Re: How to start on new db-based FS?

[Hans Reiser <reiser@namesys.com>]

Daniel Mose wrote:

>Hans Reiser wrote:
>  
>
>>Daniel Mose wrote:
>>    
>>
>>>I'm doing a scan on the web for disk storage layout documentation on
>>>different file systems. I have I think, downloaded just about all 
>>>there is to download on www.namesys.com, but I fail to find anything
>>>that does describe the reiserfs storage layout in any detail.
>>>Is there such documentation available? 
>>>      
>>>
>
>I do believe that I've been somewhat unclear. What I would hope 
>to find is :
>Documentation of On-disk Per-partition storage layout 
>of file lookup and maintainance structures for reiserfs. 
>
>  
>
>>>I would be very happy for directions to it in this case.
>>>
>>>Reason? I want to know if the root file system that I my self is 
>>>      
>>>
>                                 ^^^^^^^^^^^^^^^^
>Correction, Should be: File system for root mountable partitions. 
>
>  
>
>>>about to develop perhaps is already implemented to some extent in
>>>any existing root FS:s ? 
>>>      
>>>
>                ^^^^^^^^^ 
>same correction here.
>  
>
>>What is a root filesystem? (I am accustomed to the term as describing 
>>what the OS uses for storing the semantic layer's root directory).
>>    
>>
>
>I do not have a CS - convention, or Unix background, so I am a bit
>unfamiliar with terms like "semantic layer's root directory" 
>I am a "learn by doing" type of guy, and up to now it has worked out
>ok.
>
>There seems to be a lot of discrepancies when it comes to 
>defining what a "file system" really is. I often find that the 
>term is used with widely different meanings, depending on who 
>you are actually talking to, and also in what context it is used.  
>
>I believe that the developers at www.oss.sgi, as well as the JFS 
>developers hosted at IBM, use the term: "root file system" to make 
>clear that 
>
>A.	It is a Unix type of file system, that can be used as "/"
>	at boot, i e a system "magically" mountable root partition.
>	
>B.	The file system occupies a Local mountable disk partition, 
>	and is acessible via the  Unix mount command.
>
>C.	The file system is used for file access, and maintainance of 
>	On-disk	file-lookup hierarchies, such as one or more 
>	Superblocks, File allocation scheemes ( f ex allocation group 
>	descriptors,block and inode bitmap tables, as well as inodes )
>	and Directory files ( ext2fs or FFS )
>
>I hope that this makes a bit more sense to you.
>Thank you for taking time with me, all the same
>
>I'm happy for any further direction.
>
>kind regards 
>Daniel Mose
>
>
>  
>
We are gradually adding this to our web page, and what is not present 
there can be found by reading the source code which is quite readable 
for reiser4. Look in the node plugin, disk format plugin, and item 
plugin files/directories. These have some very long winded comments 
which are not yet on our web page.;-) green@namesys.com will send you a 
tarball of the source code if you ask for it.

-- 
Hans