From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 25 Oct 1996 23:42:07 -0400
From: jmk@plan9.bell-labs.com jmk@plan9.bell-labs.com
Subject: Licensing plan9 on MP machines
Topicbox-Message-UUID: 509c3774-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19961026034207.F249uNpjDIKqwu0x-PkNhhkPT3fGH8cDY87NSbwgH88@z>

	I am looking into the possibility of porting plan9 to an MP
	machine and am wondering what the licensing issues are for
	parallel machines.  Do they count as a single machine or
	does each CPU require a license?

It counts as a single machine.

	According to the FAQ, Brazil supports dual-processor Pentiums
	where does Pentium Pro (P6) support stand?  The machine in
	question is a hybrid SMP-MP design -- each node is a two-way
	P6 with shared memory, but the nodes are connected via
	a message passing mesh.

The x86 multiprocessor code runs on Pentium or Pentium Pro systems which
conform to the Intel Multiprocessor Specification, there were no changes
required for the Pentium Pro. There's about 1000 lines of code, most of it
is concerned with parsing the configuration table created by the BIOS. A
small number of changes were made to the base x86 code - some mmu data
structures were made per-processor and some locks were added to some device
drivers where uniprocessor operation had been assumed. The only change
in the port code was changing 6 references of 'm->' to 'MACHP(m->machno)->'
in proc.c as the nature of the x86 mmu required 'm' to be a fixed virtual
address.