RFC

[Julian Reschke <reschke@GOEDEL.UNI-MUENSTER.DE>]

RFC: TOS compatible software running on foreign hardware (Nov 5 1994)

Some people might already have heard that there'll soon be a TOS 
compatible operating system running on Mac-68-Hardware: MagiC is currently 
being ported to the Macintosh platform.

For application and library developers, there are some issues to look for. 
Below are some of them (actually those I could think of right now):

(1) Probing for OS features: NEVER use version numbers when there's a 
defined return code for non-existant calls. Example: 
Dopendir/Dreaddir/Dclosedir can be used on MagiC 3.0, MetaDOS 2.40 
(form some devices only) and MiNT -- not only on MiNT.

(2) Cookies. Unfortunately, there are two cookies signaling hardware 
features which haven't a value for 'not applicable'. In particular, a 
`_MCH' cookie value of 0xFFFFFFFF should be interpreted as `this is not an 
Atari Computer, don't make any assumptions about hardware features and 
don't touch I/O registers). The same applies to `_VDO'. Note that `_SND' 
is not a problem, because it's defined as bitset.

(3) Machine type: vendors of new hardware platforms for TOS compatible 
systems should set a `MNAM' cookie, which should point to a 
zero-terminated ASCII string (max. 24 characters + '\0') describing the 
hardware (like: `Atari TT030'). This is what the POSIX utility `uname' 
should display when called with the option `-m'.

Note that I'm not directly connected to the people working on the project; 
I'm just trying to clear things up as early as possible. And: don't ask me 
about more details right now; it'll be there sooner than you think :-)

Comments to: jr@ms.maus.de



-- 
---------------------------------------------------
Julian F. Reschke, Hensenstr. 142, D-48161 Muenster
 eMail: reschke@math.uni-muenster.de jr@ms.maus.de
___________________________________________________