This file describes the steps neccessary to access a JanusTools hard disk
partition using CrossDos.  You may also be able to use other MS-DOS file
systems, such as MessyFileSystem.

1.  Set up the partition you wish to use with the Bridgeboard or PC-Task
    on your Amiga hard drive according to the JanusTools documentation
    *except* you must set the DOSType for the new partition to 0x4D534400
    *not* 0x4D534800 as stated in the JanusTools documentation.  CrossDos
    will not work with the 0x4D534800 DOSType, but JanusTools will work with
    the 0x4D534400 DOSType.  This should be possible to do with HDTools
    or the utilities that came with your Amiga hard drive.

2.  Obtain PCDISK91B (from Aminet).  In it is a utility called DISKINFO.
    Run DISKINFO to obtain the Mountlist parameters for the JanusTools
    drive.  It is best to redirect this to a file so that it can be imported
    into your Mountlist.  I use something like: DISKINFO DH2: >DH2.PARMS.

3.  Add this entry (DH2.PARMS in my case) to the end of your Mountlist.
    The Mountlist usually resides in SYS:DEVS/Mountlist  (where SYS: is the
    boot partition and usually a hard drive, but could be a floppy).

4. Modify 5 of the parameters in the Mountlist entry that you just added for
   the JanusTools partition.  Change the name of the entry.  If it is DHx:,
   you can change it to something like IBMC:, IBMD:, or whatever.
   Change the DosType parameter to 0x4D534400 (but, it should already be set).
   Now the entries for LowCyl and HighCyl should be modified according to
   the formulas (taken from PCDISK91B):

   NewPCLowCyl = (AmigaLowCyl * Surfaces) + 1
   NewHighCyl  = (AmigaHighCyl + 1) * Surfaces) - 1

   where AmigaLowCyl is the LowCyl parameter of the unmodified Mountlist entry
         AmigaHighCyl is the HighCyl parmater of the unmodified Mountlist entry
         Surfaces is the Surfaces parameter of the unmodified Mountlist entry

   Replace LowCyl and HighCyl with these values and replace Surfaces with 1.

5. Add a parameter entry (or change any existing one for FileSystem):
   FileSystem = L:CrossDosFileSystem (or L:MessyFileSystem)

6. If you plan to use this partition with any of the various Bridgeboards,
   you will need to edit the ABOOT.CTRL file which is usually in the PC/SYSTEM
   drawer.  Put in this file the name of your PC partition (i.e IBMC:, IBMD:
   etc.)  Be sure you have the ":", but do not put a carraige return (newline)
   at the end.  Thus, you should have one line only in the file.

7. Now, when you boot your Bridgeboard, you will have to go through the usual
   steps to initialize and format the new partition.  Please see you MS-DOS
   documentation if you are not familiar with this.

8. If you have done everything correctly, you can now Mount this entry (add
   a statement in your startup-sequence such as MOUNT IBMC:) prior to
   invoking the Binddrivers command to boot the Bridgeboard and when you
   do a DIR on it from AmigaDOS, you should see the PC files.  You should
   also be able to add this entry as a primary (C:) or secondary (D:) hard
   disk entry in the PC-Task startup menu and access it when in PC-Task.
   If you have problems or are reading garbage, go back and carefully
   check the parameters.

As an example, I have an IBM 728 MB IDE drive partitioned into
DH0: (200 MB), DH1: (200 MB), DH2: (200 MB) and DH3: (99 MB).  I used
DH2: as my PC DOS partition.

My DH2 entry (from DISKINFO) looks like this:

DH2: Device          = ExpSys.device
     Unit            = 80
     BlockSize       = 512
     Surfaces        = 16
     BlocksPerTrack  = 63
     Reserved        = 2
     PreAlloc        = 0
     Interleave      = 0
     LowCyl          = 818
     HighCyl         = 1224
     Buffers         = 32
     BufMemType      = 1
     MaxTransfer     = 0x7FFFFFFF
     Mask            = 0x00FFFFFE
     BootPri         = 0
     DosType         = 0x444F5301
#

My JanusTools PCE entry (modified from DISKINFO) looks like this:

PCE: Device          = ExpSys.device            ;<- changed
     FileSystem      = L:CrossDosFileSystem     ;<- added
     Unit            = 80
     BlockSize       = 512
     Surfaces        = 1                        ; <- changed
     BlocksPerTrack  = 63
     Reserved        = 2
     PreAlloc        = 0
     Interleave      = 0
     LowCyl          = 13089                    ; <- changed
     HighCyl         = 19599                    ; <- changed
     Buffers         = 32
     BufMemType      = 1
     MaxTransfer     = 0x7FFFFFFF
     Mask            = 0x00FFFFFE
     BootPri         = 0
     DosType         = 0x4D534400               ; <- changed
#

My ABOOT.CTRL has PCE: and I can access PCE: from the Bridgeboard, if I
disable my PC IDE drive via the CMOS settings, or I can access it from
PC-Task, or I can access it via AmigaDOS (CrossDOS).

Jordan Krim
krim@vnet.ibm.com
krim@azstarnet.com