Just need an opinion

Hi all,

I have a project at hand which involves solving the
following problem.
Consider that I have a Disk Drive split into two
partitions C: and D:, each with say a 100MB of free
space. If in case I want to save a 200MB file to my
drive , I will not be able to do it (but, of course).
What I intend on doing is to split the 200MB file in
two parts and store the parts on C: and D:. Moreover,I
want to create a virtual drive say E:, from where the
user should be able to access the 200MB file as a
whole. I understand that this involves writing a FS
Filter to redirect I/O, but I am completely new to
writing drivers and dont understand the complexity of
this project. Is this sort of a thing manageable by a
team of 4 people (all engineering undergrads)who are
fairly good at picking up concepts and have 2 - 3
months at hand??? (Sorry about writing such a long
post!! and asking such a dumb question !!)We are
having a look at the DDK documentation currently.

Regards,
Gaurav


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Why would this be a file system filter driver? It sounds like this is
either a striping storage driver or some sort of hybrid file system
driver. I’d suggest the former (much simpler) or latter.

Either would be reasonable student projects. The first one is clearly
achievable, the latter would be more of a challenge.

Others on the list might have additional thoughts and insight as well.

Regards,

Tony

Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
http://www.osr.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Gaurav Gore
Sent: Thursday, February 10, 2005 2:20 PM
To: ntfsd redirect
Subject: [ntfsd] Just need an opinion

Hi all,

I have a project at hand which involves solving the
following problem.
Consider that I have a Disk Drive split into two
partitions C: and D:, each with say a 100MB of free
space. If in case I want to save a 200MB file to my
drive , I will not be able to do it (but, of course).
What I intend on doing is to split the 200MB file in
two parts and store the parts on C: and D:. Moreover,I
want to create a virtual drive say E:, from where the
user should be able to access the 200MB file as a
whole. I understand that this involves writing a FS
Filter to redirect I/O, but I am completely new to
writing drivers and dont understand the complexity of
this project. Is this sort of a thing manageable by a
team of 4 people (all engineering undergrads)who are
fairly good at picking up concepts and have 2 - 3
months at hand??? (Sorry about writing such a long
post!! and asking such a dumb question !!)We are
having a look at the DDK documentation currently.

Regards,
Gaurav


Do you Yahoo!?
Yahoo! Mail - 250MB free storage. Do more. Manage less.
http://info.mail.yahoo.com/mail_250


Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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Gaurav Gore wrote:

whole. I understand that this involves writing a FS
Filter to redirect I/O, but I am completely new to
writing drivers and dont understand the complexity of
this project. Is this sort of a thing manageable by a
team of 4 people (all engineering undergrads)who are
fairly good at picking up concepts and have 2 - 3
months at hand???

Is this a real project (in other words, a real product thing that really
had to work all the time, every time)? Or is this a student project??

Hmmmmm… Raises some interesting problems, this does.

Do you want all THREE volumes to be accessible simultaneously? That is,
drive C, drive D and the synthetic drive E? If so, does each drive only
“know about” the files stored on it? In other words, when I do a
directory of E, I see the 200MB file. But when I do a directory of C
and D all I see are two drives with no (remaining) space? If there
WERE space, however, the user could choose to store files on any of the
3 drives???

If this is the goal, then it’s probably best implemented as a pseudo
file system. The backing store for this file system will be the
(existing) file systems on volumes C and D. If a trivial design like
setting the files that are stored on C and D as “hidden” isn’t
acceptable, you’ll probably need a file system filter to sit on top of
the C and D volumes to hide the existence of these files (the the
synthetic file system’s meta data).

Could you get it done with a team of 4 undergrads in 2-3 months? Well,
it depends on what they start off knowing. Unless they start off with a
good knowledge of Windows file systems, I’d say not likely. Simply
knowing how to write Windows drivers, or just understanding general file
systems principals, would not be enough. There are just too many details.

Peter
OSR