[vbox-dev] fixed - VHD not readable by Hyper-V

[Klaus Espenlaub]

Huihong Luo wrote:
> found another bug, I've attached the patch
>  
> two bugs:
> (1) parent locators set to zero for base images
> (2) block allocation table to be block-size aligned (2M)
>  
> after these two fixes, vbox vhds works well on Hyper-V, I tested quite 
> some large vhd files from p2v, all works fine now.
>  
> These two fixes should be very safe to check in, (not sure if it may 
> break snapshots, though)

Thanks a lot for those fixes (and the previous ones as well), I'll try 
to find time myself to apply them in the near future - or find someone 
else who will handle it.

What I wanted to ask earlier already - did you read 
http://www.virtualbox.org/wiki/Contributor_information ? Which of the 
two contribution options (SCA or MIT licensed patches) do you pick?

Again, we're very grateful for the excellent contributions.

Klaus

>  
> - hl
> 
> --- On *Tue, 10/13/09, Huihong Luo /<huisinro at yahoo.com>/* wrote:
> 
> 
>     From: Huihong Luo <huisinro at yahoo.com>
>     Subject: Re: [vbox-dev] Fwd: VHD not readable by Hyper-V
>     To: "vbox-dev at virtualbox.org" <vbox-dev at virtualbox.org>
>     Date: Tuesday, October 13, 2009, 1:40 PM
> 
>     I found the vhd bug on vbox implementation. vbox mistakenly sets
>     parent locators ("wi2r", etc.) for base vhd image. If setting these
>     fields to zeros for base image, Hyper-V is happy. Should be very
>     easy to fix, if you need the code diff, let me know
> 
>     VBox The MS spec states:
> 
>     Parent Locator Entries
> 
>     These entries store an absolute byte offset in the file where the
>     parent locator for a differencing hard disk is stored. This field is
>     used only for differencing disks and should be set to zero for
>     dynamic disks.
> 
> 
>     --- On *Tue, 10/13/09, Huihong Luo /<huisinro at yahoo.com>/* wrote:
> 
> 
>         From: Huihong Luo <huisinro at yahoo.com>
>         Subject: [vbox-dev] Fwd: VHD not readable by Hyper-V
>         To: "vbox-dev at virtualbox.org" <vbox-dev at virtualbox.org>
>         Date: Tuesday, October 13, 2009, 6:49 AM
> 
> 
> 
>         Sent from my iPhone
> 
>         Begin forwarded message:
> 
>>         *From:* Huihong Luo <huisinro at yahoo.com>
>>         *Date:* October 13, 2009 6:35:42 AM PDT
>>         *To:* Shu Wu <superwushu at gmail.com>
>>         *Subject:* *Re: [vbox-dev] VHD not readable by Hyper-V*
>>
>>         No problem with vpc, vbox also understands vhds from hyper-v
>>
>>         It is just that hyper-v doesn't understand vbox's vhd 
>>
>>         Sent from my iPhone
>>
>>         On Oct 13, 2009, at 2:27 AM, Shu Wu <superwushu at gmail.com> wrote:
>>
>>>         Can your VHD disk be read by Virtual PC or Virtual Server? It
>>>         seems that Hyper-V and Virtual-PC share the same vhd format.
>>>         One year ago I wrote my own program to generate a vhd file
>>>         and make it to be accepted by Virtual PC, just following the
>>>         official vhd specification. But I haven't tested it on Hyper-V.
>>>
>>>         Cheers,
>>>
>>>         Wu Shu
>>>
>>>         2009/10/13 Klaus Espenlaub <Klaus.Espenlaub at sun.com>
>>>
>>>             Huihong Luo wrote:
>>>
>>>                 None of vbox created vhd disk files are readable by
>>>                 2008 Hyper-V.
>>>                  This is the error: "The file or directory is
>>>                 corrupted and unreadable"
>>>                  I am debugging through the code, trying to change
>>>                 Footer info, such as version, creator OS, checksun,
>>>                 etc., to see it can correct the error.
>>>                  If you know what might be wrong, pls post
>>>
>>>
>>>             We only know what Microsoft documents in their VHD format
>>>             spec, which we believe to have correctly implemented.
>>>             However as usual those specs are incomplete and not
>>>             really precise, so there's plenty of room for different
>>>             interpretations.
>>>
>>>             Klaus
>>>
>>>
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>>>
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