ARMLinux and NetBSD

29/06/00 Update:
succesfully recompiled linux 2.2.13 kernel for the RiscPC.
"Somtimes it pays to sit back and think for a while, the kernels on the netwinder
seem to popup like mushrooms, why can't ... Use the Source Luke..."

started a History file.
"Maybe someone outthere might like to know what has happend.. "

    To make a small study of the unices available for the SA110 I have been looking at ARMLinux
and NetBSD (formerly know as RiscBSD).


    The build for the Netwinder of ARMLinux originates from the one from Russell King. Russell has
done most of the work to get Linux working on the ARM and on the Acorn range computers.
The latest in that range is the RiscPC-SA which has a SA110 at the heart of it.
It uses 'old-style' EDO RAM but has a nice flat memory-model for fast graphics.
The efficiency of the D and I cache compensates nicely for the lack of memoryspeed.
I was curious how it would perform with respect to the Netwinder.
I still have not done benchmarking , the gcc-compiler is somewhat broken. ( ELF support
and ARMLinux on the RiscPC is somewhat a novelty. Russell has no support for making ELF
binairies with gcc on his ARMLinux webpages.) .
For a brief tour through my efforts in ARM and linux view the History page.

getting it done:

To get things up and running I installed a bootloader from the RISCOS parts of ARMLinux and
got the files to install ARMLinux on a RiscPC. Unfortunately the setup for the RiscPC fails horrably
in not being able to unpack the rpms. The skeleton and /varsettings seem to fail and eventually
adding new users or setting passwords does not work... The user and group information was garbled
leading to an unmaintainable mess with loads of files owned by the wrong groups or even by non-
existing groups.

There is however a way of getting around the trouble.
Somewhere else on the web there is a description of how to use the Clan CD (Acorn related) to install Linux.

When I got my RiscPC to produce a login prompt I decided to upgrade all the binairies
with ones from the DM-12. Some worked others failed. Most of them just failed because of the
wrong location of 'ld'. After adding a softlink to the right ld it seemed fine. For a while ...
The LDH and STH instructions will fail on a RiscPC because of lack of hardwaresupport.
This only occurs when the data is not in the cache however. The instructions are rare but do
make the system unstable...

the experiment:

I tried to boot a DM-15 partition on the RiscPC but this fails with loads of errormessages and
it seems that the init script needs more than just a 2.2.7 kernel available. Most likely the hardware
is not compatible enough to run the DM-15 image.
(somuch for that experiment.)

another try:

I have now installed RiscBSD on the RiscPC. ( Peter Berg has a SVGAlib compatible library!)
If ARMLinux for the RiscPC would have a SVGAlib then I might stick to ARMLinux and try to complete
the pain of porting all the stuff of the Netwinder to the RiscPC...

Peter Berg has mailed me a bootloader for RiscBSD on the RiscPC and I was all set to go.

"I never knew that BSD cannot read ext2 file partitions...."

Luckily I got it all working. The bootloader is quite nice and even has a 'mbr' feature. Once on my way
I learned that instead of using rpm -i I needed to do pkg_add(where was that manual you said??).

rule of thumb:

I decided to look at the debian image file for the RiscPC and install the tar.gz file on a small partition.
Very interesting ... Init got stuck somewhere. Reboot.. same thing happened.
Reboot with init=/bin/bash ... OK. what the hell went wrong. let's look at inittab. hmmm .. where is it..
Ok, lets fix fstab instead. Rather unlikely that this image is set to /dev/hdb5 as root and /dev/hdb4 as
swap. Sync ... Reboot ... Init runs ... runs... fsck runs... ( GOOOD... )  .. hangs..
Brilliant thought : <ctrl>-C.
Init got through and I got a prompt. That was easy... . Now the hard part. Login as root, password...

eeerr...  <enter> ...  GREAT !!!

Exciting half hour... but : It WORKS !

this shows : Keep it Simple Stupid !    -KISS-   , rtfm...

on with the quest:

Peter Berg has mailed me that I could continue the development of his libmultimedia. This would be
nice because on the 1.4.2 kernel ( NetBSD ) the support for the mouse has probably changed. At
least the svga version of libmm does not work anymore with the mouse.
It seems that debian also has a svgalib for the RiscPC and that just might allow me to do some testing.
Afterall it is my 3D software that I would like to compare on the two different platforms.

Jan Rinze