Booting from a RAMDISK image

Hi,
I used the RamDisk sample driver in the DDK and I was able
to use the Disk Administrator to create a partition and
format the RamDisk. My goal is to copy an NT bootable
image to the RamDisk and save the image. This image would
be downloaded to a reserved RAM before the system is
started. The BIOS (after hooking INT 13h) should access
this image as a bootable disk. Currently the RamDisk
driver formats the RamDisk as non bootable. Is it possible
to create a bootable image using the RAM DISK driver with
some modification? How NT determines the offset that it
passes to the driver? Does it use the drive geometry that
was provided by the driver to calculate this offset? If so
what is the “equation” in terms of the CHS parameters?

Thanks in advance,

Daniel

Maxim
Fri Aug 01 19:55:31 CDT 2003

You must write your own RAM disk driver (better as a SCSI miniport), and
pass the physical address there. Then map it by MmMapIoSpace and access.

NT's storage stack does not use the CHS values, they are used only inside
the ATA stack. Nevertheless, the Disk Managment UI seems to need this - I had a
bug with a SCSI disk emulator which did not show its full size in the Disk
Management till we added a MODE SENSE command support for a CHS values page
(rigid geometry IIRC).

Max

"Daniel" <daniel__steve@hotmail.com> wrote in message
news:051d01c3587d$25eb26b0$a101280a@phx.gbl...
> Hi,
> I used the RamDisk sample driver in the DDK and I was able
> to use the Disk Administrator to create a partition and
> format the RamDisk. My goal is to copy an NT bootable
> image to the RamDisk and save the image. This image would
> be downloaded to a reserved RAM before the system is
> started. The BIOS (after hooking INT 13h) should access
> this image as a bootable disk. Currently the RamDisk
> driver formats the RamDisk as non bootable. Is it possible
> to create a bootable image using the RAM DISK driver with
> some modification? How NT determines the offset that it
> passes to the driver? Does it use the drive geometry that
> was provided by the driver to calculate this offset? If so
> what is the &#8220;equation&#8221; in terms of the CHS parameters?
>
> Thanks in advance,
>
> Daniel
>

Daniel
Mon Aug 04 14:14:09 CDT 2003

Hi,

Thanks for your response.
Is there a sample driver in the DDK that I can start with?
Is the ATDISK a good start? If there is a sample driver,
Does it require a mojar modification?

Thanks,
Daniel




>-----Original Message-----
> You must write your own RAM disk driver (better as a
SCSI miniport), and
>pass the physical address there. Then map it by
MmMapIoSpace and access.
>
> NT's storage stack does not use the CHS values, they
are used only inside
>the ATA stack. Nevertheless, the Disk Managment UI seems
to need this - I had a
>bug with a SCSI disk emulator which did not show its full
size in the Disk
>Management till we added a MODE SENSE command support for
a CHS values page
>(rigid geometry IIRC).
>
> Max
>
>"Daniel" <daniel__steve@hotmail.com> wrote in message
>news:051d01c3587d$25eb26b0$a101280a@phx.gbl...
>> Hi,
>> I used the RamDisk sample driver in the DDK and I was
able
>> to use the Disk Administrator to create a partition and
>> format the RamDisk. My goal is to copy an NT bootable
>> image to the RamDisk and save the image. This image
would
>> be downloaded to a reserved RAM before the system is
>> started. The BIOS (after hooking INT 13h) should access
>> this image as a bootable disk. Currently the RamDisk
>> driver formats the RamDisk as non bootable. Is it
possible
>> to create a bootable image using the RAM DISK driver
with
>> some modification? How NT determines the offset that it
>> passes to the driver? Does it use the drive geometry
that
>> was provided by the driver to calculate this offset? If
so
>> what is the &#8220;equation&#8221; in terms of the CHS parameters?
>>
>> Thanks in advance,
>>
>> Daniel
>>
>
>
>.
>

Maxim
Tue Aug 05 23:17:13 CDT 2003

> Is there a sample driver in the DDK that I can start with?
> Is the ATDISK a good start? If there is a sample driver,

NT4's ATAPI miniport is a good starting point.

Max

Karan
Wed Aug 06 22:17:52 CDT 2003


"Daniel Steve" <daniel__steve@hotmail.com> wrote in message
|
| Hi,
|=20
| Thanks for your response.=20
| Is there a sample driver in the DDK that I can start with?
| Is the ATDISK a good start? If there is a sample driver,=20
| Does it require a mojar modification?
|=20

How about the ramdisk sample driver? - =
http://support.microsoft.com/default.aspx?scid=3Dkb;en-us;257405

--
karan

--=20
This posting is provided "AS IS" with no warranties, and confers no =
rights.