Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

[Guest Franc Zabkar]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

On Mon, 17 Mar 2008 01:26:09 -0400, "MEB" <meb@not here@hotmail.com>

put finger to keyboard and composed:

>"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

>news:lfmrt31gsn197oq233venjp258m04h2okj@4ax.com...

>| On Sun, 16 Mar 2008 02:49:15 -0400, "MEB" <meb@not here@hotmail.com>

>| put finger to keyboard and composed:

>|

>| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

>| >news:fpsot31cqbpk9hqca2pljhbums5dveqg99@4ax.com...

>|

>| >| On Fri, 14 Mar 2008 05:35:07 -0400, "MEB" <meb@not here@hotmail.com>

>| >| put finger to keyboard and composed:

>| >|

>| >| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

>| >| >news:ia9jt35o6fi1rrjkqfvm3p0cuskn84aohj@4ax.com...

>|

>| >| >| ... I now tried

>| >| >| FIXMBR. This command warned me that the MBR contained unknown or

>| >| >| damaged code, so I went ahead and allowed it to refresh the code. It

>| >| >| reported success but when I ran FIXMBR a second time, it still

>| >| >| complained of unknown or damaged code.

>| >| >

>| >| > First I would question whether you cold rebooted between the two

>FIXMBR

>| >| >[FIXMBR {ugh} which I found to be questionable when using] trys.

>| >|

>| >| I don't think I did.

>| >

>| > Kind of like fdisking a drive, gotta reboot.

>|

>| I can see why you would need to reboot before any newly created

>| partitions and logical drives would be detected, but I can't see why

>| you would need to do the same after refreshing the code in the MBR.

>| AFAIK, the MBR code doesn't remain in RAM after booting ...

>| - Franc Zabkar

>

> And how does it do this when it has already been accessed upon bootup, and

>found as faulty. The disk couldn't be accessed properly, so how can it now,

>when the code and jumps were wrong to start with and have not been refreshed

>yet.. You could see it with an editor, but the BIOS has already transferred

>activity elsewhere [particularly in NT].

>

> Are you indicating that there were no errors when attempting to access the

>hard disk after doing so?

>______

>* MEB

>http://peoplescounsel.orgfree.com

 

I don't think any question regarding the integrity of the code in the

MBR is of any consequence because I booted to the recovery console of

an XP CD. I'm guessing that FIXMBR should work in much the same way as

FDISK /MBR in Win9x/DOS, ie it should refresh the code in the first

physical sector of the HD, regardless of what is already there. FIXMBR

appears to go one step further by warning the user if the MBR code

appears to be foreign or damaged, but that's the only difference,

AFAICT. FDISK and DISKPART appear to perform similar functions when

accessed via their interactive menus. I would think that FDISK,

FIXMBR, and DISKPART would always be aware of any changes they

themselves have made to the MBR and partition table, without the

necessity of a reboot. A reboot would only be necessary to allow the

*operating system* to become aware of the same changes. During a

reboot, the OS would enumerate the logical drives by looking at the

partition table. Thereafter, I can't see that the OS would need to

consult the partition table again. I would think that if you deleted

the partition table while the OS was running, then the OS would

continue to run with the same drive parameters that it had discovered

at bootup ... until the next bootup.

 

The suggestion that FIXMBR requires a reboot before it becomes aware

of the changes it has made would mean that it would be consulting some

stale memory cache. This makes no sense because the first time you run

FIXMBR there is no MBR code in RAM (it has been flushed early in the

boot process). So if FIXMBR consults the HD the first time it is

executed, then why wouldn't it do the same the second time it is run?

 

This is what I see when I execute ...

