12 Jun
2000
12 Jun
'00
10:26 a.m.
The DECmate II and (I presume, although I've not
played with one) the III
use Harris I/O support chips. The first thing you need to do to these
chips after power-on is to configure their address. Consequently, there's
a table of IOTs executed by the processor straight out of reset to get
the job done. It should be possible to switch the addresses configured
True.
for the console port and the printer port in that
table. The effect would
be that the printer port would now be the console port and the terminal
emulation in the slushware would now run the printer port.
Will not work.
No, I've not tried this. Furthermore, every time I
mention the possibility
some pretty knowledgeable folks usually tell me it won't work. I don't
see why it won't work.
Simple, the slushware does the port to 5027based video and keycodes to
ascii translations and terminal emulation. You would not want that
inbetween a nominal serial port and the system while using a terminal.
To do thiswould require modding the slushware so that a normal console
requests are mapped to another port. the problem is that the 03/04 ports
do not support the full set of standard IOTs for TTY and interrupts.
the rest of the ports are even less like standard PDP-8 IO so you would
at a minimum be designing a full set of slushware and IOTs.
That is the crux of the Lasner ravings as to why a DECmate is not a PDP-8.
It is a system that is largely pdp-8 in character because of a micro that
executes most PDP-8 opcodes. However there is a holw class of PDP-8
things a decmate can't due to lack of buss access and the ability to
interface to real PDP-8 peripherals (not easy to do threy cycle databreak
using the CMOS CPU as a coopertive element).
check UU.SE and also www.dbit.com the nickles directory.
Allison