[comp.sys.sun] Sun 3x <==> Sun 3 compatibility

adoyle@bbn.com (Allan Doyle) (08/29/89)

Scenario:

	We have a Sun-3/280 based system at a customer site.
	We want to install a second system at the site.
	In order to give the customer a performance bonus, we 
	  want to upgrade to a 3-3/480.
	Our customer has spares for the 3/280 and does not want
	  to pay for a spare 3/480 CPU.

	We say "No problem, use the 280 spare as a fallback and
	the second system will run, albeit a little slower."

Problem:
	When I plug a 280 CPU into the system from which I have
	pulled the 480 CPU, it does not boot. I have, of course, already
	copied a kernel built on a 280 system into the root partition.
	The boot program gives up right away because of a page mapping
	problem.

Obviously, I'm getting bitten by boot code that was configured for a 68030
with native MMU, or am I? What is going wrong here? How do I fix it?  Once
I get the sucker to boot, what else is going to bite me. I noticed a bunch
of symbolic links in /usr/shar/mdec that are CPU specific.

The real question is: How do I put the 280 CPU into the system with the
shortest turnaround? The path of doing a new installation of 4.0.3 each
time I swap CPUs will probably work but takes too long. (The client after
all, likes short repair times...).

Any ideas you folks have will be welcome. I will post a summary and if I
get a good procedure, I'll post that as well.

	Allan Doyle


Allan Doyle                                              adoyle@bbn.com
BBN Systems and Technologies Corporation		 (617) 873-3398
70 Fawcett Street,   Cambridge, MA 02138

poffen@sj.ate.slb.com (Russ Poffenberger) (09/20/89)

In article <1232@brazos.Rice.edu> adoyle@bbn.com (Allan Doyle) writes:
>X-Sun-Spots-Digest: Volume 8, Issue 109, message 8 of 12
>
>Scenario:
>
>	When I plug a 280 CPU into the system from which I have
>	pulled the 480 CPU, it does not boot. I have, of course, already
>	copied a kernel built on a 280 system into the root partition.
>	The boot program gives up right away because of a page mapping
>	problem.
>

Did you copy the correct version of /boot onto the hard disk? This is the
actual boot code. Also after copying, you must do an installboot on it (if
4.0.x, you didn't specify) to make it work.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
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San Jose, Ca. 95110
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