dirty bit

[Nick Burns]

How do you unset the dirty bit for a drive. Chkdsk runs every boot up. I
have found how to set it, but not the reverse.

 

[cquirke (MVP Win9x)]

How do you unset the dirty bit for a drive. Chkdsk runs every boot up. I
have found how to set it, but not the reverse.

Don't shoot the messenger!

If the dirty bit is set on every startup, it means one of:

1) You and/or the PC aren't shutting down properly

Go forth, and sin no more. If PC's crashing, then troubleshoot and
fix that so that it stops crashing.

2) The PC doesn't really shut down properly

This was sometimes an issue with Win9x, that ATX power may cut after
data was fully sent to the HD, but before the HD had fully written the
data to the actual disk platters. The result; what looks like a
proper shutdown, yet data is still lost and thus the file system
appropriately remains flagged as "dirty" and to be checked.

3) Your HD is dying

The normal "dirty" bit is left set only if file operations were
interrupted, but there is another flag that is only set when access to
the HD phyically fails. This is a serious situation, as the HD may
fail and eat everything! The difference that you will see is that
when the system automatically checks the HD, it will go on to do a
full surface check that will take ages. Backup, prepare to swap HD.

4) ChkDsk is being explicitly launched

In this situation, the dirty bit may not be involved at all. Look for
ChkDsk, AutoChk, or shortcuts to these, either in Startup groups,
elsewhere in the startup axis, or as a logon or startup Task.

 

[Nick Burns]

Thanks for the reply.

Power went out when defrag was running and that started the glitch.

Drive is about 2 months old..

I use drive every day for video rendering for mega hours and never have
problems.

All my software including manufacture test show no errors.

All software says drive is dirty.

I have read loads of post about this problem with no fix.

MS tells how to set the bit, why not how to unset, or does know one know how
to do this, it's only one bit.

Is this bit part of the HD, the reg, or where is it. I do write assembly if
I know where to go...?

Thanks again.

 

[cquirke (MVP Win9x)]

Power went out when defrag was running and that started the glitch.
Drive is about 2 months old..

That sounds like possible physical damage - which the HD's firmware
and NTFS code may try to hide from you.

I use drive every day for video rendering for mega hours and never have
problems.

All my software including manufacture test show no errors.
All software says drive is dirty.

I'd look for SMART detail, e.g. with AIDA32; drive vendor's tools are
likely to take "you are dying" to mean "you aren't dead yet, so
everything's fine; no, we don't need to send you a replacemet".

If ChkDsk or anything else claims to have found bad sectors (or
clusters) but it's OK because they are fixed now, suspect the worst.

Is this bit part of the HD, the reg, or where is it. I do write assembly if
I know where to go...?

First thing is to see which bit it is. If it's simple "interrupted
file ops" then OK, force it; it will pop back if it has to. If it's
the "hey, I can't access the drive" bit, then nature's trying to tell
you something that's quite important.

The location of these bits is documented in FATxx, but I don't know
where from memory (it's in the front of the FAT). NTFS doesn't have a
FAT, so obviously they must be somewhere else there.

 

[Philip Herlihy]

A naive reply perhaps, but I cured this on a customer's machine by booting
into "safe mode with command prompt", and running scandisk from there.
Never saw it again.

--
####################
## PH, London
####################

 

[Nick Burns]

No check has detected any problem and I have used AIDA32 and drive vendors
tool.

The problem was not from a power out, it was when I started defrag and
decided to cancel. The drive light never went out so I did a restart and
chkdsk has run ever their after. I will just copy all from the e: to a
folder in c: and format e: To bad their is not a easier.

 

[Nick Burns]

I have run all forms of chkdsk and other utilities from run mode safemode
and the recovery console.