booting from RQDX3

From: Pete Turnbull <>
Date: Fri Jun 1 14:47:47 2001

On Jun 1, 14:45, Jonathan Engdahl wrote:
> Putting a ROM on the disk controller at 173000 is the usual way
> of doing it, but here's a slick alternative that is used on the
> DSD 4140 floppy controller:
> There is no ROM onboard other than the microcode for the AMD
> 2901 (one 4-bit slice!), but there is a single register mapped
> onto the Qbus at 173000. If the PDP-11 jumps there, the
> controller gives back a jump-to-self opcode.

I've seen (indeed, own) another card that does that. I think it might be
one of my Dilog cards, but it could be the GR RXV21.

Pete						Peter Turnbull
						Network Manager
						University of York
Received on Fri Jun 01 2001 - 14:47:47 BST

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