Interleaving VAX 780 memory

[aps at decvax.UUCP]

Steve Kramer:
The code for interleaving memory on the 780 is not in UNIX at all but is
in the console boot floppies in the command files (all the boots and restar).
This is not a permanent change.  There are bits in the registers of the
memory controllers that you twiddle.

Here is our defboo.cmd:
	! BOOTSTRAP BY BOOT() SYSCALL
	! GO MULTI-USER AFTER CHECKING; BOOT FROM DEFAULT DEVICE
	!
	SET DEF HEX
	SET DEF LONG
	SET REL:0
	HALT
	UNJAM
	INIT
	D/P 20002000 101
	D + 4000
	D/P 20004000 101
	D + 4000
	LOAD BOOT
	D/G B 0		! BOOT PARAMETERS: MULTI USER AFTER CHECK
	D/G A 0		! DEV TO BOOT FROM (0=HP, 2=UP, 3=HK)
	START 2

The deposits of the 101(16) are to configuration register A and are the
interleave bits write enable and the interleave bit.  The deposit of 
4000(16) is to config reg B and is the enable write to starting address
bit and the starting address of 0 (which should be the same for both
controllers).
Note that the addresses are for our configuration and although they
are pretty standard, could change.

In order to boot in a non-interleaved configuration, just use a
different boot file.
	aps.