[R] .RData signature

[Duncan Murdoch]

stephenb wrote:
> any ideas? has anybody tried to recover RData files before?
>   

I have seen messages about that problem here before (see 
RSiteSearch(".RData corrupted") for a sampling), but I don't think I've 
seen any really satisfactory solutions.  It would be nice to have an 
error tolerant .RData dumper:  it would load and display objects until 
it hit an error, then report on the error, and perhaps partial 
information on the object it was loading.  With something like that 
you'd know if you had successfully recovered the .RData file, and if 
not, would have some hints about what was missing.

The source for the regular loader is in 
https://svn.r-project.org/R/trunk/src/main/serialize.c, and this could 
be a start for the dumper.

Duncan Murdoch
>
>
>
> Duncan Murdoch-2 wrote:
>   
>> On 7/13/2009 3:38 PM, stenka1 at go.com wrote:
>>     
>>>    Is there a way to identify the beginning and end of an .RData file?
>>>    I am trying to restore lost files on opensolaris where the table of
>>> contents
>>>    is overwritten and will be reading the raw disk byte by byte.
>>>    I looked at several files in hex and the end seems different, while
>>> most of
>>>    them, but not all begin with RDX2.X
>>>       
>> No, there is nothing special written at the end of a file.  Many .RData 
>> files are compressed (by internal gzip), so the RDX2 header is hidden, 
>> and you'll see bytes 1F 8B instead.  (I don't think we write the trailer 
>> bytes on the gzip stream, but I'm not sure about that.)
>>
>> Duncan Murdoch
>>
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>>     
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