Booting from memory

[John Klos <john%ziaspace.com@localhost>]

Hello, VAX people,

Last summer I wrote about issues I am having with my VAXstation 4000/90a: 
http://mail-index.netbsd.org/port-vax/2015/08/22/msg002580.html

I had a little time recently so I wrote a quick script which takes the 
converted hex of the MOP bootable COUGAR.SYS utility for updating the 
FEPROM and outputs it on a "d/L+" line starting at memory address 1000000 
with a tenth of a second delay between each line. So far, so good, but 
it's going to take around four or five hours to send 512 megabytes this 
way.

However, before I run anything which may possibly make things worse, I'd 
like to test to see if this would work.

What's the usual address to which MOP loads on a 4000/90? Should I use 
that as the load address?

IIRC, I'd start 512 (0x200) bytes in to the MOP image, or 1000200, 
correct?

A quick test trying to boot MOPBOOT.SYS from memory this way didn't work:

> > > unjam


> > > start 1000200

?0A CHM FR ISTK
  PC= 01000234 PSL= 041F0004

Ideas?

Thanks,
John