JM> If Microsoft owns HPFS, why did they make a new NTFS?  
 JM> Or is this a better version of HPFS?

MB>NTFS has a number of enhancements to and is a natural evolution of HPFS. 
MB> While HPFS was designed to be quickly handled on a 16-bit 
MB>processor, NTFS is designed for a 32-bit processor.  
MB>Several important features have also been added to NTFS, 
MB>especially support for dynamic rather than static memory 

   Linux supports dynamic caching of FAT partitions...

MB>cache. The data on disk is very similar between HPFS and 
MB>NTFS, although the implementation is quite different.

   The only difference between NTFS and HPFS on disk is logging in NTFS. 
Differences in implementation don't matter too much as they can be easily
changed (the implementation apparently changes in almost every version of
OS/2 anyway, not that you would notice).

 MB> comparison even with such modern developments as the Linux
 MB> Second Extended file system, which someone someday will
 MB> probably port to OS/2.

   The second extended filing system is not really a modern development. 
The design of it is a whole generation behind the design of HPFS.  HPFS
doesn't have any limits to the number of files on disk etc.  With E2FS you
make a filing system and specify the maximum number of files (the number of
Inodes).  If you decide you need more later on then you re-format!  Under
HPFS if you need more files then you just store them on.  Under HPFS the
meta-data can (and does) expand and reduce in size dynamically depending on
usage.

    I hope that IBM put the AIX logging file system into Workplace...

 JM> This is interesting.  How hard would this be to do?  I 
 JM> was toying with the idea of trying to write and IFS for 
 JM> OS/2 to read my Linux partition.  That sounds rather 
 JM> tough, though.

MB>I don't think it would be very hard.  OS2DASD.DMD provides 
MB>logical sector I/O which is analogous to Linux services 
MB>already, and most of the work would be in providing a 
MB>necessary encapsulation of the Linux driver functions into 
MB>the OS/2 IFS format.  An OS/2 IFS is actually just a DLL 
MB>that exports certain reserved symbols and runs at Ring 0.

   It wouldn't be that hard conceptually.  However there are 2 ways of
doing this.  The first way is to get the Linux code for a particular filing
system and hack it until it fits into an OS/2 IFS.  Then when the original
Linux code gets bug-fixes or new features you will have heaps of problems
keeping up.  Also when a new more advanced filing system comes out you
would have to start again from scratch.
    The better way would be to write some libraries that map the OS/2 IFS
interfaces to the Linux VFS interfaces, then you would hardly have to
change the actual Linux filing system code, so you would have no problems
applying patches and could implement new filing systems without too many
problems.


     cya
___
 X MR/2 2.0 NR X New from McAfee: WinScan. Removes all Windows programs.

--- Maximus/2 2.02
@Via 3:632/103.0 {at}19950130.084310.UTC NetMgr 0.99 [unreg]