>From: "Joe R." <rigdonj(a)cfl.rr.com>
>
> Does anyone know anything about Zitel? Pr what bus this card uses or
>anything about the card? <http://www.classiccmp.org/hp/a4/zitel.jpg>. I
>seem to remember that Zitel was a copy cat of Intel.
>
> Joe
It looks like 2 banks of 16 bit RAM with parity. As a RAM
board, it shouldn't be too hard to trace out the address
selects.
What size RAMs are they?
Dwight
>From: "Norm and Beth Anheier" <anheier(a)owt.com>
>
>Anyone have an Intel C4040 processor that they would be interested in
>trade or selling???
>
>Thanks Norm
>
>
Hi
I don't think I ever saw a ceramic 4040?
Dwight
On Dec 13 2004, 6:21, Steve Thatcher wrote:
> the one floppy deal is not really a bios issue, it is a hardware
> issue. As long as there are two drive select lines coming from the
> hardware, then the mb can supprt two drives even if there is not bios
> support. My ASUS P4 mb only supports one drive and I suspect that
> there is only one drive select. Bios code is meant to support the
> hardware that is present. At least that is the way is has been for 23
> years...
That's like mine. The motherboard only has one drive select line, so
the BIOS normally shows only one entry for a floppy. However, if I
disable the on-board FDC and add a normal FDC card, I can use two
floppies and the BIOS detects and shows settings for both.
--
Pete Peter Turnbull
Network Manager
University of York
Any of the CGA monitors I have at home have a captive cable with, IIRC, a
female DB9.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org]On Behalf Of Eric Smith
Sent: Tuesday, December 14, 2004 4:39 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Off the wall CGA monitor question
Scarletdown wrote:
> All of the CGA cards that I can recall seeing had female connectors, so
> most likely, the monitors have male connectors.
That only implies that the *cable* has a male connector on one end; it
doesn't really tell you anything about the monitor.
I'd be inclined to expect that most CGI monitors either had a captive
cable, or had a female connector on the monitor as well. But it's been
so long since I looked at CGI monitors that I don't recall.
Eric
Pulled out the drawer in the expansion chassis on our PDP-11/70 and then
attempted to squat down behind it. Since I have such great balance I
fell forward and leaned into/onto the PDP-11/70 backplane and punctured
my palm many times with the nice little wire wrap pins. Interesting
pattern, very little blood, I thought of a tattoo.
Pins are nicely tipped with pyramid suitable for puncturing skin. No
worry in those days about any infections since I was young an
invincible.
Maybe a slight variation on an old adage: Blood, sweat and tears must be
shed for the computer to compute correctly.
Mike
Tore S Bekkedal <toresbe(a)ifi.uio.no> wrote:
> Norwegian trains run DC...
As do Russian electric trains. 4 kV.
> I've seen a tagger actually climb up on the
> roof of a train, and before I could run to the veranda of my appartment
> to tell him to get the fuck down, the dumb fuck stood up. He illuminated
> the entire train exchange for a millisecond, and then all that was left
> of him was one of his feet, that apparently hadn't made contact with the
> grounded train roof. His charred remains were still burning 20 minutes
> later, until the firemen came and cleaned up the mess.
Ouch. My dad told me a story of something similar happening in Russia
with an unlucky railroad maintenance worker. Apparently the vertical
spacing between the roof of a train car and the high voltage wire is high
enough for workers to be able to walk on the roof under the wire and not
touch it, even though it doesn't seem that high when looking from the
ground. But that unlucky worker was carrying a wrench in his hand and
had it stuck up in the air...
When I was an intern on the Moscow railroad I witnessed another incident,
this one fortunately without fatalities or human injuries, but demonstrating
the power of that DC supply. On Russian and probably many other railroads
the rails carry both the power current (return) and signaling current.
The power current is DC, the signaling current is AC (at very low voltage
of course, 6V). The track is divided into block-sections, each block-section
monitored as a unit and reported as free or occupied to the rail traffic
control system. Block-sections are separated by insulated rail joints.
