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Subject: Re: error in disk write code
From: Greg Haerr (
Date: 2002-11-08

: > : ./fat mkfile /a 3000
: > :
: > : fails with the CVS code. It seems that files over about 2MB don't work.
: Works for me. What error do you get?

"Panic: Cluster chain too short"

This happens only when the disk is formatted with
sectors per cluster = 1. (./fat ds 0, byte 14 = 01)

By default, the "mkdosfs -F 32" does this. If
"mkdosfs -F 32 -s 4" is used, it works. This is
because of the FAT cache code being restricted
to working for 0x20 (32) sectors only.

: What is wrong with the cache algorithm? I can't see any error in there.

I haven't traced it down to there yet. I quickly thought
that might be the issue, since when sectorspercluster = 1,
the FAT sectors just happens to go above 0x20.

: > How does the current read code handle large files if the clustersize
: > is 1? It appears that it wouldn't work, but I haven't been able to
: > test yet.
: Why wouldn't it? Please explain.

The read/write is identical in this case, so I was just trying to see
how file reading would work if file writing didn't for the sectorspercluster=1
case. I'll bet that the JB hard drives aren't formatted with spc=1...

: > Of course, larger mp3's play properly. Does anyone
: > know the default clustersize on the JB?
: That depends on what program you used for formatting the disk and how
: large it is.

Hmm. I thought it came preformatted but can't remember. If not,
then I used the default "format e:" on Win98 SP2.



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