The Virtual Drive Issue

For starters, this is going to sound highly lame, but
how do i post messages to the same thread, i couldn’t
fine a link to it anywhere…and yes, i did try to
read the FAQs

This is indeed a student project. Our very crude
design does in fact involve simply “hiding” the file
fragments on the other drives. OK, let

me explain our design. We were thinking on the lines
of maintaing the directory listing for the virtual E:
on say c:, in the form of files

and folders all of size 0 bytes, ie every time a
file/folder is copied on to E:, we create a similar
file/folder entry in say “C:\MountThis”.

We then mount C:\MountThis using the DOS “SUBST”, and
make the E: accessible in Explorer. This because we
dont know of any easier way to

mount a virtual drive and not worry about maintaining
the FS entries for E:. Internally however the
file/folder contents may be split accross

C: and D:, and our driver needs to maintain a table of
actual locations and sizes of the fragments. Moreover,
we want to let the user access

these fragments as a whole from E:. For eg, if I had a
200MB video clip “Movie” stored as “Part1” on C: and
“Part2” on D:, I still want to

let the user play the “Movie” file from E: in Windows
Media Player. All reads have to be trapped and
redirected to “Part1” and then “Part2”

as required.

Is this achievalbe?
What sort of a driver would I need?
Is the pseudoFS possible in this case?
Any other suggestions?

Thanks,
Gaurav


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You can redirect sector level request to files by having a class
driver if you just concern about storage virtualization. Check the
FileDisk sample at http://www.acc.umu.se/~bosse/.

You need a pseudo file system for file level redirection.

Regards
Bala

On Thu, 10 Feb 2005 21:52:31 -0800 (PST), Gaurav Gore
wrote:
> For starters, this is going to sound highly lame, but
> how do i post messages to the same thread, i couldn’t
> fine a link to it anywhere…and yes, i did try to
> read the FAQs
>
> This is indeed a student project. Our very crude
> design does in fact involve simply “hiding” the file
> fragments on the other drives. OK, let
>
> me explain our design. We were thinking on the lines
> of maintaing the directory listing for the virtual E:
> on say c:, in the form of files
>
> and folders all of size 0 bytes, ie every time a
> file/folder is copied on to E:, we create a similar
> file/folder entry in say “C:\MountThis”.
>
> We then mount C:\MountThis using the DOS “SUBST”, and
> make the E: accessible in Explorer. This because we
> dont know of any easier way to
>
> mount a virtual drive and not worry about maintaining
> the FS entries for E:. Internally however the
> file/folder contents may be split accross
>
> C: and D:, and our driver needs to maintain a table of
> actual locations and sizes of the fragments. Moreover,
> we want to let the user access
>
> these fragments as a whole from E:. For eg, if I had a
> 200MB video clip “Movie” stored as “Part1” on C: and
> “Part2” on D:, I still want to
>
> let the user play the “Movie” file from E: in Windows
> Media Player. All reads have to be trapped and
> redirected to “Part1” and then “Part2”
>
> as required.
>
> Is this achievalbe?
> What sort of a driver would I need?
> Is the pseudoFS possible in this case?
> Any other suggestions?
>
> Thanks,
> Gaurav
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
> —
> Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: xxxxx@gmail.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>

First, this isn’t what the OP was asking for. And second, please do not
point people to code that was stolen and illegally published under the GNU
license.


Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
Remove StopSpam from the email to reply

“Bala Durairaj” wrote in message news:xxxxx@ntfsd…
> You can redirect sector level request to files by having a class
> driver if you just concern about storage virtualization. Check the
> FileDisk sample at http://www.acc.umu.se/~bosse/.
>
> You need a pseudo file system for file level redirection.
>
> Regards
> Bala
>
> On Thu, 10 Feb 2005 21:52:31 -0800 (PST), Gaurav Gore
> wrote:
>> For starters, this is going to sound highly lame, but
>> how do i post messages to the same thread, i couldn’t
>> fine a link to it anywhere…and yes, i did try to
>> read the FAQs
>>
>> This is indeed a student project. Our very crude
>> design does in fact involve simply “hiding” the file
>> fragments on the other drives. OK, let
>>
>> me explain our design. We were thinking on the lines
>> of maintaing the directory listing for the virtual E:
>> on say c:, in the form of files
>>
>> and folders all of size 0 bytes, ie every time a
>> file/folder is copied on to E:, we create a similar
>> file/folder entry in say “C:\MountThis”.
>>
>> We then mount C:\MountThis using the DOS “SUBST”, and
>> make the E: accessible in Explorer. This because we
>> dont know of any easier way to
>>
>> mount a virtual drive and not worry about maintaining
>> the FS entries for E:. Internally however the
>> file/folder contents may be split accross
>>
>> C: and D:, and our driver needs to maintain a table of
>> actual locations and sizes of the fragments. Moreover,
>> we want to let the user access
>>
>> these fragments as a whole from E:. For eg, if I had a
>> 200MB video clip “Movie” stored as “Part1” on C: and
>> “Part2” on D:, I still want to
>>
>> let the user play the “Movie” file from E: in Windows
>> Media Player. All reads have to be trapped and
>> redirected to “Part1” and then “Part2”
>>
>> as required.
>>
>> Is this achievalbe?
>> What sort of a driver would I need?
>> Is the pseudoFS possible in this case?
>> Any other suggestions?
>>
>> Thanks,
>> Gaurav
>>
>> __________________________________________________
>> Do You Yahoo!?
>> Tired of spam? Yahoo! Mail has the best spam protection around
>> http://mail.yahoo.com
>>
>> —
>> Questions? First check the IFS FAQ at
>> https://www.osronline.com/article.cfm?id=17
>>
>> You are currently subscribed to ntfsd as: xxxxx@gmail.com
>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>

