In article 200105151140.NAA09220@goedel.fjf.gnu.de, Frank Heckenbach frank@g-n-u.de writes

Martin Liddle wrote:

...

Does anybody have a code fragment to read the boot sector of a PC running Linux (Red Hat 6.2 if it matters)?

Linux by itself does not use a boot sector. It can be loaded by various boot loaders like LILO, grub or loadlin. While the latter one is a Dos executable, the former two contain their own boot sectors. You may want to look into their source code (C, of course) to find out more.

I think my terminology may be faulty. What I am after is the Master Boot Record (MBR) which I think will be present on a PC, almost irrespective of the operating system. I have downloaded the source for grub but there is a lot to plough through. I just hoped somebody had done it before.

On Tue, 15 May 2001, Frank Heckenbach wrote:

Martin Liddle wrote:

...

In article 200105151140.NAA09220@goedel.fjf.gnu.de, Frank Heckenbach frank@g-n-u.de writes

...

Martin Liddle wrote:

...

Does anybody have a code fragment to read the boot sector of a PC running Linux (Red Hat 6.2 if it matters)?

Linux by itself does not use a boot sector. It can be loaded by various boot loaders like LILO, grub or loadlin. While the latter one is a Dos executable, the former two contain their own boot sectors. You may want to look into their source code (C, of course) to find out more.

I think my terminology may be faulty. What I am after is the Master Boot Record (MBR) which I think will be present on a PC, almost irrespective of the operating system. I have downloaded the source for grub but there is a lot to plough through. I just hoped somebody had done it before.

Yep, on a Linux system, usually lilo or grub is stored in the MBR (though they can also be stored elsewhere).

Frank

I do not know whether this will be of any help, but on FreeBSD-Systems you will find a command # boot0cfg -f file ad0 which will print the content of the MBR on disk ad0 into file . Perhaps you will find something similar for Linux? Have a look at # man boot !?

Uli.

################################################### # # # www.pukruppa.de www.2000d.de # # # ###################################################

Martin Liddle wrote:

To answer my own question, I finally managed to start to think and came up with this, which seems to do what I want:

Var InBuffer: Array[0..511] of Byte; InFile:File;

Reset(InFile,'/dev/hda',512); Blockread(Infile,InBuffer,1);

OK, if you only want the raw data, sure, you can just read them from the device. I was thinking more complicated -- to get some more readable information or something ...

Frank

On Tue, 15 May 2001, Frank Heckenbach wrote:

Martin Liddle wrote:

...

To answer my own question, I finally managed to start to think and came up with this, which seems to do what I want:

Var InBuffer: Array[0..511] of Byte; InFile:File;

Reset(InFile,'/dev/hda',512); Blockread(Infile,InBuffer,1);

OK, if you only want the raw data, sure, you can just read them from the device. I was thinking more complicated -- to get some more readable information or something ...

In case someone later wants to write something there it would be safer to think in terms of a record. Otherwise messing with that last 66 bytes is an invitation to disaster.

type PartitionRec : array[ 1..16 ] of byte;

TMBR = record bootcode : array[ 1..446 ] of byte; PartitionTable : array[ 1..4 ] of PartitionRec; validsig : shortcard; { = AA55h } end;