I actually wasn't in this discussion.I was reading this thread,and I
accidentally clicked on the "compose" button,and I didn't know how to
cancel an email,so I had to send a blank.
-Jayden
On Thu, Feb 5, 2015 at 11:55 AM, Eric Auer <[email protected]> wrote:
>
> Hi Jayden, Imre,
>
> >> - defrag does FAT32 (you have to select the right defragmentation
> >> method from the menu)
>
> Which options do / do not work for FAT32? Could the menu
> system and dialogs be improved if that would help? For
> example instead of saying "I cannot do X on FAT32", it
> could say "I cannot do X, but I can do Y on FAT32" :-)
>
> >> - chkdsk does not do FAT32, you have to use DOSFSCK for FAT32.
> >> There is not enough memory in 16 bit to check the disk in a
> >> reasonable amout of time
>
> That is correct. I have discussed this with sparky before...
>
> >> sparky4 schreef op 15/01/2015 om 17:24:
> >>> I noticed they do not exist!
> >>>
> >>> i hope they get made soon!
>
> One of my main points was:
>
> > In particular the check for lost and cross linked clusters has the
> > issue that I even do not know an obvious method for doing it without
> > having at least size-of-one-FAT in RAM space at all, because temp
> > files are no option for chkdsk imho.
>
> ... and with FAT32, one FAT can be up to 1 gigabyte big.
> With FAT16, the maximum size of a FAT was 128 kilobytes:
> 2^28 clusters * 32 bit versus 2^16 clusters * 16 bit. In
> more realistic cases, the FAT can still be many MB large.
>
> SOME of the checks can be done without using much RAM. The
> question to all of you is: Would you like a tool for a low-
> RAM (or even 16 bit) PC which does only the low-RAM checks?
>
>
>
> I made this list of things that dosfstools dosfsck can do.
>
> First the low RAM things:
>
> - read the boot sector and check the data there
>
> - read the first fat to see which clusters are used
>
> - read the second fat to see if they are both the same
>
> - optionally read all data sectors to test for bad sectors
>
> - recursively check all directory entries for bad content
>
>
>
> Now the high RAM things:
>
> - for each directory entry, check which clusters it uses
> (as far as I know, the expected amount is not specified)
>
> - check if some clusters are used by no directory entries
> (lost clusters) or by several (cross linked files)
>
> - check that each directory can only be reached in one way
>
> - check if the free cluster statistics are correct
>
>
>
> Things which would really like some caching of data:
>
> - check if all long file name fragments form working name
> chains, without truncations or orphaned fragments
>
> - check if entries have too few or too many clusters as
> compared to the specified file size
>
> - check if all "." and ".." directory entries make sense
>
> - for any of the checks, try to repair any errors, either
> automatically or with help of user decisions
>
>
>
> I do not know how exactly the long file name checking
> works, but that probably can be done with a buffer which
> holds only one directory at a time. Still, even those
> can reach arbitrary size.
>
> In particular checking for lost or cross linked cluster
> chains needs at least the size of one fat of temp data,
> in dosfsck even more because it will tell you WHICH two
> files are crosslinked instead of only saying that some
> cluster has N (instead of the expected 0 or 1) users.
>
> A number of other checks will end up reading most of the
> fat and directory metadata spread throughout the disk,
> more or less once per check, so performance might still
> be acceptable with some EMS based disk cache. Note that
> both UIDE and LBACACHE only support XMS, which is only
> commonly available on computers with 32 bit capable CPU.
>
> Regards, Eric
>
>
>
>
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