Am 11 Aug 2004 14:47 meinte Steve Thatcher:
> I realize that the idea is to create a format to make re-creation
> of media possible for a variety of platforms. We can certainly do
> that and have its only function be to maintain a physical data
> format. My added idea is that the data and the formatting be
> separated so that a simple utility on a non-target platform could
> extract data from the image file.
Well, physical format and data is not always seperable. In some
circumstances the physical format is part of the onformation an
application needs, and differs form media to media (e.g. copy
protection schemes)
> If we create a physical description only and do not abstract
> the data then any emulator must understand the OS file
> structure in order to retrieve any internal file representation.
> My idea would make the file re-creation simple in that the xml
> image file would be parsed for the actual file data that an
> emulator would need. This makes the emulator easier.
But what if the emulator needs the physical format information?
> To retrieve a file from the physical layout that it at the end
> of this message, the emulator must know the actual disk format
> that is used on the target system (the one the image file was
> made for). I have seen cp/m systems where the actual physical
> sectors were sequential on disk and the OS file sector was
> actually virtual to increase speed. Not my idea of the way to
> do it. It is much easier to make the physical sectors slewed
> so that a physical sector is a file sector. These are the types
> of issues you will have to overcome if an emulator must totally
> understand each and every file system for a cp/m version for
> example.
At least within a CP/M system it usualy doesn't matter at all
how the files are stored on a disk. Except for some odd apps
who tried to implement system specific copy protection schemes,
all and every CP/M app accesses files just via BDOS which already
hides the real disk strukture.
Gruss
H.
--
VCF Europa 6.0 am 30.April und 01.Mai 2005 in Muenchen
http://www.vcfe.org/
Received on Thu Aug 12 2004 - 09:06:02 BST