT can be attempted.
 
not contain really vital info like the FSinfo sector cause problem which
can't be overcome. The FSinfo example *can* be overcome by booting a non MS
based DOS version like Caldera (which seems to ignore the FSinfo sector).
Click to expand...

FASTFAT ignores FSInfo sector contents, though writes to it to maintain the
DOS-compatible state.
 
Eric Gisin said:
Windows 2K does not handle bad sectors in the FAT of a FAT32 volume very well.
Applications return a variety of misleading error messages which confuse even
experienced users.

The first access to a FAT32 volume results in a read of the boot sector,
followed by many 4KB reads of the first FAT. If it encounters a bad sector,
the volume mount fails.

When you logon, the desktop will be slow to launch. It is accessing the volume
many times. You can run cmd from task manager.

In My Computer, the drive shows as "local disk". Attempting to open it results
in the message "The disk in drive X is not formatted. Do you want to format
it?" (don't).

Accessing it with dir from cmd results in something like "the file system is
not recognized" (boot sector is fine). Chkdsk says "errors found, cannot
continue... ".

In my case, I read both FATs with dskprobe. Both have errors. Should I use
chkdsk/f or manually copy a sector from the good fat to the bad?
Click to expand...

Svend has a tool that can do that for logical errors.
It remains to be seen how well it does on physical ones, though.
 
Svend has a tool that can do that for logical errors.
It remains to be seen how well it does on physical ones, though.
Click to expand...

Hi.

Is it free tool?
If yes where I can download it?

I have similar problems, but I need to scan my disk and mark all bad sectors
and mark in addition few preceding- and following- good sectors wchich may
become bad in near future.

My problem is: during normal scandisk work some bad sectors was read
succesfully after few rerties (i guess: taken by diskcontroller or O.S.) and
they are NOT marked as bad.
Of course during normal operation (due to "Murphy laws") O.S. many times
encounter "almost bad sector" and wastes more than 5 secs on retries.
I need such a tool which scans surface and when encounters one (or two)
unsuccesful sector read - decides to mark this sector. (At this time I do
not care about data on that partition - I have backup)

best regards
 
Svend has a tool that can do that for logical errors.
It remains to be seen how well it does on physical ones, though.
Click to expand...

Hi.

Is it free tool?
If yes where I can download it?

I have similar problems, but I need to scan my disk and mark all bad sectors
and mark in addition few preceding- and following- good sectors wchich may
become bad in near future.

My problem is: during normal scandisk work some bad sectors was read
succesfully after few rerties (i guess: taken by diskcontroller or O.S.) and
they are NOT marked as bad.
Of course during normal operation (due to "Murphy laws") O.S. many times
encounter "almost bad sector" and wastes more than 5 secs on retries.
I need such a tool which scans surface and when encounters one (or two)
unsuccesful sector read - decides to mark this sector. (At this time I do
not care about data on that partition - I have backup)

best regards
 
Bazic said:
Hi.

Is it free tool?
Yup.


If yes where I can download it?
http://inet.uni2.dk/~svolaf/utilities.htm


I have similar problems, but I need to scan my disk and mark all bad sectors
and mark in addition few preceding- and following- good sectors which may
become bad in near future.
Click to expand...

If that disk was actually to be deteriorating that way you don't even want to
do that.
 
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