[NTLUG:Discuss] Re: mounting drives from other os -- FATxx v. VFAT

[Bryan J. Smith]

MontyS at videopost.com wrote:
> FAT32 would probably work, but trying to get the clients to use FAT32 on a
> consistant basis would be difficult.  Heck, I can't remember if FAT32
> requires the 8.3 file naming syntax.  If this is the case, FAT32 wouldn't
> work because we would need more than 8 characters for filenames.  We could
> easily have over 10,000 frames. Just setting up the numbering sequence would
> take up 6 characters.  Our clients would never go for that :/

On Wed, 2004-09-22 at 16:27, Chris Cox wrote:
> Sounds like FAT32 is your best bet.  It handles long filenames pretty well.
> I know it's a pain.. but you know most external drives are pre-formatted
> FAT32 and NOT NTFS... even today.  That's just going to have to be something
> the client will have to remember if creating a new filesystem on the
> external drive.

Remember, FAT12/16/32 as a "filesystem" is _separate_ from VFAT
"indexing" atop of the filesystem.

FAT12/16/32 is fully supported even in 16-bit Real86 mode of MS-DOS 7.x
(Windows 95, 98, ME).  Microsoft does not include a driver for VFAT for
MS-DOS 7.x in Real86.  So only 8.3 is usable with the Int20-3Fh DOS
services.

VFAT is enabled in MS-DOS 7.x when the DPMI (DOS Protected Mode
Interface) subsystem is loaded, and the Windows 4.x VXD/DLLs subsystems
come up.  Then added Int20-3Fh DOS functions/extensions load those
indexes and support longer filenames.

Caldera/Lineo/DeviceLogistics DR-DOS 7/8.x has a DPMI driver that
implements these extended Int20-3F DOS functions for VFAT.  This support
is loaded without having to have Windows 4.x VXD/DLLs.

-- Bryan

P.S.  This approach is, of course, completely _different_ than how it is
implemented in NT.  This is because the "Chicago" group (MS-DOS 7.0)
_completely_ignored_ the Win32 API, which make the creation of "Cairo"
(consumer NT, _never_shipped_) impossible.  It was not until NT 5.0
(2000) that Microsoft implemented the "Chicago"/MS-DOS 7.0 Int20-3Fh
extended services for VFAT -- which could be an application issue in
versions prior.

P.P.S.  For anyone who watched "Cairo" unravel, "Longhorn" is a great
repeat of history 10 years later.  It looks like "Avalon" (.NET desktop
atop of "Chicago/XP"-polluted Win32) is not getting anywhere and it
_will_ be axed next.



-- 
Bryan J. Smith                                  b.j.smith at ieee.org 
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