10 Sep
2007
10 Sep
'07
12:22 p.m.
Subject: Re: Portable PDP-11 (was Re: Does anyone use RT-11?)
From: "Ethan Dicks" <ethan.dicks at gmail.com>
Date: Mon, 10 Sep 2007 13:55:56 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On 9/10/07, Allison <ajp166 at bellatlantic.net> wrote:
Very handy.
Required! ;)
"Ethan Dicks" <ethan.dicks at gmail.com wrote:
On 9/9/07, Allison <ajp166 at bellatlantic.net> wrote:
I have a lot on paper plus the ever important T-11 manual. One day I plan to get a T11 up and running wtih
RT but with non-DEC
drivers for terminal and storage as a small toteable -11.
I'd like to hear more about this... However
it has stopped at that phase mostly due to other projects having
my interest.
Fair enough. I think most of us have a variety of projects cluttering
our foreground task.
... only 8KW ram, 8KW Eprom and a DLART for
serial IO.
Certainly minimal, though today, 28KW of RAM isn't a stretch. The display is
really the harder part at least for portability and power
consumption. However for this one I was considering packaging along
the lines of the Kaypro totables and wall power. Part of this recognizes
the T-11 uses a fair amount of power (Z80 NMOS is similar) and most of
the parts around it will not be CMOS so battery operation is not easily
accomplished.
Understandable.
As for
storage, obviously some flavor of FLASH is great for most
things...
None of the above for cost or availability reasons. I'd opt for IDE
using one of the many 40-500mb drives I have. While
textual LCDs are cheaper and easier to interface to, the largest
one I've seen is 4x40. A graphical LCD panel with a SED1335 or t6963
of a size of 640x200 would be perfect for 80x25...
I planned on text. However it's possible to get LCDs used for laptops
but the logic to drive them is non trivial. Back to the T-11, though, if I recall its capabilities
correctly, it
doesn't have an MMU, and it would be difficult, if not impractical, to
design an external one that resembles, say, the MMU on an 11/23...
Correct on the OS and software. However the MMU is very buildable
and not near as hardware intensive as would seem. For an example
look at the T-11 interface in the VT240. It takes a few 16x4
bipolar rams and some loose logic to implement the paging (2 74189,
3 74ls257 and a bit of TTL glue) to make a a compatable (mostly) mapper. I even happen to have a small pad of 74189s.
Same here.
One of the things I've given consideration to
in recent years is a nonDEC
and non *nix OS such as CUBIX as that would translate reasonably from
6908 to PDP-11. This arises from the fact that RT-11 has a very
primitive filesystem compared to CP/M and an OS that is not encumbered
would be easier to work with.
Hmm... from what I've seen of CUBIX, it sounds feasible for a PDP-11
host, and it certainly gets around the issue of what OS to distribute,
but I would think that porting CUBIX could be an entirely independent
project (focusing on whatever display and mass-storage interfaces are
available). So, Allison, does any of this sound like what you had
in mind... ?
You envision what sould like a Laptop. I can't easily fabricate that
but a toteable like Kaypro, Osborne and a few others is very doable. The basic
machine description is a 128kW using 32kx8 static parts (8pcs),
Boot roms/ODT, MMU, two serial, parallel (PC conpatable for printer)
and IDE disk. Things like OS in Eprom have surfaced to my idea pool
to consider especially if it were not RT11 (CUBIX influence). Terminal
logic would be VK170 (base VT52 on a dual size card) and a monitor in
the 7-9" size.
OK. I'm not sure I get the "VK170" reference. Is that some sort of
DEC or 3rd party embedded product? Thanks for sharing your design ideas.
They aren't patented. ;)
Allison