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...)
No no no, use a bit map...that way you don't have to keep checking sector
after sector, or even fat entry after fat entry to find a free one...one
sector can hold info for 4096 sectors (1 bit per sector).
-- Jon Olson
-----Original Message-----
From: David Knaack <dknaack@hotmail.com>
To: ti-hardware@lists.ticalc.org <ti-hardware@lists.ticalc.org>
Date: Thursday, November 05, 1998 2:00 PM
Subject: Re: Toll Booth and junk (was Re(fcc): TI-H: Radio/In...)
>
>>To: ti-hardware@lists.ticalc.org
>>>Allocation table scanning as I outlined should be
>>>easy to perform, and would keep down the requirement
>>>for free space defragmentation. It also allows for
>>>song deletion without taking a big hit in storage
>>>space.
>>
>>Makes it SSSLLLOOOWWW though since the AVR doesn't have swap space for
>the
>>current sector. :)
>
>I don't know what you mean. I was refering to the AVR just
>scanning through the data in the allocation table checking
>to find a free slot big enough to store a song in.
>This would consist of a seek, read one byte, check the byte,
>if it is a 'free slot' byte, seek again, read 8 bytes (two
>4 byte values), subtract them, then check that length (the
>amount of free space at that location) against the length
>of the song to be stored. If the slot is big enough, seek
>back to the beginning of the slot, write the header, then
>seek to the data area and start writing the data. No big
>deal.
>
>>>As I mentioned, defragmentation could be as simple
>>>(and time consuming) as a backup and restore, or
>>>it could be done periodicly, when fragmented free
>>>space reaches a certain percentage (which the player
>>>could calculate at the users request, along with
>>>largest contigious block and percentage of total
>>>space used).
>>
>>Not possible from the player. It would cost too much if I added
>external DRAM.
>
>What isn't possable, moving data around on the HD?
>We aren't talking about reading 4MB into memory and
>writing it back out again, just reading a sector (or
>some part of it), and writing it back out in a new
>location, over and over.
>
>How much memory does the AVR have without adding
>external DRAM?
>
>DK
>
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