I've recently been in the midst of repairing an EAE set for the Omnibus. I
finally got it working tonight. Surprisingly, unless I was simply reading
it wrong, it appears as though the M8340 etch rev. D is in fact compatible
with M8341 etch rev. D, despite what the DEC ECO Log suggests. Now, on the
other hand, the M8340 does have some ECO changes, but some of these are not
cited in the log, perhaps indicating that it was brought up to an
equivalent revision E or F, but there are still some big differences
particularly involving the inputs to the instruction register.
Anyways, here's an album: http://imgur.com/a/QVRLs
The TL;DR of it all is I replaced one bad IC. I also ended up making a
board that replaces the hard-to-find Signetics N8235 with easy-to-find
7400-series components.
A big thanks to all those involved (you know who you are!) in helping get
this set functional again, just in time for VCF East and Southeast!
Kyle
This is a classic case of "Great minds run in the same ruts" (sometimes
rephrased as gutters...)
I've almost designed a 4 MB card twice now. Because I'm a cheapskate, I
didn't want to use FRAM. And there are very nice SRAMs available: for
example, the Cypress CY62167 is a 2Mx8 1Mx16 RAM in 48 pin TSOP. So you'd
need two, that's ~$30 total. (n.b. there is a 4Mx8 but it's only in BGA, so
fuggitaboutit).
So, you'd only need the bus interface (no, I'm not going there) and the
control logic.
These SRAM parts are so speedy (45 ns) that cache isn't needed (obviously).
Maybe I'll almost design it for the third time!
Jay.. think of the children! ..and wives...and other non octal folk and how long it will take to explain the shirt! ;-)
<div>-------- Original message --------</div><div>From: Jay West <jwest at classiccmp.org> </div><div>Date:03/17/2015 1:33 PM (GMT-06:00) </div><div>To: "'General Discussion: On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org> </div><div>Subject: RE: VCFMW 10 Hotel Rooms </div><div>
</div>
...Defcon alread did the hexidecimal thing with their 10th being "0A."
012 because Octal is where it's at ;)
On 18 March 2015 at 19:18, tony duell <ard at p850ug1.demon.co.uk> wrote:
> Not part of the _video_ signal, but part of the overall signal : IIRC continental Europe (mostly?) put the sound
> carrier 5.5 MHz way from the video carrier, but the UK had a 6MHz offset.
>
> -tony
SECAM comes in two variants, one with a 5.5MHz sound carrier offset
and another with a 6.5MHz offset. The Russians apparently use a
variant of the latter - many years ago I visited a family living close
to the Russian border and they used to tune in to Russian TV on their
black&white TV. But they had a hard time getting picture and sound at
the same time, IIRC it was either one or the other. They would tune to
sound or video depending on what was on - there are some great
classical music programmes so presumably that's when they tuned to
sound only.
As for NTSC - 'never twice same color' - that sounds cumbersome, what
we learned in (TV repair!) school was 'Never The Same Colour' :-)
(PAL means Phase Alternating Line, except for the lines/frequency
differences it is really just NTSC but with the phase of the colour
subcarrier alternating every other line. Thus automatically cancelling
out transmission phase errors which would otherwise change the colour.
That's all really: NTSC with automatic colour phase error
cancellation.)
-Tor
BASIC Week 4 starts on RetroBattlestations on Saturday, March 21st. The program this time around is a Space War inspired turn based game with simple graphics, so it doesn't need a fast computer.
This will be the 4th BASIC Week we've done on RetroBattlestations, the previous two used ASCII graphics, and the first one used simple vector graphics. The challenge is about getting out old computers and doing something with them, in the spirit of the old type-in magazine listings. Usually there a lot of ports to various platforms, although the past programs have been a lot smaller. This will be the largest one yet and might be almost too big to actually type in. While the contest is more about having fun with your old computers, there are prizes. At the end of the week I randomly select five winners and send them their choice of two retro themed vinyl stickers:
http://imgur.com/a/iAS5T
So far the only versions of the program are for an Apple II and the original HP 3000 which used terminal graphics. If anyone would like to contribute a another port, that would be awesome! The program is on github, you can find the link here:
http://redd.it/2yi2d2
--
Follow me on twitter: @FozzTexx
Check out my blog: http://insentricity.com
I recovered a bunch of old floppies for a friend of mine. Her documents are
>from the 1980s, but all in LEWP format. Alas, I could not recover the disk
with the binary on it. :-(.
I am hoping someone has a copy of the binary or a pointer to the file
format so I can write my own converter. I can't find either
On Tue, Mar 17, 2015 at 4:22 PM, Pontus Pihlgren <pontus at update.uu.se>
wrote:
> On Tue, Mar 17, 2015 at 04:08:26PM -0400, Ethan Dicks wrote:
> >
> >... How many 11/70s are in the hands of folks like us?
