Hi L. D. and all,
On Fri, 29 Dec 2000 18:47:24 -0500, L.D. Best wrote:
> Dave,
> I didn't quote the long explanation of how the FAT is, or is not,
> involved in a search for files on a HDD ...
> You refer to the OS searching the "Directory" to find a file address,
> and state that the search of the directory entry does NOT involve the
> FAT in any way.
> -----------
> My question(s) is/are:
> Isn't a directory no more than just another file? Aren't all the
> directories kept track of by the FAT? If directories are not kept track
> of by the FAT, how *are* they kept track of?
Yes, with one exception: the root directory of a FAT formated drive is
no file but a special area located between boot sector and first copy of
FAT. So the root directory of a FAT16 drive has a limited number of
directory entries. All subdirectories are indeed a special kind of file
(there is a special subdir attribute to indicate this).
> I know that the files referred to as Directories can be written anywhere
> on the HDD that there is space, so how can accessing the FAT be avoided?
It can't be avoided. Let's have an example:
Assuming You have a directory named "parents" which contains a subdir
named "children" OS will do as follows when "children" is to be accessed:
OS will search root directory for the name "parents". It will find the
"subdir" attribute so it will know that the entry referes to a subdir.
It looks in root dir for the first entry in FAT belonging to "parents"
to locate the first cluster on the disk containing first part of the
subdir. Tracking the FAT entries (a chain of numbers refering to the
clusters on the drive) it reads content of "parents". This will be
searched for the name "children" and the game sarts from the beginning.
> I also know that directory size can change, grow when more files are
> moved "to" a specific directory. That would indicate to me that even a
> Directory can become fragmented ... which would, AFAIK, then seem to
> require the FAT to tell the OS where to search for the rest of it.
Seems very correct for me.
<snip>
Regards Joerg
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