Observations of WinDbg 3.0 with Windows 2000

NTDEV
1

Hi All,

I find some interesting behavior of Windows 2000 when debugging using
WinDbg. I think these will be helpful for others, as I lost a day to figure
this out.

Firstly, when I make my Windows 2000 machine debug ready (by modifying
boot.ini), that particular COM port which I have indicated in my boot.ini
gets disabled upon booting ! i.e. the Device Manager shows that port with
insufficient resources.

I have downloaded the most recent version of the WinDBG (3.0) from
microsoft.com/ddk site. Here are my observations with the debugging :

The target machine is Windows 2000 checked build and host machine is
Windows 2000 free build. The debugger is on host machine. Both machines
also have Windows 98 and Windows NT 4.0 OSs (in separate partitions).

When I installed the WinDbg on W2K on host machine and tried to connect
it with W2K of the target machine (with proper null modem cable and
appropriate settings in boot.ini), the WinDbg failed to catch the
booting up of the target machine. i.e. the target machine booted up,
but no messages in debugger window.
With same configuration, I could connect when I used i386kd instead of
WinDbg !
(Note that the COM port used is still shown as disabled in Device Manager)

When I tried to connect with WinDbg on host machine and Windows NT 4.0
on target machine, it successfully connected.

When I installed Debugger on NT 4.0 of host machine, it could
successfully connect with NT 4.0 and Windows 2000 of the target machine.

Any comments/remedies are welcome.

Thanks and Regards,
Abhijit Mirajkar

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2

>-----Original Message-----

From: Abhijit Mirajkar
Sent: Wednesday, 1 August 2001 7:53

Firstly, when I make my Windows 2000 machine debug ready (by modifying
boot.ini), that particular COM port which I have indicated in my boot.ini
gets disabled upon booting ! i.e. the Device Manager shows that port with
insufficient resources.

That’s correct behaviour, since the hardware resources making up the
COM port have been taken by the kernel debugger, and are therefore not
available to the COM port driver.

–

Paul “TBBle” Hampson
Grand Poobah, Bubblesworth Pty Ltd (ABN: 51 095 284 361)
xxxxx@PObox.Com

If you love something, set it free.
If it comes back to you, it’s yours forever.
If it doesn’t, hunt it down and kill it.

Random signature generator 3.0 by Paul “TBBle” Hampson

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3

Based on the evidence you have given, I would say that you had the com port
settings wrong in the WinDBG session on your Win2K host. Make sure they are
identical to the com port settings in the session that worked on your NT4
host.

-----Original Message-----
From: Abhijit Mirajkar [mailto:xxxxx@controlnet.co.in]
Sent: Wednesday, August 01, 2001 2:53 AM
To: NT Developers Interest List
Subject: [ntdev] Observations of WinDbg 3.0 with Windows 2000

Hi All,

I find some interesting behavior of Windows 2000 when debugging using
WinDbg. I think these will be helpful for others, as I lost a day to figure
this out.

Firstly, when I make my Windows 2000 machine debug ready (by modifying
boot.ini), that particular COM port which I have indicated in my boot.ini
gets disabled upon booting ! i.e. the Device Manager shows that port with
insufficient resources.

I have downloaded the most recent version of the WinDBG (3.0) from
microsoft.com/ddk site. Here are my observations with the debugging :

The target machine is Windows 2000 checked build and host machine is
Windows 2000 free build. The debugger is on host machine. Both machines
also have Windows 98 and Windows NT 4.0 OSs (in separate partitions).

When I installed the WinDbg on W2K on host machine and tried to connect
it with W2K of the target machine (with proper null modem cable and
appropriate settings in boot.ini), the WinDbg failed to catch the
booting up of the target machine. i.e. the target machine booted up,
but no messages in debugger window.
With same configuration, I could connect when I used i386kd instead of
WinDbg !
(Note that the COM port used is still shown as disabled in Device Manager)

When I tried to connect with WinDbg on host machine and Windows NT 4.0
on target machine, it successfully connected.

When I installed Debugger on NT 4.0 of host machine, it could
successfully connect with NT 4.0 and Windows 2000 of the target machine.

Any comments/remedies are welcome.

Thanks and Regards,
Abhijit Mirajkar

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