🚀 go-pugleaf

In article <phil.656040612@adam.adelaide.edu.au>, phil@adam.adelaide.edu.au (Phil Kernick) writes:
> In article <291@geocub.greco-prog.fr> anthes@geocub.greco-prog.fr (Franklin Anthes) writes:
> -
> -I'd really like to find an amiga device (comp:?) which would automatically    
> -compress/decompress any files stored on it. I don't think such a device would 
> -be able to handle direct access ( it could probably fake it though ). But     
> -it still would be a really usefull tool.                                      
> 
> Isn't this basically how an RLL hard-drive controller on an I*M works?
> As I understand it, it run-length encodes the data to be put on the
> hard drive before storing it, and decodes it when reading it off.
> 
> This would mean slightly slower access times, but an increase in disk
> capacity of about 50%.
>

 Not quite. RLL and MFM are just two different ways of encoding separate bits
in a stream of them. The RLL gives higher densities, simply because it has a
diffent number of transitions for a given bit pattern than MFM, and so can be
recorded at a higher density.

MFM is also an example of RLL encodeing, however the method is slightly
different, and so the number of transitions written to the substrate is
different.

For a complete explanation see BYTE magazine. They had a piece on encoding bits
on disk substrates not too long ago, however I can't remember the issue off
hand. (any body?).
 
> Phil.
> -- 
> Phil Kernick                            EMail:  phil@adam.adelaide.edu.au
> Departmental Engineer                   Phone:  +618 228 5914
> Dept. of Psychology                     Fax:    +618 224 0464
> University of Adelaide                  Mail:   GPO Box 498 Adelaide SA 5001
-- 
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