Subject: Re: Performa 6200 upgrade path query
To: Roger Brown <>
From: David A. Gatwood <>
List: port-macppc
Date: 06/21/2000 12:21:38
On Thu, 22 Jun 2000, Roger Brown wrote:

> Apart from the Performa 6200 running 8.1, I have a 586 running Slackware
> 3.3 and a MacIIvx running NetBSD 1.4.2. 

Sounds a little like my dorm room, only substitute a G4 for the 586 and a
Q800 for the IIvx.

> For the 6200 I have an external 500Mb SCSI drive which might be useful, as
> well as internal 500Mb IDE.

Well, I can tell you right now that the IDE will work sooner than SCSI. 
IDE on these machines is so simple, that it takes all of two lines of code
to support a new machine.  SCSI... well, the Performas use the same SCSI
chip as the later machines (thank heavens), but they do so without DMA,
which is contrary to the MkLinux driver's expetations.  I've hacked the
driver where I think it might work sans-DMA< but I would expect it to put
up a fight before it starts working.  ;-)

> Considering mklinux is a linux, would I be able to do cross compiles on
> the 586? 

In theory, but I'm not sure how.  The work needs to be done in the Mach
Kernel, which is rather a pain in the backside to build without
cross-compiling.  :-/

> If so, what do I have to do to help?

Once I get the thing to start booting, I can think of a lot of things.
Right now, it's a matter of fixing the BAT code, and I know approximately
when that code broke, so... a good task for someone would be to just pull
the current source tree from CVS and then pull revision and diff
the two, or at least the early startup files.

> I am very happy programming in C on UNIXes, know 68000 assembler, no PPC.
> Knew to kernel programming, but I have done some device driver work on other
> platforms.
> Err, what's 'BAT'?

Block address translation.  Used for mapping large regions of memory.
There are only a handful on most processors.  PPC has... 4 for
instructions, 4 for data, generally.


A brief Haiku:

Microsoft is bad.
It seems secure at first glance.
Then you read your mail.