testing HFS+ journal replay against real Apple code

testing HFS+ journal replay against real Apple code

[Hin-Tak Leung]

Hi Vyacheslav,
I was looking for powerpc emulation for a different purpose, and
came upon this collection of ideas. Apple have released
the bare darwin OS (kernel, command-line utils, etc without the Mac OS X
GUI on top) as an installable ISO, I think darwin 8 is roughly equivalent
to Mac OS X 10.4 . But as far as the file system driver is concerned,
it should be sufficient for your needs for HFS+ inter-op.

So if you have a spare computer, you can just install it... 

http://www.opensource.apple.com/static/iso/

I am thinking of making a powerpc instance with PearPC (since I have
other use of that) - apparently it work well enough, but the x86 install
probably can work with an x86 emulator/vmware, etc.

That means you can simulate unclean shutdown, etc by killing the emulator
in the middle of something, etc. and "mount -o loop -t hpfsplus" the image"
should roll the journal, etc, right?

Hin-Tak

Re: testing HFS+ journal replay against real Apple code

[Vyacheslav Dubeyko]

Hi Hin-Tak,

On Thu, 2014-02-06 at 13:45 +0000, Hin-Tak Leung wrote:
> Hi Vyacheslav,
> I was looking for powerpc emulation for a different purpose, and
> came upon this collection of ideas. Apple have released
> the bare darwin OS (kernel, command-line utils, etc without the Mac OS X
> GUI on top) as an installable ISO, I think darwin 8 is roughly equivalent
> to Mac OS X 10.4 . But as far as the file system driver is concerned,
> it should be sufficient for your needs for HFS+ inter-op.
> 
> So if you have a spare computer, you can just install it... 
> 
> http://www.opensource.apple.com/static/iso/
> 
> I am thinking of making a powerpc instance with PearPC (since I have
> other use of that) - apparently it work well enough, but the x86 install
> probably can work with an x86 emulator/vmware, etc.
> 
> That means you can simulate unclean shutdown, etc by killing the emulator
> in the middle of something, etc. and "mount -o loop -t hpfsplus" the image"
> should roll the journal, etc, right?
> 

Thank you for the advice. I'll consider this way.

Currently, I have for testing two MacMini with different versions of Mac
OS X for testing. And I use external flash sticks and external drives
for testing. I suppose that such way gives more freedom for generation
different HFS+ volumes' configurations (block size, journal size and so
on) and states (workloads, journal content, journal state and so on)
under Mac OS X than it can be achieved for rootfs. Also, such way gives
more precise way for sudden power-off emulation, I suppose.

But, anyway, your suggestion can be useful, I think.

Thanks,
Vyacheslav Dubeyko.

Re: testing HFS+ journal replay against real Apple code

[Hin-Tak Leung]

------------------------------
On Fri, Feb 7, 2014 5:53 AM GMT Vyacheslav Dubeyko wrote:

>Hi Hin-Tak,
>
>On Thu, 2014-02-06 at 13:45 +0000, Hin-Tak Leung wrote:
>> Hi Vyacheslav,
>> I was looking for powerpc emulation for a different purpose, and
>> came upon this collection of ideas. Apple have released
>> the bare darwin OS (kernel, command-line utils, etc without the Mac OS X
>> GUI on top) as an installable ISO, I think darwin 8 is roughly equivalent
>> to Mac OS X 10.4 . But as far as the file system driver is concerned,
>> it should be sufficient for your needs for HFS+ inter-op.
>> 
>> So if you have a spare computer, you can just install it... 
>> 
>> http://www.opensource.apple.com/static/iso/
>> 
>> I am thinking of making a powerpc instance with PearPC (since I have
>> other use of that) - apparently it work well enough, but the x86 install
>> probably can work with an x86 emulator/vmware, etc.
>> 
>> That means you can simulate unclean shutdown, etc by killing the emulator
>> in the middle of something, etc. and "mount -o loop -t hpfsplus" the image"
>> should roll the journal, etc, right?
>> 
>
>Thank you for the advice. I'll consider this way.
>
>Currently, I have for testing two MacMini with different versions of Mac
>OS X for testing. And I use external flash sticks and external drives
>for testing. I suppose that such way gives more freedom for generation
>different HFS+ volumes' configurations (block size, journal size and so
>on) and states (workloads, journal content, journal state and so on)
>under Mac OS X than it can be achieved for rootfs. Also, such way gi
>more precise way for sudden power-off emulation, I suppose.
>
>But, anyway, your suggestion can be useful, I think.
>Thanks,
>Vyacheslav Dubeyko.


Hi Vyacheslav, 

Since I wrote, I have managed to install the powerpc version of darwin 8 under pearpc. It is supposed to be equivalent to mac os x 10.4 without the GUI - I think that's probably also where journalling was first introduced? Aanyway, i do see some kernel messages about journal playback as darwin boots up, so it is useable for hfs+ journal testing purposes. 

Though once one gets it set up, the "virtual machine" is quite useable and stable (and I intended to do some unrelated dev under it), I found the latest version (0. 5, 2011) of pearpc quite broken and had to go back to older ones (0.4- in 2005). Darwin 8 was reported explicitly to work in a few mailing list posts against pearpc 0.3.1 , so I persisted. Since I was after powerpc emulation, that's what I wanted, but Macintoshes are intel-based these days, and developments of pearpc seems to have really stalled; you would probably get much better performance with intel darwin on intel chip anyway, so I suggest that if you want to explore this route, using the intel version of darwin 8 (installer iso also at the URL above) is probably a better option.

HTH,
Hin-Tak