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Article ID: 121543 - Last Review: February 28, 2014 - Revision: 4.0

This article was previously published under Q121543
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This article outlines how to set up for remote debugging.

More information

To set up to remotely debug another computer, do the following:
  • Remove the System, Hidden, & ReadOnly attributes of the BOOT.INI file and append the following strings to the boot line:
    For example:
    [operating systems]
    multi(0)...partition(1)\NT="WinNT/S Ver:3.5" /DEBUGPORT=COM1
  • Run Terminal against the above Com Port with the debug modem attached and enter the modem commands which set the following:
         Function                              USRobotics
         Set back to Factory Defaults:         AT&F
         Disable Transmit Data Flow Control:   AT&H0
         Disable Receive Data Flow Control:    AT&I0
         Disable Data Compression:             AT&K0
         Disable Error Control:                AT&M0
         Auto Answer On:                       ATS0=1
         Disable Reset Modem on loss of DTR:   AT&D0
         Write to NVRAM:                       AT&W
  • Determine the base build of the remote computer (using WinMSD, WinVer),

    511, 528, 807

    and copy the corresponding debug files from the base build:

    <Compact Disc>\Support\Debug\<platformType>\*.* files to a
    <localDebug>\ directory and the corresponding Kernel & Hal *.DBG
    files from
    <Compact Disc>\Support\Debug\<platformType>\Symbols\EXE and
    <Compact Disc>\Support\Debug\<platformType>\Symbols\DLL respectively.

    For example:

    XCOPY E:\Support\Debug\i386\*.* C:\WinNT\Debug
    XCOPY E:\Support\Debug\i386\Symbols\EXE\NTKRNLMP.DBG ...
    ... C:\WinNT\Debug\Symbols\EXE /s /e
    XCOPY E:\Support\Debug\i386\Symbols\EXE\NTOSKRNL.DBG ...
    ... C:\WinNT\Debug\Symbols\EXE /s /e
    XCOPY E:\Support\Debug\i386\Symbols\DLL\HAL*.* ...
    ... C:\WinNT\Debug\Symbols\DLL /s /e

    where drive E: is the CD-ROM drive.

    NOTE: Using different (debugger 807 <-> target 528) kernel debuggers may prevent debuggers from "Sync"-ing.
  • Determine the Service Pack (SP) version (using WinMSD, WinVer),

    SP1, SP2, SP2b

    and copy the SP Symbols tree to the <localSymbols> directory. For more information on the SP Symbols tree, contact Microsoft Product Support Services (Enterprise Technical Support).
For example:
XCOPY <Source SP Symbols path> C:\WinNT\Debug\Symbols /s /e
  • Determine what Hotfixes, if any, have been installed,

    Prb18756, Bug18756

    and copy the Hotfix Symbols tree to <localSymbols\<dir>\. For more information on the Hotfix Symbols tree, contact Microsoft Product Support Services (Enterprise Technical Support).
For example:
XCOPY http://hotfix (http://hotfix)
  • Determine if you are using the Microsoft or third-party MP Kernel. If it is Microsoft's MP Kernel, then from <localSymbols>\EXE, copy NTKRNLMP.DBG to NTOSKRNL.DBG. If it is a third-party MP Kernel, obtain a copy of the symbols and copy it into your <localSymbols>\EXE\NTOSKRNL.DBG.
  • Determine if you are using the Microsoft Windows NT HAL or a third-party HAL. If it is a Microsoft Windows NT HAL, but not the standard ISA/EISA HAL, then from <localSymbols>\DLL, copy the appropriate HAL*.DBG to HAL.DBG. If it is a third-party HAL, obtain a copy of the symbols and copy it into your <localSymbols>\DLL\HAL.DBG.
  • Connect the modem to the remote debug target computer using the port from above and reboot the target computer.
  • Go to the <localDebug> directory and run the following REMDBG.BAT file:
          REM Modem String to Disable Flow Control and Compression
          ECHO "UsRobotics Modem string = AT&H0&I0&K0&M0"
          REM Environment Variables:
          REM Specify which com port to use. (Default = com1)
          set _NT_DEBUG_PORT=com1
          REM Specify symbol image path. (Default = x: * NO trailing
             backslash *)
          set _NT_SYMBOL_PATH=%2\Symbols
          REM Specify second symbol image path to be searched after the above.
          set _NT_ALT_SYMBOL_PATH=%3\Symbols
          REM Specify the baud rate used by debugging serial port.
             (Default = 19200)
          set _NT_DEBUG_BAUD_RATE=9600
          REM If specified, output will be APPENDed to this file.
          REM If specified, output will be written to this file from offset 0.
          REM set _NT_DEBUG_CACHE_SIZE=x
          remote /s "%1kd -m %4 %5 %6 %7 %8 %9" debug
          REM Usage: *kd [-?] [-v] [-m] [-r] [-n] [-b] [-x] [[-l
          SymbolFile] [KrnlName]
          REM     where:
          REM             -v      Verbose mode
          REM             -?      Display this help
          REM             -n      No Lazy symbol loading
          REM             -m      Use modem controls
          REM             -b      Break into kernel
          REM                    -c          Resync on Connect
          REM Control Keys:
          REM     . <Ctrl-C> Break into kernel
          REM       <Ctrl-B><Enter> Quit debugger
          REM     . <Ctrl-R><Enter> Resynchronize target and host
          REM     . <Ctrl-V><Enter> Toggle Verbose mode
          REM     . <Ctrl-D><Enter> Display debugger debugging information
       through the following command:
       [u:\winnt\debug] remdbg <kd> <localSymbols> <baseBuildpath> <addOptions>
                                 ^        ^             ^              ^
       Kernel Debugger to use ---+        |             |              |
          Example: i386 | MIPS | Alpha    |             |              |
                                          |             |              |
       localSymbols without Symbols name -+             |              |
          Example: c:\winnt\debug                       |              |
                                                        |              |
       baseBuild (UNC) without Symbols name ------------+              |
          Example: <Symbols server>\528\i386                           |
       Additional Debug Options ---------------------------------------+
          Example: -b (Break In on Connect) -c (Resync on Connect)
Contact Microsoft Product Support Services (Enterprise Technical Support) for more information on the <Symbols server>.


remdbg i386 u:\winnt\debug <Symbols server>\528\i386 -b
"UsRobotics Modem string = AT&H0&I0&K0&M0"

***********     REMOTE    ************
***********     SERVER    ************
To Connect: Remote /C MARCM.PORT debug

Microsoft(R) Windows NT Kernel Debugger
Version 1.00
(C) 1991 Microsoft Corp.

Symbol search path is: u:\winnt\debug\Symbols;.;
KD: ntoskrnl.exe image based at 80100000
KD: Preloading kernel symbols from u:\winnt\debug\Symbols\exe\ntoskrnl.DBG.
KD: waiting to connect...
KD: No carrier detect - in terminal mode

>From here, paste in the above Modem String and wait for the modem to return OK. Then enter the ATDT<Phone number> of the remote target computer as below: AT&H0&I0&K0&M0

ATDT9,<Phone number>
ATDT9,<Phone number>

KD: Carrier detect - returning to debugger
^R \\ Resync's the debuggers
KD: Kernel Debugger connection established. (Initial Breakpoint requested)
8015e109 cc int 3

Applies to
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Advanced Server 3.1
kbnosurvey kbarchive kbinfo KB121543
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