Path: utzoo!attcan!uunet!mcsun!hp4nl!star.cs.vu.nl!sreiz
From: sreiz@cs.vu.nl (Reiz Steven)
Newsgroups: comp.sys.amiga
Subject: Re: MINIX on the Amiga...
Summary: to shed some light on a possible misconception:
Message-ID: <7756@star.cs.vu.nl>
Date: 27 Sep 90 13:40:42 GMT
References: <7726@star.cs.vu.nl> <1990Sep24.114627.14857@watserv1.waterloo.edu> <1990Sep26.141624.27304@funet.fi>
Sender: news@cs.vu.nl
Lines: 62

In article <1990Sep26.141624.27304@funet.fi>, mk59200@korppi.tut.fi (Kolkka Markku Olavi) writes:
(about Amiga Minix)
> 
> It doesn't save the autoconfig information???
> Then there is no hope that you can use hard disks or extra
> serial cards with Minix!!  Is somebody working on fixing this
> braindamage?

You are absolutely right about the problems you named; no harddisks or
extra serial cards. BUT ... don't forget what minix is: it is an operating
system! 
When amiga minix is started is saves some information from the old
AmigaOS, for example how much ram you have and at which addresses it is
located, and then it kicks out DOS, Exec, Intuition and all the other
parts of AmigaOS and starts running itself. 
That means that it can't just call Open("SER:", 1006L) to open a
serial port. It has to find out where the uart is in the memory map 
($df0xxx in this case) and start poking in the registers,
just like those German hackers do in their assembly programs :-)
That is the reason why those hacker programs are not popular: soon someone
will have a configuration where this 'blind poking' doesn't work and will
crash his/her machine.
That is also the reason why it is so !@#$% hard to write a good operating
system, specially on the amiga where all hardware manufacters supply custom
drivers with their harddisks and extra serial cards. These drivers CANNOT be
used by minix because they all use Exec message passing or DOS packets etc.
etc.
This means that for a new operating system, like amiga minix, all those drivers
will have to be recreated, using the appropriate minix kernel primitives
instead of Exec messages and DOS packets.
This means that eventually, just as is the case for ST and PC minix right now,
zillions of drivers for various harddisks etc. will have been written, but 
in the mean time drivers for hardware that is used a lot (e.g. SCSI harddisks)
will have priority over drivers for hardware that isn't used a lot
(e.g. extra serial cards).
We as minix developers can't go out, buy all possible amiga peripherals
and start writing drivers for them (much as we would like to!) because there
are simply too many different peripherals. 
So ... we did save the autoconfig information about ram, because we did have
ram (wauw!) to test it with, but we didn't save the autoconfig information
about harddisks, because we didn't have a harddisk (we crosscompiled on an
atari ST running minix 1.1). This made it very hard (read impossible) for
us to find out what kind of information to save about harddisks, where we
could find this information and what to do with it from within minix once we
had saved it.

If anyone has information about amiga harddisks on the 'hardware reference 
manual' level I would sure like to hear from him/her! I imagine that this 
inhformation would be something like:
Well, for harddisk XYZ you have this address, $da0010 where you put the 
address of the buffer in which you want to read, and this other address,
$da0020, where you write a 1 and bang! your harddisk reads the data
and puts it in the buffer. 
Of course a lot more information is needed, about partitions, cylinders,
heads, sectors etc etc...

I hope this helped to clarify why minix doesn't support extra serial cards,
tape drives, cd rom drives, graphical tablets or even harddisks yet.

Regards,

                    Steven Reiz