 

MEM /D /P

 

.... from a DOS prompt in Win98SE:

 

=====================================================================

Conventional Memory Detail:

 

Segment Total Name Type

------- ---------------- ----------- --------

00000 1,024 (1K) Interrupt Vector

00040 256 (0K) ROM Communication

Area

00050 512 (1K) DOS Communication

Area

00070 1,424 (1K) IO System Data

CON System Device Driver

AUX System Device Driver

PRN System Device Driver

CLOCK$ System Device Driver

A: - D: System Device Driver

 

<snip>

 

=====================================================================

 

Win9x/DOS has loaded "System Device Drivers" for each of my logical

drives (A: - D:). I suspect that if I were to use FDISK to edit the

partition table, and then re-run the above MEM command without first

rebooting, nothing would change. I'm betting you would still be able

to write new files to the C: drive without loss of data ... provided

that you restored the original partition table prior to rebooting. But

that's only a guess - I don't have a test machine to try this.

 

- Franc Zabkar

--

Please remove one 'i' from my address when replying by email.

[Guest MEB]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

 

 

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

news:53i0u3117q5lkhua2j7m3jpp7urjpr46ic@4ax.com...

| On Mon, 17 Mar 2008 01:26:09 -0400, "MEB" <meb@not here@hotmail.com>

| put finger to keyboard and composed:

|

| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

| >news:lfmrt31gsn197oq233venjp258m04h2okj@4ax.com...

| >| On Sun, 16 Mar 2008 02:49:15 -0400, "MEB" <meb@not here@hotmail.com>

| >| put finger to keyboard and composed:

| >|

| >| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

| >| >news:fpsot31cqbpk9hqca2pljhbums5dveqg99@4ax.com...

| >|

| >| >| On Fri, 14 Mar 2008 05:35:07 -0400, "MEB" <meb@not here@hotmail.com>

| >| >| put finger to keyboard and composed:

| >| >|

| >| >| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

| >| >| >news:ia9jt35o6fi1rrjkqfvm3p0cuskn84aohj@4ax.com...

| >|

| >| >| >| ... I now tried

| >| >| >| FIXMBR. This command warned me that the MBR contained unknown or

| >| >| >| damaged code, so I went ahead and allowed it to refresh the code.

It

| >| >| >| reported success but when I ran FIXMBR a second time, it still

| >| >| >| complained of unknown or damaged code.

| >| >| >

| >| >| > First I would question whether you cold rebooted between the two

| >FIXMBR

| >| >| >[FIXMBR {ugh} which I found to be questionable when using] trys.

| >| >|

| >| >| I don't think I did.

| >| >

| >| > Kind of like fdisking a drive, gotta reboot.

| >|

| >| I can see why you would need to reboot before any newly created

| >| partitions and logical drives would be detected, but I can't see why

| >| you would need to do the same after refreshing the code in the MBR.

| >| AFAIK, the MBR code doesn't remain in RAM after booting ...

|

| >| - Franc Zabkar

| >

| > And how does it do this when it has already been accessed upon bootup,

and

| >found as faulty. The disk couldn't be accessed properly, so how can it

now,

| >when the code and jumps were wrong to start with and have not been

refreshed

| >yet.. You could see it with an editor, but the BIOS has already

transferred

| >activity elsewhere [particularly in NT].

| >

| > Are you indicating that there were no errors when attempting to access

the

| >hard disk after doing so?

| >______

| >* MEB

| >http://peoplescounsel.orgfree.com

|

| I don't think any question regarding the integrity of the code in the

| MBR is of any consequence because I booted to the recovery console of

| an XP CD. I'm guessing that FIXMBR should work in much the same way as

| FDISK /MBR in Win9x/DOS, ie it should refresh the code in the first

| physical sector of the HD, regardless of what is already there. FIXMBR

| appears to go one step further by warning the user if the MBR code

| appears to be foreign or damaged, but that's the only difference,

| AFAICT. FDISK and DISKPART appear to perform similar functions when

| accessed via their interactive menus. I would think that FDISK,

| FIXMBR, and DISKPART would always be aware of any changes they

| themselves have made to the MBR and partition table, without the

| necessity of a reboot. A reboot would only be necessary to allow the

| *operating system* to become aware of the same changes. During a

| reboot, the OS would enumerate the logical drives by looking at the

| partition table. Thereafter, I can't see that the OS would need to

| consult the partition table again. I would think that if you deleted

| the partition table while the OS was running, then the OS would

| continue to run with the same drive parameters that it had discovered

| at bootup ... until the next bootup.

