Re: running ditto from firefox on snow leopard
Re: running ditto from firefox on snow leopard
- Subject: Re: running ditto from firefox on snow leopard
- From: Shantonu Sen <email@hidden>
- Date: Wed, 27 Jan 2010 08:30:08 -0800
It sounds like you have all the tools to resolve this, I'm not sure what input you are requesting from the low-level Darwin OS community.
If Firefox already has a mechanism for self-patching using binary deltas, it must have already solved the authentication issue. Self-patching should be enhanced to use ditto --hfsCompression on each file after the patch is applied on 10.6. Future versions of the OS may or may not support similar technology (that's why there's no API for filesystem-level compression).
On first launch, Firefox could detect it's on 10.6 and synthesize a phantom patchset that applies to every file with 0 diffs, which should have the side effect of compressing files afterward.
However, if your launch time is really affected by this in a substantial way, there are probably things you can do to improve the footprint without resorting to filesystem compression, like using order files, or making sure you put read-only data in the text segment so that it only gets paged in on demand.
Also, note that filesystem-level compression is HFS+-specific, and will not work on other filesystems, and indeed since it is a system implementation detail, may not work in the way you expect it to in the future.
Shantonu Sen
email@hidden
Sent from my Mac Pro
On Jan 27, 2010, at 1:03 AM, Jean-Daniel Dupas wrote:
>
> Le 27 janv. 2010 à 09:34, Joel Reymont a écrit :
>
>>
>> On Jan 27, 2010, at 8:29 AM, Jean-Daniel Dupas wrote:
>>
>>> wrong, partial update do not prevents codesign. Especially as the partial update can contains the updated code signature.
>>
>> Can partial updates preserve compression on Snow Leopard?
>>
>> How does Apple do this?
>>
>> In other words, can we deliver a compressed Firefox for Snow Leopard -and- deliver compressed updates as well? I gather that the objection is to compress Firefox post-installation.
>>
>
> Apple uses pkg to distribute their software and their updates. They don't have to support system older than the target one (as they distribute one package by major version if when needed), and the pkg format supports HFS compression (a class-dump of the private PackageKit reveal a useHFSPlusCompression property in PKPackageInfo), but as I avoid pkg as much as I can, I don't know if this is a public features and how to use it.
>
>
> -- Jean-Daniel
>
>
>
>
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