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Microsoft Windows NT Build 511 (DDK SDK) 11-01-1993

DOSIOCTL

This sample demonstrates the simulation of DOS function calls under NT.
Specifically, it shows how a DOS driver and VDD can tranlate DOS OPEN's,
CLOSE's and IOCTL's to the Win32 calls CreateFile(), CloseHandle() and
DeviceIoControl().

This 4 modules that make up this sample are listed below:

    DOSAPP      - DOS Application
    DOSDRVR     - DOS Device Driver
    VDD         - NT Virtual Device Driver
    KRLNDRVR    - NT Kernel Device Driver

These four modules work together to illustrate the basic communication
mechanisms that exist for each component.  When these components are
properly installed, running the DOS application will cause the following
chain of events to occur:


  1) DOSAPP issues an IOCTL Read.

  2) DOSDRV passes the call and buffer pointer to the VDD with the
     DispatchCall() function.

  3) VDD passes the buffer pointer from DOSDRV to KRNLDRVR with
     the Win32 DeviceIoControl() function.

  4) KRNLDRVR responds to the IOCTL with static information.

  5) The chain returns, and DOSAPP displays the information.


When the DOS application is run, it should produce the following line:

IOCTL Read returns: 12345678

The significance of this output is that the value x'12345678' is
defined only in the NT kernel driver. The sole purpose of the other
components is to deliver this single piece of data from the NT
driver to the DOS application.


Installing and Running this sample
----------------------------------

KRNLDRVR
--------

You can use Regedt32 to create a SERVICES entry for
the krnldrvr driver. Create a key under:

    HKEY_LOCAL_MACHINE\CurrentControlSet\Services\KRNLDRVR

with the following values:

    ErrorControl:DWORD 1
    Start:DWORD 3

Copy the KRNLDRVR.SYS created by the build process to the NT
SYSTEM32\DRIVERS directory. From and administrator account on
the machine, issue:

    NET START KRNLDRVR

Starting the driver manually in this manner can be beneficial
during the coding and testing phase of creating your own driver.


VDD
---

Because the DOS driver explicitly loads the VDD with a RegisterModule(),
the VDD.DLL file produced by the build process need only be available
in the search path.

DOSDRVR
-------

The DOS driver can be loaded by adding a "device=" line in the CONFIG.NT
file in the SYSTEM32 directory.


DOSAPP
------

The DOSAPP may simply be executed from any directory.

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