|

| The suggestion that FIXMBR requires a reboot before it becomes aware

| of the changes it has made would mean that it would be consulting some

| stale memory cache. This makes no sense because the first time you run

| FIXMBR there is no MBR code in RAM (it has been flushed early in the

| boot process). So if FIXMBR consults the HD the first time it is

| executed, then why wouldn't it do the same the second time it is run?

|

| This is what I see when I execute ...

|

| MEM /D /P

|

| ... from a DOS prompt in Win98SE:

|

| =====================================================================

| Conventional Memory Detail:

|

| Segment Total Name Type

| ------- ---------------- ----------- --------

| 00000 1,024 (1K) Interrupt Vector

| 00040 256 (0K) ROM Communication

| Area

| 00050 512 (1K) DOS Communication

| Area

| 00070 1,424 (1K) IO System Data

| CON System Device Driver

| AUX System Device Driver

| PRN System Device Driver

| CLOCK$ System Device Driver

| A: - D: System Device Driver

|

| <snip>

|

| =====================================================================

|

| Win9x/DOS has loaded "System Device Drivers" for each of my logical

| drives (A: - D:). I suspect that if I were to use FDISK to edit the

| partition table, and then re-run the above MEM command without first

| rebooting, nothing would change. I'm betting you would still be able

| to write new files to the C: drive without loss of data ... provided

| that you restored the original partition table prior to rebooting. But

| that's only a guess - I don't have a test machine to try this.

|

| - Franc Zabkar

| --

| Please remove one 'i' from my address when replying by email.

 

You're running the Recovery Console from NT, NOT from DOS.

NT handles disk access in a different form... a common mistake made by *DOS

users* is to think NT works like DOS does.

I think we already did this before, to a point, in those prior XP and hard

drive discussions.

 

--

MEB

http://peoplescounsel.orgfree.com

--

_________

[Guest Franc Zabkar]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

On Sun, 16 Mar 2008 02:49:15 -0400, "MEB" <meb@not here@hotmail.com>

put finger to keyboard and composed:

>"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

>news:fpsot31cqbpk9hqca2pljhbums5dveqg99@4ax.com...

>| >| ... I now tried

>| >| FIXMBR. This command warned me that the MBR contained unknown or

>| >| damaged code, so I went ahead and allowed it to refresh the code. It

>| >| reported success but when I ran FIXMBR a second time, it still

>| >| complained of unknown or damaged code.

>| >

>| > First I would question whether you cold rebooted between the two FIXMBR

>| >[FIXMBR {ugh} which I found to be questionable when using] trys.

>|

>| I don't think I did.

>

> Kind of like fdisking a drive, gotta reboot.

 

The following MSKB article identifies a FIXMBR bug in the Win2K

recovery console, but I wonder if it applies to WinXP Home as well.

 

Error Message When You Run fixmbr Command:

http://support.microsoft.com/kb/266745/

 

SYMPTOMS

 

When you attempt to run the fixmbr command in the Microsoft Windows

2000 recovery console, your computer system may display the following

error message:

 

This computer appears to have a non-standard or invalid master boot

record. FIXMBR may damage your partition tables if you proceed. This

could cause all the partitions on the current hard disk to become

inaccessible. If you are not having problems accessing your drive, do

not continue. Are you sure you want to write a new MBR?

 

RESOLUTION

 

Ignore the error message described in the "Symptoms" section of this

article. The fixmbr command can safely rewrite the MBR.

 

STATUS

 

Microsoft has confirmed that this is a problem in the Microsoft

products that are listed at the beginning of this article.

 

MORE INFORMATION

 

The fixmbr command causes this error message to be displayed on your

computer system whenever you run the command, regardless of the state

of the Master Boot Record (MBR).

 

- Franc Zabkar

--

Please remove one 'i' from my address when replying by email.

