C / C++ / MFC

31-May-07 20:40

I used CreateFile() API to open a hard drive in raw format. But it failed. What are the correct parameters for the API ? Please help me.

Cedric Moonen31-May-07 20:54

Cedric Moonen

31-May-07 20:54

Srinivas Kaparthi wrote:
to open a hard drive in raw format

What do you mean opening a hard-drive ? You mean opening a file, right ? And what is raw format ? Binary mode ?

Srinivas Kaparthi wrote:
But it failed

What failed ? What happened exactly ? It crashed, it didn't compile, ... ? What messages did you get ? What did you expect and what happened ?
And also, post the code you use to open the file.

Cédric Moonen
Software developer

Charting control [v1.2]

Srinivas Kaparthi3-Jun-07 22:32

3-Jun-07 22:32

Hello,
Thank you for your reply.
Opening a hard drive does not mean opening a file.
raw format means the complete disk/partition is treated as a single file. By opening in raw format, we can read sectors directly. This method is called raw IO. This is also called as Direct Disk/Drive Access. Please refer to the Kakan's reply for my problem. It is working fine.

Cedric Moonen3-Jun-07 23:42

Cedric Moonen

3-Jun-07 23:42

Nice, I learned something today Big Grin | :-D

I didn't know that we could open the disk in raw format. Thanks for the tip Wink | ;)

Cédric Moonen
Software developer

Charting control [v1.2]

kakan4-Jun-07 19:24

4-Jun-07 19:24

Yes, it's possible to open either a partition or a physical disk (including the partition table). And modify (with the correct access rights of course).
So we got all possibilities to mess things up! Smile | :)

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

kakan31-May-07 22:39

31-May-07 22:39

I use this code.
Beware, it's C and not unicode compliant. Adjust it if you want to.
m_UseDrive is the drive letter to open, i.e: 'C'

sprintf(Drive,"\\\\.\\%c:", m_UseDrive);
hDrive = CreateFile(Drive, GENERIC_READ | GENERIC_WRITE,
    FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);

But when you read from it, you MUST use a multiple of the sector size. Else, the read will fail. The same goes for seeking.
You can find out the sector size by a DeviceIoControl-call, and get the disk geometry. (Search for documentation of the DISK_GEOMETRY struct).

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

Srinivas Kaparthi1-Jun-07 21:44

1-Jun-07 21:44

I used a dialog based application. For OK Button click handler I wrote the following code as suggested by you. But I could not succeed. Is it that Administrator login is essential? What is meant by UNICODE complianr?

<br />
char Drive[20] , m_UseDrive = 'C' ;<br />
HANDLE hDrive ;<br />
<br />
	<br />
sprintf(Drive,"\\\\.\\%c:", m_UseDrive);<br />
hDrive = CreateFile(Drive, GENERIC_READ | GENERIC_WRITE,	FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);<br />
if(hDrive == INVALID_HANDLE_VALUE)<br />
      AfxMessageBox("Succeeded") ;<br />
else<br />
      AfxMessageBox("Drive could not be opened") ;

kakan3-Jun-07 19:41

3-Jun-07 19:41

Hello.

I always use the "disclaimer" about my source code not beeing Unicode compliant, and has C syntax.
In the past, I've been flamed a number of times, by people who were complaining about my source code. Nowadays, I always use that statement.

About your code example: You have switched your test/texts, so if you get "Drive could not be opened", all is fine, and the drive is open for use! Smile | :)

Just remember, all operations must be done on an even multiplier of the sector size (since a complete sector is the smallest amount that the drive can handle. It's ususally 512 bytes, but can differ).

Alcohol. The cause of, and the solution to, all of life's problems - Homer Simpson

Srinivas Kaparthi3-Jun-07 22:24

3-Jun-07 22:24

Thanks a lot! Smile | :)

Srinivas Kaparthi4-Jun-07 6:40

4-Jun-07 6:40

Under Windows 98, it fails. Is there any solution?

kakan4-Jun-07 19:01