Re: [Qemu-devel] [PATCH v4 4/6] introduce new vma archive format

[Eric Blake]

On 02/21/2013 08:32 AM, Dietmar Maurer wrote:
>>>> Hint - look at how the qcow2 file format is specified.  You need a
>>>> lot more details - enough that someone could independently implement
>>>> a program to read and create vma images that would be compatible
>>>> with what your implementation produces.
>>>
>>> The format is really simple, you have the definitions in the header
>>> file, and a reference implementation. I am quite sure any experienced
>>> developer can write an implementation in a few hours.
>>>
>>> We do not talk about an extremely complex format like 'qcow2' here.
>>
>> This is not an excuse for lacking details in the spec. Quite the opposite. If
>> someone has to look at your code in order to implement the format, you have
>> failed as a spec writer.
> 
> I do not agree here. Clean source code is as good as a spec.

Not in qemu.  There's a reason that we ask for clean specs, independent
of source code.  That is the only way that we can later change the
source code to do something more efficient or to define an extension,
and still have clean documentation of what the extensions are, vs. how
an older version will behave.  The initial implementation source code
might be easy to read, but that condition is not guaranteed to last.

If reading the source code to determine the header format is as easy as
you say, then you should have no problem writing the spec as detailed as
we have asked.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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