Does anyone know who does this site:
I looked, and didn't see anything in the site itself, and doing a 'whois'
didn't turn up anything useful.
The site has some really nice PDP-5 photos which I was wondering if that
person could/would put in the public domain, so I can use them for a PDP-5
article I'm working on for Wikipedia and the CHWiki. So I'd like to get in
contact with them.
On Sat, Oct 28, 2017 at 1:42 PM, Paul Birkel <pbirkel at gmail.com> wrote:
> Are you sure that you're not looking at a local cache?
It doesn't look like a local cache to me:
tingo at kg-core1$ curl http://pdp8.org/ | head
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:--
--:--:-- 0<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01
<meta name="POSTINFO" content="http://www.pdp-8.org/postinfo.txt">
<meta name="ProgId" content="FrontPage.Editor.Document">
<meta name="keywords" content="pdp8, pdp12, pdp-8, pdp-12, linc">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<title>PDP-8.org: a PDP-8 and PDP-12 resource</title>
100 8656 100 8656 0 0 8656 0 0:00:01 --:--:-- 0:00:01 30265
curl: (23) Failed writing body (0 != 1603)
tingo at kg-core1$ host pdp8.orgpdp8.org has address 18.104.22.168
pdp8.org mail is handled by 10 mx.spiritone.com.
tingo at kg-core1$ ping pdp8.org
PING pdp8.org (22.214.171.124): 56 data bytes
64 bytes from 126.96.36.199: icmp_seq=0 ttl=55 time=139.792 ms
64 bytes from 188.8.131.52: icmp_seq=1 ttl=55 time=140.435 ms
--- pdp8.org ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 139.792/140.113/140.435/0.322 ms
On 10/27/2017 01:01 PM, Paul Koning wrote:
> Oh yes, and if you look at the wire lists (on Bitsavers) you will get the length of every wire in the machine. The trouble is that, even if you use the documented delay per foot, things don't necessarily match. The stated logic stage delay is 5 ns, no special numbers given for twisted pair drivers. In my model, I do everything in 5 ns multiples (to keep the simulation time under control). That works pretty closely, but not 100 percent, not for some of the CPU pieces. The other thing that's nuts is that the CPU effectively has a 20-phase clock: the documentation shows clock signals with offsets from the reference time given in multiples of 5 nanoseconds (for the 100 ns clock period). And yes, it matters. And yes, many (I'm not sure about all) of the 20 phases are actually used in the CPU.
I can't recall, but didn't the 6600 have something like 10 clock
sources, all kept synchronized?
In any case, it's a gross oversimplification to say that the 6600 had a
10 MHz clock.
I have an Apple II that produces one beep at power on, but my monitor says
"no video present". A scope on the output shows frame sync but at low
levels. The odd thing is that ic A9 appears to be a 74S151 not a 74LS151. I
wouldn't expect this to work, but I assume it was working at some point in
I have done some googling and can't see any reference to this substitution.
Is it something any one else has seen?
> From: "Rob Jarratt"
> I misread your email as suggesting that the 124 was more suitable than
> the 122
No, it's just cheaper (at the moment), and can be made to work.
> My H960 is not very accessible but I attempted to measure it front back
> and it may be 25". Do you know where should the length be measured?
You don't need to measure anything. The C-230-S-122 is the _exact_ part DEC
used originally for mounting RK05's in H960's.
I've been trying to unsubscribe from the list. I did it once before and
hadn't seen anything for months. However, I suddenly started receiving
mails last weekend. I went to the webpage to unsubscribe but I can't login
and neither the password reset or unsubscribe confirmation make it to me.
So I'm hoping someone can tell me how to contact the list admin. I emailed
an address I found on the website but I hadn't received a response yet. I
may not have waited long enough but I don't know.
> From: Kip Koon
> I tend to get emulation and simulation a bit confused.
You and me both!
I think part of the problem is that there is no generally-agreed-upon
definition of the two terms.
I like this one a lot, though:
Emulation is the process of mimicking the outwardly observable behavior to
match an existing target. The internal state of the emulation mechanism
does not have to accurately reflect the internal state of the target which
it is emulating.
Simulation, on the other hand, involves modeling the underlying state of
the target. The end result of a good simulation is that the simulation
model will emulate the target which it is simulating.
Ideally, you should be able to look into the simulation and observe
properties that you would also see if you looked into the original target.
In practice, there may some shortcuts to the simulation for performance
reasons -- that is, some internal aspects of the simulation may actually be
EDIT: Other responses have pointed out that the goal of an emulation is to
able to substitute for the object it is emulating. That's an important
point. A simulation's focus is more on the modelling of the internal state
of the target - and the simulation does not necessarily lead to emulation.
... SPICE, for example, cannot substitue for an actual electronics circuit
There's also the question of what's being emulated.
Ersatz-11, for example, does a good job of looking like a PDP-11 - for the
software. However, it does not like a PDP-11 for the hardware (although John
used to sell boards you could plug into a PC, which provided a QBUS, IIRC).
So is it a simulator or an emulator? Good question.
About the only _generally-agreed_ example of the terminology I can think of
are 'in-circuit emulators', which _exactly_ match the behaviour of a given