[Coco] data modules

[Dave Philipsen]

I don't think there's really much to a data module other than setting 
the attributes correctly.  It's purpose would be to share common data 
among multiple processes.  The format of the data module would be 
entirely up to the creator of it.  As long as all processes that will 
use the data module understand the format then the data is organized in 
any way you want and each process would know how to access it.

In Peter Dibble's notes he states that a rather annoying problem with 
data modules is that they must always be loaded from disk as there is no 
method for a process to create a memory module. However, by the time 
version 2.3 rolled around (OS9/68k) there was a system call where a 
process could actually create a data module without actually loading it 
from disk.

One other note of interest is that for a data module to be used by 
multiple processes it would have to have to be made  're-entrant'. 
Usually, that term would imply re-entrant executable code but in the 
case of a data module it would allow the system to map that module into 
the address space of multiple processes that may link to it. In Level 1 
this wouldn't be necessary as everything is done within the confines of 
64k and there's no MMU; a link to a data module would just retrieve the 
location of that module in the 64k address space.  However in Level 2 
the system must manipulate the MMU for every process that links to the 
data module so that it is mapped into that process' memory space.

Dave


On 6/9/2017 6:54 PM, Stephen H. Fischer wrote:
> While searching for Datamod I found it where I should have looked first, the one place stuff from Delphi / CI$ might be.
>
> 1998
> ftp://www.rtsi.com/OS9/OS9_6X09/APPS/datamod.lzh
>
>
> 1994
> ftp://www.rtsi.com/OS9/OS9_6X09/APPS/DataMod.lzh
>
> IZArc will open the lzh files on Windows 7.
>
> SHF
>
>
> ----- Original Message -----
> From: "Wayne Campbell" <asa.rand at gmail.com>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Friday, June 09, 2017 12:33 AM
> Subject: Re: [Coco] data modules
>
>
>> Tell me where to look, Stephen, and I will search for it.
>>
>> On Thu, Jun 8, 2017 at 8:33 PM, Stephen H. Fischer <SFischer1 at mindspring.com
>>> wrote:
>>> Here is one example I used a lot.
>>>
>>> Problem, Shellplus will not pass parameters like you can with a normal
>>> text script.
>>>
>>> ------------------------------------------------------
>>> DataMod v1.1 (c)1988 by Ron Lammardo
>>> Shellscript/Data Module Conversion Utility
>>>
>>> Syntax:
>>>     datamod {modname} <{pathin} >{pathout}
>>>      Takes a shellscript from the standard input path and converts
>>>      it to a Data Module written to the standard output path.
>>>      The {modname} will be used as the module name.
>>>
>>>     datamod -<{pathin} >{pathout}
>>>      Takes a Data Module from the standard input path and writes
>>>      it to the standard output path as a shellscript.
>>>
>>>     datamod -m {modname} >{pathout}
>>>      Takes a Data Module in memory and writes it to the standard
>>>      output path as a shellscript.
>>>
>>> ------------------------------------------------------
>>>
>>> I have the Delphi posted version likely from 1988-1989.
>