Re: [Monotone-devel] Mac OS X - resource fork empty after checkout

[Brian May]

>>>>> "Thomas" == Thomas Keller <address@hidden> writes:

    Thomas> I have to admit that I never heard of this feature, I just learned 
about
    Thomas> it by querying Wikipedia [0]. As far as I've read it is possible to 
have
    Thomas> two-fork files on os9 (data and resource fork) and even multi-fork 
files
    Thomas> on OSX.

This is something Mac OS always has had for years.

I have heard rumours that:

- Microsoft has introduced something similar in Windows (Vista?) (for
compatibility with Mac OS?).

- As such Samba needs to be able to support it.

- Apple now consider resource forks obsolete as of Max OS X for
compatibility with Unix.

I don't know which of these are true or not, but I have heard it has
resulted in heated discussions on the Linux kernel mailing list if
Linux should support it or not in order to allow Samba to support it.

What Linux does have instead (and right now) are extended attributes -
not quite the same thing, but similar. Extended attributes are
designed for small pieces of information, but resource forks can
potentially be very large.

    Thomas> Now the interesting questions are:

    Thomas> 1) Is the data fork always the file's content and can therefor be 
read
    Thomas> out just as "normal"?

A fork is just a separate stream in the file - a bit like if the file
was really a directory and the forks are files in that directory.

    Thomas> 2) Are there command line utilities available which can read 
out/write
    Thomas> multi-fork files?

I don't think it would be hard to write a utility if one doesn't
exist.

    Thomas> If the answer to both is yes, one could probably hack something 
together
    Thomas> which sets the resource fork of a file as attribute file on checkin 
and
    Thomas> on update/checkout reconstructs the file the other way around. The
    Thomas> neccessary hooks for monotone are documented here [1] under 6.1.10.

My memory has gone, and I can't be bothered to look up the details right now.

Are attributes in monotone suited for storing large amounts of data? 
If not, they might be OK for extended attributes, but not forks.
-- 
Brian May <address@hidden>