Message-Id: <s47d865a.055@calderauk.com>
Date: Thu, 27 Nov 1997 14:40:05 +0000
From: Matthias Paul <MPaul AT calderauk DOT com>
To: opendos AT delorie DOT com, paul-ma AT reze-1 DOT rz DOT rwth-aachen DOT de
Subject: Re: Multiple Configurations
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On 97/11/27 Philip Lettkeman asked:
>I just installed OpenDOS the other day over a Multiple Configurations
>MS-DOS 6.22.  
>I guess OpenDOS doesn't like the multiple configurations?  Does anyone
>know how to do menus from the config.sys to set up a multi in OpenDOS or
>is this even possible?
It is possible, OpenDOS actually provides a CONFIG.SYS language, which
is - though different - similar to BASIC or the batch language in many respects.
You have full flexibility to create menu systems etc. using DR DOS 6.0+ 
directives like ECHO, SWITCH, GOSUB, RETURN, and many more...
(Note, that this menu style was introduced before the MS-DOS boot menus.)

Since my IBMBIO ALPHA1+ and COD 7.02 B2+ the possiblity to use one CONFIG.SYS file for both system has been greatly improved. While still
maintaining it s own set of CONFIG.SYS directives, IBMBIO now also accepts
virtually any directive ever been used for MS-DOS or PC-DOS, including new
directives used by Windows95. Most of them are fully functional, but a few have
no reasonable expression under OpenDOS, for syntax compatibility these are
just handled as aliases to REM. There is one exception of this rule, and this is 
the boot menu syntax and special directives for boot menus.
 
To understand this, one needs to know, that the internal approach of processing
CONFIG.SYS is completely different between the DR DOS and the MS-DOS
family. Under DR DOS, the file is interpreted, and under MS-DOS it is compiled
in some way. This gives our implementation much more flexibility (for example
in the loading order of drivers), but can also confuse some users, being used
to the MS-DOS style. Especially for process control directives like boot 
menus it is very difficult to emulate the other style with the own implementation (bothways).

However, it is possible to emulate the MS-DOS style by using our directives
(even %CONFIG%, just use SET CONFIG=cfg), so that the general block structure remains equal. Though it is preferrable to maintain the configuration
in different files, you also can put all the OpenDOS configuration in a MS-DOS style group like for example [OpenDOS], which must not be used by MS-DOS  boot menu itself. MS-DOS should than ignore these directives. A problem is to 
force the execution of this block under OpenDOS, since the processing starts in line 1. Again, since COD 7.02 B2+ you can by using its enhanced CHAIN=, e.g.

CONFIG.SYS 

[menu]
... MS-DOS menus
... MS-DOS stuff
[OpenDOS]
:opendos
... OpenDOS menus
... OpenDOS stuff
:common
[Common]
... common stuff

DCONFIG.SYS: 
(forces OpenDOS  execution of group [OpenDOS] in CONFIG.SYS)

CHAIN config.sys, opendos


------------------------------------------------------------
Matthias Paul
eMail: <Matthias DOT Paul AT post DOT rwth-aachen DOT de>
Web: http://www.rhrz.uni-bonn.de/~uzs180/mpdokeng.html