v6 with two DL11s now works ... silly me!

[Bob Manners]

I've recently been deluging the list with problems and obseervations
concerning the v6 kernel. Most recently, I discussed the putchar()
routine in /usr/sys/ken/prf.c, which prints messages only if the front
panel switches are set appropriately. I modified that routine by
commenting out an if, so the messages would always be sent to the
console regardless.

Having edited prf.c and rebuilt the kernel, I was suprised to find no
change in the behavior on bootup. Comparing the 'new' and 'old'
kernels (with cmp) showed them to be the same. The problem then is
that the kernel was not being rebuilt correctly.

Accordingly I removed all .o files, and the files /usr/sys/lib1 and
/usr/sys/lib2. I rebuilt again. The lib1 and lib2 files do not build
directly from the /usr/sys/run script, but rather use "ar r" to
replace the files in the libraries with the newly-built object
files. Thus I had to manually build the libraries. NOTE: it is
important to get the object files into the library in the correct
order -- I simply copied the order as for the distributed files... 

I remember using tsort and lorder for Minix to determine library
component ordering, but I forget how that works ;)

Having rebuilt everything, not only did the messages print, but also
the second KL11 magically worked. Thus what I had been doing all along
was OK, but the kernel was not being properly built using all the new
object files.

Summary - to set up a second DL11 (configured as the first "local"
interface):

	1) ed /usr/sys/dmr/kl.c 

			changing NKL11 to 2 

	2) modify /usr/sys/run to call mkconf with the additional 
	   parameter:

			1kl

	3) Bob, so to speak, is your uncle.

Be sure everyhing is rebuilt. 

I wonder if there is a bug in "ar r", whereby certain files fail to be
inserted into the library, so that old versions persist. Using the "ar
rv" verbose option may be wise ...

Hope this info is useful to those mad enough to want to use v6 ;)
Thanks for all your help. 

Next project --- port the v7 shell to v6. Hmmmmmmmmm.


Bob

-- 

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Robert Manners                                  Osney Laboratory
rjm at swift.eng.ox.ac.uk                          Dept of Engineering Science
                                                University of Oxford
                                                01865 288762
Try: http://swift.eng.ox.ac.uk                  Linux - the only choice

       "I'd rather stay a child
        and keep my self respect,
        if being an adult
        means being like you"   Jello Biafra
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