Libguestfs - Dec 2014 - Re: does guestfs_list_partitions() work with Windows 95 images?

>
> Looks like a disk sector to me too.  However the partition table
> is further on.  See:
>
> https://en.wikipedia.org/wiki/Master_boot_record#Sector_layout

So that reference says the "classical generic MBR" partition entry # 1
is
offset 0x1BE.
Which in this image is right in the error strings (?) section.

00000170  13 59 5A 58 72 09 40 75 01 42 03 5E 0B E2 CC C3  .YZXr.@u.B.^.âÌÃ
00000180  03 18 01 27 0D 0A 49 6E 76 61 6C 69 64 20 73 79  ...'..Invalid sy
00000190  73 74 65 6D 20 64 69 73 6B FF 0D 0A 44 69 73 6B  stem diskÿ..Disk
000001A0  20 49 2F 4F 20 65 72 72 6F 72 FF 0D 0A 52 65 70   I/O errorÿ..Rep
000001B0  6C 61 63 65 20 74 68 65 20 64 69 73 6B 2C 20 61  lace the disk, a
000001C0  6E 64 20 74 68 65 6E 20 70 72 65 73 73 20 61 6E  nd then press an
000001D0  79 20 6B 65 79 0D 0A 00 49 4F 20 20 20 20 20 20  y key...IO
000001E0  53 59 53 4D 53 44 4F 53 20 20 20 53 59 53 80 01  SYSMSDOS   SYS€.
000001F0  00 57 49 4E 42 4F 4F 54 20 53 59 53 00 00 55 AA  .WINBOOT SYS..Uª
00000200  F8 FF FF FF FF FF 04 00 FF FF 06 00 FF FF 08 00  øÿÿÿÿÿ..ÿÿ..ÿÿ..

So if that is where guestfish is looking for the partition table...

I searched for other references. Found this one and it agreed with this
0x1BE value.
http://www.win.tue.nl/~aeb/partitions/partition_types-2.html

Any other locations that you know of?

On Tue, Dec 16, 2014 at 11:33:00AM -0500, Skippy VonDrake
wrote:
> >
> > Looks like a disk sector to me too.  However the partition table
> > is further on.  See:
> >
> > https://en.wikipedia.org/wiki/Master_boot_record#Sector_layout
> 
> 
> So that reference says the "classical generic MBR" partition
entry # 1 is
> offset 0x1BE.
> Which in this image is right in the error strings (?) section.
> 
> 00000170  13 59 5A 58 72 09 40 75 01 42 03 5E 0B E2 CC C3  .YZXr.@u.B.^.âÌÃ
> 00000180  03 18 01 27 0D 0A 49 6E 76 61 6C 69 64 20 73 79 
...'..Invalid sy
> 00000190  73 74 65 6D 20 64 69 73 6B FF 0D 0A 44 69 73 6B  stem diskÿ..Disk
> 000001A0  20 49 2F 4F 20 65 72 72 6F 72 FF 0D 0A 52 65 70   I/O errorÿ..Rep
> 000001B0  6C 61 63 65 20 74 68 65 20 64 69 73 6B 2C 20 61  lace the disk, a
> 000001C0  6E 64 20 74 68 65 6E 20 70 72 65 73 73 20 61 6E  nd then press an
> 000001D0  79 20 6B 65 79 0D 0A 00 49 4F 20 20 20 20 20 20  y key...IO
> 000001E0  53 59 53 4D 53 44 4F 53 20 20 20 53 59 53 80 01  SYSMSDOS   SYS€.
> 000001F0  00 57 49 4E 42 4F 4F 54 20 53 59 53 00 00 55 AA  .WINBOOT SYS..Uª
> 00000200  F8 FF FF FF FF FF 04 00 FF FF 06 00 FF FF 08 00  øÿÿÿÿÿ..ÿÿ..ÿÿ..
This doesn't look like any partition table I've seen before.

It's possible that the disk is not partitioned, ie. that what you've
got here is a straight filesystem.  You could see if libguestfs can
mount it:

  guestfish --ro -a disk.img -m /dev/sda
  ><fs> ll /

[...]
> Any other locations that you know of?
There exist other kinds of partition table, but none that Win95 would
have known how to use.

Rich.

-- 
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On Wed, Dec 17, 2014 at 02:16:09PM +0000, Richard W.M. Jones
wrote:
> On Tue, Dec 16, 2014 at 11:33:00AM -0500, Skippy VonDrake wrote:
> > >
> > > Looks like a disk sector to me too.  However the partition table
> > > is further on.  See:
> > >
> > > https://en.wikipedia.org/wiki/Master_boot_record#Sector_layout
> > 
> > 
> > So that reference says the "classical generic MBR" partition
entry # 1 is
> > offset 0x1BE.
> > Which in this image is right in the error strings (?) section.
> > 
> > 00000170  13 59 5A 58 72 09 40 75 01 42 03 5E 0B E2 CC C3 
.YZXr.@u.B.^.âÌÃ
> > 00000180  03 18 01 27 0D 0A 49 6E 76 61 6C 69 64 20 73 79 
...'..Invalid sy
> > 00000190  73 74 65 6D 20 64 69 73 6B FF 0D 0A 44 69 73 6B  stem
diskÿ..Disk
> > 000001A0  20 49 2F 4F 20 65 72 72 6F 72 FF 0D 0A 52 65 70   I/O
errorÿ..Rep
> > 000001B0  6C 61 63 65 20 74 68 65 20 64 69 73 6B 2C 20 61  lace the
disk, a
> > 000001C0  6E 64 20 74 68 65 6E 20 70 72 65 73 73 20 61 6E  nd then
press an
> > 000001D0  79 20 6B 65 79 0D 0A 00 49 4F 20 20 20 20 20 20  y key...IO
> > 000001E0  53 59 53 4D 53 44 4F 53 20 20 20 53 59 53 80 01  SYSMSDOS  
SYS€.
> > 000001F0  00 57 49 4E 42 4F 4F 54 20 53 59 53 00 00 55 AA  .WINBOOT
SYS..Uª
> > 00000200  F8 FF FF FF FF FF 04 00 FF FF 06 00 FF FF 08 00 
øÿÿÿÿÿ..ÿÿ..ÿÿ..
> 
> This doesn't look like any partition table I've seen before.
> 
> It's possible that the disk is not partitioned, ie. that what
you've
> got here is a straight filesystem.  You could see if libguestfs can
> mount it:
> 
>   guestfish --ro -a disk.img -m /dev/sda
>   ><fs> ll /
The 'blkid' command might tell you what it actually is too.

Regards,
Daniel
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