SD: Re: VAT/FAT DH85
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SD: Re: VAT/FAT DH85
Hey thanks for the help. As for the file system, I just talked to kaus
he said, we will implement a FAT style file system.
I had an idea, instead of having a 36K block of data pointers, why not
just have a pointer at the last byte on a page to tell the OS where the
next block is (or 0 if there is no more to the file). That would
definantly reduced that wasted space. There are 2 ways of implementing
the directory stucture:
1) There could be a directory table, as you suggested, with a table that
has all the names and the blocks thery start at , or
2) The first byte of each block could tell the OS what kind of block it
is: start of file, data, EII info, ect.
Any comments?
Matt Butch
mjb25@hotmail.com
Member of the The Doomsday Horizons Administrative Committee (DHAC)
>From: yakko@ravine.binary.net
>Date: Thu, 20 Aug 1998 11:14:32 -0500 (CDT)
>To: mjb25@hotmail.com
>Subject: VAT/FAT DH85
>
>I meant the mmethod for storing stuff on the E2, not the calculator.
>
>As I see it, using a VAT style file system will seriously degrade the
>life of an E2 (excessive writes) because a VAT expects the entire
>file to be in contiguous blocks, in a VAT the file is referenced by
>a starting location, and a length. A FAT system would make the E2
>more harddrive-like (?) in that if you add on to a file, you don't have
>to rearrange everything on the E2 to make that one file be all
>contiguous blocks. Instead, in a 512k E2 space, you'd need to allocate
>E2 space in blocks of say 256 bytes (more or less, not important right
now)
>and have a 36k "table" telling the program where in the E2 the next
block
>in the file is. Also, something akin to a Directory Table would be
needed
>to find where the first block of the file is hidden. One drawback to
>the FAT system is it's need for, like I said, 36k of space when using
>256 byte blocks. The block size could be raised to 512 bytes and that
>would shrink the FAT table by half, but a file would take up a minimum
>of 512 bytes regardless of the actual size.
>
>Internally in the calculator, or course we'd have to use the VAT system
since
>anything else would be a pain to implement, and pretty much pointless.
>
>Anyways, after reading all that bs I just spouted, let me know what you
>are planning to do about the file system.
>Thanks,
>Jim
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