[syslinux] [PATCH 1/5] fat: fix minfatsize for large FAT32

[Ady]

> On 02/26/16 09:54, Gene Cumm via Syslinux wrote:
> >>
> >> I'm not exactly sure how that would work (how would you mark those clusters
> >> as wasted when my understanding is that the FAT's can't provide any
> >> knowledge about them in the first place?) and unless it is automatically
> >> integrated and ran during the Syslinux installation, it sounds quite
> >> inconvenient for users.
> > 
> > Total size and last-known free space should be adjusted accordingly.
> > I don't think there's anything more but a fsck/chkdsk or similar tool
> > should also be able to fix this error.  Ending the file system before
> > the end of the partition may seem unusual but helps in this instance.
> > 
> 
> And that is, indeed, what this formatter should do if it wishes to
> continue using this specific algorithm for some reason.  This is, in
> fact, required anyway for some specific reasons.
> 
> That being said, if Windows accepts such a filesystem then Syslinux
> really should, too; perhaps with a warning.  libfat is sometimes overly
> paranoid, on purpose, in order to avoid problems.
> 
> It is also worth noting that someone ported mkdosfs to Windows; perhaps
> the best thing would be if this could be folded into the stock
> dosfstools upstream (if it hasn't been already):
> 
> 	http://www1.mager.org/mkdosfs/
> 
> 	---
> 
> TL;DR: Ridgecrop's tool has a bug that needs to be fixed.  They can
> either extend the FAT size to cover the entire volume, or they can
> adjust the filesystem size to account for the limited size of the FAT.
> Both are legitimate; which one results in the higher capacity is the
> preferred one (which will usually be making the FAT larger.)
> 
> However, if Windows accepts this, and *especially* if chkdsk doesn't
> take any action, we really ought to change Syslinux to match.
> 
 
At this time, I think there is no need to patch Syslinux's minfatsize.

I am planning on performing (at some point in the near future) some 
methodical calculations around the amount(s) of clusters that delimit 
the type of FAT, just to be "more comfortable" with what I wrote 
throughout this email thread.

IMHO, and as suggested by Gene, the "-f" parameter could be the door 
for more flexibility / less "paranoia" and the "normal" commands should 
remain as they are (unless a bug is found).

In other words, we need someone to improve/expand the "-f" option for 
the SYSLINUX/EXTLINUX installation commands in a coherent manner.

Regarding Windows ports of mkdosfs, I recall:
_ a build of dosfstools 2.11 made by Uwe Mager;
_ a partial build of an old mtools version, made by Ben Lunt;
_ a build of mtools 4.0.18 (the latest available at this time) made by 
Gert Hulselmans (aka Icecube).

BTW, even the documentation / pdf of mtools has inconsistencies 
regarding the calculations of FAT size and the examples presented 
there. Unfortunately, at this time it seems mtools' author (Alain 
Knaff) is not going to improve mtools nor its documentation.

I have not checked the recent development of dosfstools, but I do know 
that there are newer commits being pushed.

Regards,
Ady.
 
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