>
> Quite a few I would think. We have no less then three at the club. And
> of the top of my head there are at least three more owners on this list.
>
> Given how many of the more rare machines people have, I'd venture that
> there are at least 25, if not more, 11/70 machines in private hands.
>
> /P
>
So, I've never thought of the 11/70 as being "that rare", but "at least 25"
still sounds to me as being fairly uncommon as PDP-11's go?
How (relatively) common are the remaining early 11's these days? With some
lumping, and ignoring the F11/J11-based ones, in these categories: 20/15;
10/05; 40/35; 45; 50; 55; 60; 70; 34/04; 44? The last two I'm thinking are
still quite common; really no idea about the others ... although the number
of remaining 11/60's seems to be in the bare-handful category. 50's and
55's might be similarly low?
-----
paul
> From: Paul Koning
> if the CPU generates an address in the range 17000000 to 17577777, it
> lands on the Unibus and is then mapped by the Unibus map.
Umm, I think you meant "to 17 757 777", no? (Too many 7's - I find it helpful
to break them up into groups of 3, the way DEC does, to prevent that kind of
confustion.)
> More precisely, it works that way for 11/44 and 11/70 - but not for the
> J-11. That's a difference not documented in the PDP-11 Architecture
> handbook model differences table
But, but, but... the J-11 doesn't _have_ a UNIBUS map! Well, the 11/84 and
11/94 do, but not other J-11 machines. (And the Architecture Handbook table
does not have separate columns for the 11/73, 11/84, etc.) So an 11/73 can't
have a reference in the range 17 000 000 to 17 757 777 go out the UNIBUS -
there isn't one! :-)
So what happens if one does a reference to something in the range 17 000 000
to 17 757 777 on the 11/84? The 11/84 _does_ support having memory on the
UNIBUS (up to 248KB), _but_ how it appears depends on how much there is. (See
section 3.13.2, EK-1184-TM-PR2.) There's a special register to configure it
(the 'KTJ11-B Memory Configuration Register', KMCR), which includes _how
much_ UNIBUS memory there is.
If there is _no_ UNIBUS memory, then PMI memory appears (to the CPU) at 0 up,
and the UNIBUS Map is enabled. References to 17 000 000 to 17 757 777 go to
PMI memory ("PMI memory, as seen by the CPU, resides in contiguous locations
>from 0 up to as high as 17 757 777"), and presumably if there is no PMI
memory there, they fail, they don't even go out the UNIBUS to see if anyone's
home.
If there is _no_ PMI memory, then _UNIBUS_ memory appears (to the CPU) at 0
up, and the UNIBUS Map is _disabled_. (And I assume references to the range
01 000 000 to 17 757 777 just immediately fail.)
If, on the other hand, there is a _mix_ of PMI and UNIBUS memory, things get
really wierd. UNIBUS memory does not appear at 0, _or_ at 17 000 000 up to 17
577 777; instead, that memory appears to the CPU (depending on how much there
is) from 17 757 777 _downwards_ to (17 600 000-UNIBUS_memory_size); UNIBUS
memory apparently has to be assigned UNIBUS addresses from 757 777 _down_
("[UNIBUS] DMA Address XXX XXX accesses the same UNIBUS Memory location
accessed by CPU addresses 17 XXX XXX").
(Which is slightly odd because in the case where there is no PMI memory, the
UNIBUS memory needs to be assigned UNIBUS addresses from 0 up, which is quite
different from how to assign UNIBUS addresses to that memory in the 'mixed'
case. But never mind... :-)
The UNIBUS map will not respond to UNIBUS cycles in the address range
assigned to the UNIBUS memory.
And, to look at the original point, I would _guess_ that references to
locations in the range 17 000 000 to 17 757 777, but below the configured
UNIBUS memory, again don't go out the UNIBUS, but try and perform a PMI
cycle, which may or may not fail.
Basically, it seems like DEC was determined not to waste any address space on
the J-11/UNIBUS machines. Either it's configured as UNIBUS memory, or it's
PMI.
The KTJ11-B can also be configured to operate in 18-bit mode, with a mix of
PMI and UNIBUS memory, but I will leave the ugly details unless someone is
particularly interested in them! :-)
Noel
> From: Michael Holley
> The French standard is SECAM, which stands for "System Essentially
> Contrary to American Method"
The French! Don't get me started on the French!
(If there any French people on here, don't worry, you're all forgiven, because
of CYCLADES! For everyone who doesn't know what CYCLADES is: Google it!! These
bits are coming to you via its descendant! :-)
Question: Why is the ATM cell payload 48 bytes?
Clue #1: Multiply 1/c by the largest diameter of France.
Clue #2: What is a camel?
Noel