Each end of a thus isolated block-section is connected to a transformer
whose other (higher voltage) winding is connected to a wire pair going back
to the rail traffic control centre. Simple enough on diesel-powered railroads.
It was a little more complicated on electrically powered railroads. The
thick copper wires from the ends of each insulated joint were connected
to transformer windings like before, with a separate transformer for each
side of the insulated joint. The high-voltage windings were connected to
signaling lines like before. But the low-voltage windings, the ones connected
to the rails, were centre-tapped, and the centre tap from the transformer
on one side of the insulated joint was connected with a thick copper wire
to the centre tap on the other side. This way the DC power current effectively
passes right through while the insulated joint acts as a barrier to the
signaling AC current.
The town where I lived and the railroad station on which I had my internship
was on the end of a low-traffic branch of Moscow railroad. The station
itself had electric centralisation, the term used in the Russian railroad
technical documentation for the rail traffic control system at a station.
The track stage between that station and the next, however, was unmonitored.
What this means is that at the station the left and right rails had the low
signaling AC voltage between them, but out on the stage the two rails were
simply connected. Thus the last insulated joint at the station boundary
had only one transformer box next to it, the ends of the winding connected
to one side and the centre tap connected to the other side.
Well, one fine day a track maintenance vehicle knocked that transformer
box down, and it fell tumbling down into the ditch. Apparently the track
maintenance workers didn't notice it and went on with their business.
But the monitoring circuit was broken of course. Rail circuits are normally
closed. An open rail circuit corresponds to a track section that is either
busy (the train axles short the circuit and all the current goes through
them rather than through the relay on the other end, so it reports as open)
or broken (a rail broke under load or was removed by terrorists, etc).
So when that transformer box got knocked down and the circuit broke, it
just lit a red light on the panel in the rail traffic control room
indicating a busy track section. We (the traffic controller lady and
me-the-intern) noticed it and went to check it out, but the trains still
had to go on schedule while a crew was dispatched to mount the transformer
box back where it belongs. So we let one or two trains through, using
the manual override button to override the track busy status. (The manual
override buttons have seals on them that you have to break in cases like
this when you have to use them, and LOTS of paperwork must be generated.)
So we let those trains through. Now think what happened when the train
crossed that insulated joint and continued on our side, our station being
the end of the line. From what I understood when I was there, our end
was not the one supplying train power, so when a train was on our side,
its return current had to go through that insulated joint, i.e., through
the transformer centre tap. With the transformer gone, where did the
current go? Well, it arced right through the insulated joint and melted
the ends of the rails. Pretty impressive.
MS
> I've been working on creating a clone of DEC's maintenance panel
> (KM11)
> for some time now. I intended it to be used as my "hello world" board
> to get familiar with EagleCAD and the board fab process.
>
> On Friday my first boards arrived from the fab house. I spent this
> weekend building up 2 boards and both worked perfectly the first time.
> It was so cool to be able to single step the microcode in an 11/40!
>
> It's up on my web site
> (http://www.shiresoft.com/pdp-11/boards/index.html) for those that
> want
> to see what it looks like. Sometime this week I'll take a picture of
> the 11/40 with 2 KM11's hanging out of it!
>
> My first batch of boards/parts has already been spoken for. But for
> any
> who are interested, I'll place another order for parts/boards for
> delivery sometime in January.
>
> Each board will come with complete schematics, parts list and assembly
> instructions. I will also have collected drawings for the overlays
> and
> instructions on use for the various processors (11/20, 11/05, 11/40,
> 11/45 and 11/70).
>
> I'm pricing as follows:
> "Bare" Board $75
> "kit" (includes all the parts) $125
> assembled and tested $250 (I really don't want to)
>
OK, I just got a couple of board quotes with larger quantities. If I
can get an order of ~50 boards, I can drop the prices by $40! So the
pricing would be:
"Bare" Board $35
"kit" (includes all the parts) $85
assembled and tested $250 (I still don't want to)
If I can get a preliminary count of folks who want one (or two or ...) I
can get the boards and parts ordered. I'd like to place the orders
during the first week of January.
--
TTFN - Guy