[Guest Franc Zabkar]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

On Mon, 17 Mar 2008 01:10:37 -0400, "MEB" <meb@not here@hotmail.com>

> I sent you, from the master site address, some zipped *readable text* of a

>few files from XP PRO which might be of interest you [though you probably

>already did]. Look at the command sequences, messages, and other. At

>minimum, they give some search strings to work from when playing around in

>XP and a hexeditor.

>

>* MEB

>http://peoplescounsel.orgfree.com

 

I got it, thanks, although I'm not sure what to do with it because I

no longer have any XP boxes to play with.

 

FWIW, here are various boot sector templates that I extracted from

Autochk.exe, and the MBR template that I found inside Diskpart.exe:

 

http://www.users.on.net/~fzabkar/XP_Boot/XP_Boot.zip (11KB)

 

- Franc Zabkar

--

Please remove one 'i' from my address when replying by email.

[Guest MEB]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

Thanks Franc.

 

An FWIW: download the XP Startup disks if you want copies of what gets

loaded to start the Recovery Console.

 

--

MEB

http://peoplescounsel.orgfree.com

--

_________

 

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

news:8g11u397kb5jf609mns0ggssd4aqtp3efl@4ax.com...

| On Mon, 17 Mar 2008 01:10:37 -0400, "MEB" <meb@not here@hotmail.com>

|

| > I sent you, from the master site address, some zipped *readable text* of

a

| >few files from XP PRO which might be of interest you [though you probably

| >already did]. Look at the command sequences, messages, and other. At

| >minimum, they give some search strings to work from when playing around

in

| >XP and a hexeditor.

| >

| >* MEB

| >http://peoplescounsel.orgfree.com

|

| I got it, thanks, although I'm not sure what to do with it because I

| no longer have any XP boxes to play with.

|

| FWIW, here are various boot sector templates that I extracted from

| Autochk.exe, and the MBR template that I found inside Diskpart.exe:

|

| http://www.users.on.net/~fzabkar/XP_Boot/XP_Boot.zip (11KB)

|

| - Franc Zabkar

| --

| Please remove one 'i' from my address when replying by email.

[Guest MEB]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

 

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

news:ds01u3pu2iebbaubb9ifbvlm1sc5lgmtng@4ax.com...

| On Sun, 16 Mar 2008 02:49:15 -0400, "MEB" <meb@not here@hotmail.com>

| put finger to keyboard and composed:

|

| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

| >news:fpsot31cqbpk9hqca2pljhbums5dveqg99@4ax.com...

|

| >| >| ... I now tried

| >| >| FIXMBR. This command warned me that the MBR contained unknown or

| >| >| damaged code, so I went ahead and allowed it to refresh the code. It

| >| >| reported success but when I ran FIXMBR a second time, it still

| >| >| complained of unknown or damaged code.

| >| >

| >| > First I would question whether you cold rebooted between the two

FIXMBR

| >| >[FIXMBR {ugh} which I found to be questionable when using] trys.

| >|

| >| I don't think I did.

| >

| > Kind of like fdisking a drive, gotta reboot.

|

| The following MSKB article identifies a FIXMBR bug in the Win2K

| recovery console, but I wonder if it applies to WinXP Home as well.

|

| Error Message When You Run fixmbr Command:

| http://support.microsoft.com/kb/266745/

|

| SYMPTOMS

|

| When you attempt to run the fixmbr command in the Microsoft Windows

| 2000 recovery console, your computer system may display the following

| error message:

|

| This computer appears to have a non-standard or invalid master boot

| record. FIXMBR may damage your partition tables if you proceed. This

| could cause all the partitions on the current hard disk to become

| inaccessible. If you are not having problems accessing your drive, do

| not continue. Are you sure you want to write a new MBR?

|

| RESOLUTION

|

| Ignore the error message described in the "Symptoms" section of this

| article. The fixmbr command can safely rewrite the MBR.

|

| STATUS

|

| Microsoft has confirmed that this is a problem in the Microsoft

| products that are listed at the beginning of this article.

|

| MORE INFORMATION

|

| The fixmbr command causes this error message to be displayed on your

| computer system whenever you run the command, regardless of the state

| of the Master Boot Record (MBR).

|

| - Franc Zabkar

| --

| Please remove one 'i' from my address when replying by email.

