Re: [9fans] plan9 iso image

[Gorka Guardiola <paurea@gmail.com>]

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So... looking at the standard, the problem may be that
the volume size is in bytes instead of in blocks?

When I xd a plan 9 image (bytes are represented in little and
big endian):

0008000  01434430 30310100 504c414e 20392042
0008010  4f4f5420 49534f39 36363020 20202020
0008020  20202020 20202020 504c414e 2039202d
0008030  204d4159 20372032 30313220 32333a32
0008040  33202020 20202020 00000000 00000000
0008050  00305600 00563000 00000000 00000000
                    ^^^^^^         ^^^^^^^
volume size in bytes (should this be in logical blocks?)

0008060  00000000 00000000 00000000 00000000
0008070  00000000 00000000 01000001 01000001
0008080  00080800 0a000000 0000000a c60a0000
                    ^^^^^ ^^^^
Block size, 2K

0008090  00000000 00000ac7 00000000 2200c20a
00080a0  00000000 0ac20010 00000000 10007005
00080b0  07151737 00020000 01000001 01003956


The size of the iso given by ls is 5656576, 0x00565000
which is close enough to 0x563000 in bytes.

 I xd a 90M linux iso I have and got:

0008000  01434430 30310100 4c494e55 58202020
0008010  20202020 20202020 20202020 20202020
0008020  20202020 20202020 4344524f 4d202020
0008030  20202020 20202020 20202020 20202020
0008040  20202020 20202020 00000000 00000000
0008050  fdb30000 0000b3fd 00000000 00000000
                     ^^^^^^^^^^^^^^^^^

90M/2K

0008060  00000000 00000000 00000000 00000000
0008070  00000000 00000000 01000001 01000001
0008080  00080800 0a000000 0000000a 14000000
                  ^^^^^^^^^
2K block size
0008090  00000000 00000016 00000000 22001800
00080a0  00000000 00180008 00000000 08006b05
00080b0  1808100a 20020000 01000001 01002020

So the size should be in Blocks and it is in bytes, this is why it is wrong.

I don't understand why k3b reports double the size because it
is much more. Unless I am not seeing something...

G.






On Fri, Jun 28, 2013 at 8:57 PM, Gorka Guardiola <paurea@gmail.com> wrote:

> http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-119.pdf
>
> page 19:
>
>
> Volume Space Size (BP 81 to 88)
> This field shall specify as a 32-bit number the number of Logical Blocks
> in which the Volume Space of the
> volume is recorded.
> This field shall be recorded according to 7.3.3.
>
>
>
>
>


--
- curiosity sKilled the cat

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