bios dump - Linux

This is a discussion on bios dump - Linux ; Hello, I managed to use the dd program to obtain a dump of my computer's bios assuming that the start address is 0xffff0 and is 64k in size. I ran file on the file and it reported data file. Now ...

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Thread: bios dump

  1. bios dump

    Hello,

    I managed to use the dd program to obtain a dump of my computer's bios
    assuming that the start address is 0xffff0 and is 64k in size. I ran file on
    the file and it reported data file. Now I have tried to look at the bios in
    a hex editor I have for windows but nothing shows up. Are their any file
    attributes that I might need to change in order to be able to read this in a
    hex editor?

    Bill



  2. Re: bios dump

    Bill Cunningham wrote:
    > Hello,
    >
    > I managed to use the dd program to obtain a dump of my computer's bios
    > assuming that the start address is 0xffff0 and is 64k in size.


    I presume that this is on an IBM Compatible Computer using a Pentium compatible
    processor.

    How did you do the dump?

    Remember you need to obtain the physical (real mode) address, and your first
    instruction will be a jump to another address.

    Regards,

    Mark.

    --
    Mark Hobley
    393 Quinton Road West
    QUINTON
    Birmingham
    B32 1QE

    Telephone: (0121) 247 1596
    International: 0044 121 247 1596

    Email: markhobley at hotpop dot donottypethisbit com

    http://markhobley.yi.org/


  3. Re: bios dump


    "Mark Hobley" wrote in message
    news:smvi74-5dh.ln1@neptune.markhobley.yi.org...
    > Bill Cunningham wrote:
    >> Hello,
    >>
    >> I managed to use the dd program to obtain a dump of my computer's bios
    >> assuming that the start address is 0xffff0 and is 64k in size.

    >
    > I presume that this is on an IBM Compatible Computer using a Pentium
    > compatible
    > processor.


    AMD 64. Is there a difference in bios standards?

    > How did you do the dump?
    >
    > Remember you need to obtain the physical (real mode) address, and your
    > first
    > instruction will be a jump to another address.


    Indeed this interrupt would be triggered before the kernel loaded into
    memory so I am assuming this isn't a virtual address.

    Bill



  4. Re: bios dump

    Bill Cunningham wrote:
    >
    > Indeed this interrupt would be triggered before the kernel loaded into
    > memory so I am assuming this isn't a virtual address.
    >


    It depends on how you did the dump. If you did the dump in real mode, using a
    DOS based system, then it would be a physical address. If you did the dump in
    protected mode, which I presumed you had, because this is a Linux newsgroup,
    so I guessed you had a Linux kernel running, and the processor is in protected
    mode, you may have dumped data from a virtual address which does not correspond
    to the bios code. I will confess at this point though that I am only familiar
    with IBM compatible architecture (32 bit), so I don't know how a 64 bit machine is
    layed out, but I guess it still supports real mode, and is compatible with
    existing 16 bit and 32 bit software.

    Regards,

    Mark.

    --
    Mark Hobley
    393 Quinton Road West
    QUINTON
    Birmingham
    B32 1QE

    Telephone: (0121) 247 1596
    International: 0044 121 247 1596

    Email: markhobley at hotpop dot donottypethisbit com

    http://markhobley.yi.org/


  5. Re: bios dump

    Mark Hobley wrote:

    Hey Bill ...

    I found a whole load of stuff on memory addressing. I don't know how useful it
    is to you. (There are more links on the left of the page also).

    http://www-128.ibm.com/developerwork...rary/l-memmod/

    Regards,

    Mark.

    --
    Mark Hobley
    393 Quinton Road West
    QUINTON
    Birmingham
    B32 1QE

    Telephone: (0121) 247 1596
    International: 0044 121 247 1596

    Email: markhobley at hotpop dot donottypethisbit com

    http://markhobley.yi.org/


  6. Re: bios dump

    Bill Cunningham wrote:

    > Hello,
    >
    > I managed to use the dd program to obtain a dump of my computer's bios
    > assuming that the start address is 0xffff0 and is 64k in size. I ran file on
    > the file and it reported data file. Now I have tried to look at the bios in
    > a hex editor I have for windows but nothing shows up. Are their any file
    > attributes that I might need to change in order to be able to read this in a
    > hex editor?
    >
    > Bill
    >
    >

    BIOS's stopped being 64K long time ago ( 486 i think ) so it is unlikely you have the entire thing. I think it was 256K in 350 500MHz days.

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