 

Yeah, I remember that one now, likely part of the reason I asked what

versions you ran, IIRC, there was an update for XP [or maybe included in SP1

or the DK] that was supposed to fix some of the old errors... another memory

sloshing around in the brain..

--

MEB

http://peoplescounsel.orgfree.com

--

_________

[Guest Franc Zabkar]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

On Wed, 19 Mar 2008 01:15:51 -0400, "MEB" <meb@not here@hotmail.com>

put finger to keyboard and composed:

>"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

>news:ds01u3pu2iebbaubb9ifbvlm1sc5lgmtng@4ax.com...

>| The following MSKB article identifies a FIXMBR bug in the Win2K

>| recovery console, but I wonder if it applies to WinXP Home as well.

>|

>| Error Message When You Run fixmbr Command:

>| http://support.microsoft.com/kb/266745/

>|

>| SYMPTOMS

>|

>| When you attempt to run the fixmbr command in the Microsoft Windows

>| 2000 recovery console, your computer system may display the following

>| error message:

>|

>| This computer appears to have a non-standard or invalid master boot

>| record.

>| MORE INFORMATION

>|

>| The fixmbr command causes this error message to be displayed on your

>| computer system whenever you run the command, regardless of the state

>| of the Master Boot Record (MBR).

>|

>| - Franc Zabkar

>

> Yeah, I remember that one now, likely part of the reason I asked what

>versions you ran, IIRC, there was an update for XP [or maybe included in SP1

>or the DK] that was supposed to fix some of the old errors... another memory

>sloshing around in the brain..

>--

>MEB

>http://peoplescounsel.orgfree.com

 

How do you apply a service pack to the recovery console on a pressed

CD? ;-|

 

- Franc Zabkar

--

Please remove one 'i' from my address when replying by email.

[Guest MEB]

Re: Quirks in Scandisk, Chkdsk, Fixmbr, Fixboot

 

 

 

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

news:fks2u3pfpb5g4n2mtpjp3d54r0qemlj0ha@4ax.com...

| On Wed, 19 Mar 2008 01:15:51 -0400, "MEB" <meb@not here@hotmail.com>

| put finger to keyboard and composed:

|

| >"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message

| >news:ds01u3pu2iebbaubb9ifbvlm1sc5lgmtng@4ax.com...

|

| >| The following MSKB article identifies a FIXMBR bug in the Win2K

| >| recovery console, but I wonder if it applies to WinXP Home as well.

| >|

| >| Error Message When You Run fixmbr Command:

| >| http://support.microsoft.com/kb/266745/

| >|

| >| SYMPTOMS

| >|

| >| When you attempt to run the fixmbr command in the Microsoft Windows

| >| 2000 recovery console, your computer system may display the following

| >| error message:

| >|

| >| This computer appears to have a non-standard or invalid master boot

| >| record.

|

| >| MORE INFORMATION

| >|

| >| The fixmbr command causes this error message to be displayed on your

| >| computer system whenever you run the command, regardless of the state

| >| of the Master Boot Record (MBR).

| >|

| >| - Franc Zabkar

| >

| > Yeah, I remember that one now, likely part of the reason I asked what

| >versions you ran, IIRC, there was an update for XP [or maybe included in

SP1

| >or the DK] that was supposed to fix some of the old errors... another

memory

| >sloshing around in the brain..

| >--

| >MEB

| >http://peoplescounsel.orgfree.com

|

| How do you apply a service pack to the recovery console on a pressed

| CD? ;-|

|

| - Franc Zabkar

| --

| Please remove one 'i' from my address when replying by email.

 

HAHAHA, good one. You don't, but the technique is called slip streaming for

the disk you then create.

 

http://support.microsoft.com/kb/828930/ - How to integrate software updates

into your Windows Installation source files

http://support.microsoft.com/kb/900910/en-us

..

You can modify the startup disks.

 

--

MEB

http://peoplescounsel.orgfree.com

--

_________