
______  GHOST.PRG  _____________________________________ 01 Mars 1992 __


   Formatter and copier for ALADIN, SPECTRE and MACINTOSH diskettes.

                           Author: Miguel SARO


NOTICE: The author has placed this programme in the Public Domain in the 
        hope  that  you  will find it useful,  but he  cannot  give  any 
        guarantee  as to its reliability (in other words use it at  your 
        own  risk).  It was developped using SOZOBON C and  GULAM  (many 
        thanks to their respective authors).  No version number has been 
        assigned to it, simply a creation date it used.


    The  programme is mainly aimed at SPECTRE users who wish to  convert 
files  from  the now defunct ALADIN format.  Although SPECTRE  3.0  (the 
latest  version  at the time of writing) allows you to read the  old  9-
sector 696k ALADIN discs directly under MAC emulation this is only  true 
if your MAC system does not reside on a SPECTRE-format floppy (as is the 
case  for  SPECTRE  128 owners without a  hard  disc).  SPECTRE  becomes 
confused  between the 9 and 10 sector formats that it has to  deal  with 
simultaneously.  So  ALASPEC  (the  predecessor to GHOST)  was  born  to 
convert between the two formats under GEM.
    The  problem  of  exchanging  files  between  SPECTRE  128  (no  GCR 
capability) and a real MAC, however, still remained. GHOST resolves this 
by  making use of the fact that all MACs with High Density drives  (e.g. 
the MAC Classic,  MAC LC,  MAC II's etc) can handle discs written  using 
MFM  (Modified  Frequency Modulation) so that MS-DOS discs can  be  read 
using Apple File Exchange.  It just so happens that if the MFM  diskette 
contains a valid MACINTOSH file structure (MFS or HFS) then it can  read 
and  written directly by the MAC.  The diskette does however have to  be 
formatted  using 9 sectors per track (720k max) with  information  being 
successively written on one side and then the other as each track  fills 
up.  SPECTRE-format diskettes do no however use this  arrangement,  they 
first  fill up one side of the diskette and the fill up the other  side, 
as well as having 10 sectors per track (800k max).
    GHOST  converts diskettes between these two formats.  Obviously  you 
cannot squeeze a 800k SPECTRE diskette into a 720k MFM diskette,  but if 
the  top 160 sectors of the SPECTRE diskette do not contain  any  useful 
information nothing will be lost in the conversion. You can usually make 
sure this is true. Should individual files be too big to be contained on 
a  720k  diskette  they can split into two or more  smaller  ones  using 
something like Stuffit.
    What  follows is a very brief list of the capabilities of GHOST  but 
should be sufficient to use it without any trouble.


____Format Information:

Only  double-sided  MFM diskettes can be handled by GHOST  which  treats 
them according to their physical structure rather than their contents:

        __TYPE___|  tracks  sectors     organisation     capacity
         ALADIN  |    79       9     alternating sides     696k (1)
         MAC_MFM |    80       9     alternating sides     720k
        ALADIN v3|    80      10     alternating sides     800k
         SPECTRE |    80      10      successive sides     800k

(1) - The first track on each side is reserved for GEM.

____Settings:

        Drives : A, B(if it exists)
         Types : ALADIN, Mac_MFM, ALADIN version 3, SPECTRE
    Capacities : 696k, 720k, 800k.
         Modes : MFS(Macintosh File System), HFS(Hierarchical File System)

____Operation:

    Start  the  programme under GEM in the usual way (it  does  not  use 
    either  of the emulators).  Click on the various boxes shown in  the 
    display window to correspond the the required operation.

    For "COPY" and "FORMAT & COPY"
        You have to chose the structure of the source diskette and  that 
        required  for the destination.  The capacity of the  destination 
        has to be limited to that of the source.

    For "FORMAT"
        You have to chose the structure of the diskette to be  formatted 
        as well as its capacity and logical organisation.

        If you click on the "?" for either of the diskettes it will  try 
    to  determine  the  structure  of  that  diskette.  If  it  displays 
    "ALv3_SPct"  it  means that it cannot tell whether it is  an  ALADIN 
    version 3 diskette or a SPECTRE diskette.

    Click on the operation to be perfomed.

        The programme will never refuse the requested operation, but the 
    result obtained depends on how accurately the settings were  chosen. 
    It  is  possible to copy a SPECTRE 800k diskette to  a  696k  ALADIN 
    one!!  - you will lose the excess and the MAC system will ask you if 
    you want repair the diskette.

    
        The programme has dialogues in both English & French (since  the 
    author is French):

____To change language: (French/English)

    While running     : click  on  "Help/Aide" at the top right  of  the 
                        window  then on "Continue",  on the next  screen 
                        click on either "Francais" or "English" to chose 
                        that one. Click on "Return/Retour"
    Changing default  : while  on  the second  screen  described  above, 
                        clicking  on "set default lang." will  save  the 
                        current setting to the programme itself so  that 
                        it  will be this language used when it  is  next 
                        re-started.

___ I wish to thank my friends:  Yves LAGARDE for his suggestions  after 
    testing  and  Paul  DAGLEISH for the same reason but  also  for  his 
    translation into English of the programma dialogue and this documen-
    tation (you're welcome - PD :-) ).

___ If you have any comments or wish to contact me please write to me at 
    the following address (I don't have access to the net) :

            M. SARO
            Help Informatique
            7, rue de Strasbourg
            38000 GRENOBLE
            France.

