Re: Toll Booth and junk (was Re(fcc): TI-H: Radio/In...)
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Re: Toll Booth and junk (was Re(fcc): TI-H: Radio/In...)
>From: "ns [despuqué]" <worldsnow@hotmail.com>
>It isn't necessary to have a file system, unless you want to remove the
>HDD from the mp3 player and mount it directly to a computer...
Depends on what you mean by file system. By file system
I mean an organizational system by which the player can
keep track of its MP3 data. I believe that this falls
under the definition of a "file system" albet a simple one.
I'd set up about the first 50k-100k of the disk as an
allocation table, containing up to 500 blocks of about
200 bytes to describe the song info and data start and
end positions on the disk. This would give you up to
about 500 songs on the player.
Fragmentation wouldn't be a big deal for most people,
as I wouldn't expect too much shuffling of songs, but
the player should try to fit songs into any gaps in the
system, to keep free space fragmentation to a minimum.
Deleting a song would be as simple as marking the first
character in its allocation block with a special character.
When new songs are to be added the MP3 player would
simply scan the allocation table for a free block, when
it found one it would check to see if it had been
previously used (start and end pointers not null), and
if so, verify that the space is long enough. If so it
would use that block, if not it would continue scanning.
With lots of adding and deleting it would eventually be
necessary to defragment the free space, but that could
be as simple as writing the entire data structure to the
computer, formatting the allocation table and writing
the data back. Might take a while with a gig of data.
Alternately someone could write a free space defragmenter
for it (pretty easy, just scan the allocation table for
gaps between the end pointer of a song and the start of
the next song, if found, copy the data backwards into
the gap and reset the start/end pointers, then go to
the next song.
DK
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