Re: [stella] AtariVox EEPROM file format

Subject: Re: [stella] AtariVox EEPROM file format
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sat, 27 Nov 2004 22:31:37 +0100
The original format just specified 8 bytes for a filename with the 7th bit
in the first byte as an indicator to whether the 128 byte block is used or
not.  We've been debating changing this format a bit.

The VCS isn't really an ASCII machine anyway, so there isn't really a need to use 8 bits per character. If we could agree on a 5 bit and a 6 bit character list, we could use a naming scheme like this:

Use two bytes for the file type with 5 bits for each character,
and use 6 bytes with 6 bits for each character for the file
name. That way you would get the 8+3 (or rather 3+8) DOS style
file naming format and still have 1 bit left in the file type
bytes to indicate if a block is used or not. And you wouldn't
even use more than the 8 bytes from the original suggestion.

DOS only has 52 different characters for naming files, so
we would only be more limited than DOS for the file type.
But I don't think that would be much of a problem, since
most people would use letters for theiry like type names

The encoding routine for the names would have to be a bit
more complicated than with real ASCII characters, but since
the VCS dosn't have ASCII inputs anyway, that isn't much
of a problem.

Once the name is encoded, searching for a type or a file
name is just a complex as with ASCII characters, so no
extra work there. And since the file type and the file name
are seperated, finding all files of a certain type is
quite easy too. And managing files with a maintainance cart
would be easy too, since everyone could easily see which
file type belongs to which game.

Now we only need to agree on a 5 bit and 6 bit character list.

The other issue is: should programs be able to delete other program's file
types? Alex thinks they should, but I think they shouldn't. I think that
there should be a 4k program (that can run on the Supercharger) that can
maintain the memory and delete/move/etc files. But not everyone may have a
supercharger. Yet I don't really want to have to use extra space in my
program to include the ability to delete other program's files.

The AtariVox will be sold by AtariAge soon. So the Als probably will be able to offer a cheap maintainance cart in a bundly with the AtariVox too. Therefore the need for the Supercharger isn't much of a concern.

And while I don't think games should be forced to offer file
management for all types of file, I think they should be allowed
to let the user manipulate files from other games too, if they
want to.

Ciao, Eckhard Stolberg

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