Re: Using raw read to read Hard disk sectors

"Alex Blekhman" <>
Fri, 9 May 2008 11:37:37 +0300
"SD" wrote:

I want to use raw read() to read and dump out contents of the
sectors of a hard disk partition. I searched on the net but
haven't found very useful links. I want to do this using just
plain "C" without using any Win32 APIs.

First of all, what do you mean by "plain C"? ANSI C? If it's the
latter, then `read' is not plain C. The function `read' is
deprecated and the standard conformant name is `_read'. On other
words, you can't perfom such platform specific operation as
reading the sectors of a hard disk partition in ANSI C. You will
have to use platform specific API or vendor specific CRT
extensions one way or another.

Here's the program that reads 1MB of data from second hard disk in
the system:

int main()
    LPCTSTR pszDisk = _T("\\\\.\\PhysicalDrive1");

    int d = _topen(pszDisk, _O_BINARY | _O_RDONLY);

    const SIZE_T n = 1024 * 1024;
    PBYTE buff = new BYTE[n]();

    int res = _read(d, buff, n);


    if(res != -1)
        // do something with the buffer
        // ...

    delete[] buff;

    return 0;

See more info about opening physical drives in MSDN article for
`CreateFile' function.


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