Gaurav Gore wrote:

For starters, this is going to sound highly lame, but
how do i post messages to the same thread, i couldn’t
fine a link to it anywhere…and yes, i did try to
read the FAQs

Yeah. If you’re reading the list via a newsreader, you reply to the
thread. If you’re reading the list via email, you reply to the email.
Can’t get much simpler than that, I think.

This is indeed a student project. Our very crude
design does in fact involve simply “hiding” the file
fragments on the other drives. OK, let
me explain our design. We were thinking on the lines
of maintaing the directory listing for the virtual E:
on say c:, in the form of files
and folders all of size 0 bytes, ie every time a
file/folder is copied on to E:, we create a similar
file/folder entry in say “C:\MountThis”.

We then mount C:\MountThis using the DOS “SUBST”, and
make the E: accessible in Explorer. This because we
dont know of any easier way to
mount a virtual drive and not worry about maintaining
the FS entries for E:. Internally however the
file/folder contents may be split accross
C: and D:, and our driver needs to maintain a table of
actual locations and sizes of the fragments. Moreover,
we want to let the user access
these fragments as a whole from E:. For eg, if I had a
200MB video clip “Movie” stored as “Part1” on C: and
“Part2” on D:, I still want to
let the user play the “Movie” file from E: in Windows
Media Player. All reads have to be trapped and
redirected to “Part1” and then “Part2”
as required.

Is this achievalbe?
What sort of a driver would I need?
Is the pseudoFS possible in this case?
Any other suggestions?

I’m STILL not sure I understand what you want to do (no, let me make
that "I’m SURE I still do not understand what you want to do). But I DO
know what I’d suggest a different project. Seriously.

Writing a file system with the IFS kit (you DID realize that you’d need
the Windows IFS Kit for ANY of this, not just the DDK, right?) is really
not for the faint of heart. And certainly not a group of undergrads who
don’t already know how to write Windows drivers and want to do it in two
months. Down the path you are talking about going, many fine engineers
– in fact, entire COMPANIES of engineers – have fallen.

Forget file systems for a summer project. Have the team develop a
driver for a nice USB-controlled Hello Kitty doll or something. Figure
out how to mount a video camera in its forehead and take high-speed data
from it without causing the system to come to its knees. Now THAT’s a
project some undergrads can do in a couple of months.

Peter
OSR

Hi!

Actually there is a way to achieve what I think you want to do without
having to develop a file system driver:

Build a (virtual) disk driver (similar to what someone else has
suggested), and create a program to prepare all necessary structures (for
FAT32: boot sector, FAT, directories) and then let your driver satisfy
read requests to your virtual volume by either reads to the prepared
structures and/or the real source files scattered around your computer.
That way you can generate virtual files of up to 4GB in size. Still there
is quite some work involved…

Cheers,
Michael Baudisch

[…]

> C: and D:, and our driver needs to maintain a table of
> actual locations and sizes of the fragments. Moreover,
> we want to let the user access
> these fragments as a whole from E:. For eg, if I had a
> 200MB video clip “Movie” stored as “Part1” on C: and
> “Part2” on D:, I still want to
> let the user play the “Movie” file from E: in Windows
> Media Player. All reads have to be trapped and
> redirected to “Part1” and then “Part2”
> as required.
>
> Is this achievalbe?
> What sort of a driver would I need?
> Is the pseudoFS possible in this case?
> Any other suggestions?
>

I’m STILL not sure I understand what you want to do (no, let me make
that "I’m SURE I still do not understand what you want to do). But I DO
know what I’d suggest a different project. Seriously.

Writing a file system with the IFS kit (you DID realize that you’d need
the Windows IFS Kit for ANY of this, not just the DDK, right?) is really
not for the faint of heart. And certainly not a group of undergrads who
don’t already know how to write Windows drivers and want to do it in two
months. Down the path you are talking about going, many fine engineers
– in fact, entire COMPANIES of engineers – have fallen.


Vogon International GmbH
http://www.vogon-international.com