Re: Versioning Plugin

[Hans Reiser <reiser@namesys.com>]

David Masover wrote:

>Ming Zhang wrote:
>  
>
>>On Fri, 2005-11-11 at 16:56 -0800, Peter van Hardenberg wrote:
>>
>>    
>>
>>>On November 11, 2005 05:59 am, John Gilmore wrote:
>>>
>>>      
>>>
>>>>Does anybody remember GoBack? It was a versioning
>>>>system for windows 95/98 that was incredibly flexible and useful. Tracked
>>>>all changes to the whole disk. Old versions of a file? no problem. grab an
>>>>old version of a directory for referance temporarily? easy. Got a virus?
>>>>revert the whole HD, and then grab the newer copies of your documents and
>>>>saved games as needed.
>>>>        
>>>>
>>>My thoughts on this:
>>>
>>>The versioning would be an audit plugin. When the file is modified, tag the 
>>>current version, copy it into a sub-directory (oh, I don't know, say 
>>>file/.revisions/<number/date>), and disable write access to it. You might not 
>>>even need extended filesystem attributes for this, but they would be handy 
>>>for tagging particular versions.
>>>      
>>>
>>if a file is opened, modified 2 times, then closed. u will only generate
>>1 version right? so "When the file is modified" is inaccurate.
>>    
>>
one could do it for every file close, and that could be a state option
for the versioning plugin, but most users will want to do it everytime
they touch filename/..../checkin

>
>How about "When the transaction was completed?"  Why does it matter?
>
>  
>
>>>Copy-on-write would make this action extremely cheap, only adding a couple of 
>>>extra writes to make it work.
>>>      
>>>
>>add 1 line at the beginning of a 100MB text file will make this uncheap.
>>    
>>
>
>Who has to work with 100 meg text files?  And why has this person not
>broken them down into 100 kilobyte text files?  Storage efficiency isn't
>really an issue there...
>  
>
you need cross-version compression for this case. 

>Anyway, I think the main win is from copy-on-write for the whole file.
>
>
>
>  
>