Re: [PATCH] pickles: Add mbr.pk for MBR partition table

[Mohammad-Reza Nabipoor]

On Tue, Jan 26, 2021 at 07:23:34AM +0100, Jose E. Marchesi wrote:
> 
> > This gives constraint violation!
> > I even tried the following alternatives:
> >   - `uint16 magic : magic == 0xaa55UH;`
> >   - `byte[2] magic = [0x55UB, 0xaaUB];` and
> >   - `byte[2] magic : magic == [0x55UB, 0xaaUB];`
> 
> Using uint16 won't work in big-endian.
> 
> byte[2] magic = [0x55UB, 0xaaUB] should work well...
> 


MBR format requires little-endian.
It uses 16-bit and 32-bit little-endian numbers.


> > +type MBR_CHS =
> > +  struct
> > +  {
> > +    byte[3] chs;
> > +
> > +    method get_head = uint<8>:
> > +      {
> > +        return chs[0];
> > +      }
> > +    method get_sector = uint<6>:
> > +      {
> > +        return chs[1] & 0x3f;
> > +      }
> > +    method get_cylinder = uint<10>:
> > +      {
> > +        return (chs[1] & 0xc0) <<. 2 | chs[2];
> > +      }
> > +    method _print = void:
> > +      {
> > +        printf ("#<head=%u8d, sector=%u6d, cylinder=%u10d>",
> > +                get_head, get_sector, get_cylinder);
> > +      }
> > +  };
> 
> Where is the CHS address format described?  Coulnd't find it in the
> MBR_(x86) article you link.

The second table in https://wiki.osdev.org/Partition_Table.
But it's not very clear.

A better document is https://formats.kaitai.io/mbr_partition_table/index.html.

Or there's a table here:
  https://en.wikipedia.org/wiki/Master_boot_record#Partition_table_entries