On Fri, 21 Oct 2005, Allison <ajp166 at bellatlantic.net> wrote:
> >Subject: Re: RL01 drive select plug and power supply questions
> > From: Paul Koning <pkoning at equallogic.com>
> > Date: Fri, 21 Oct 2005 10:58:55 -0400
> > To: cctalk at classiccmp.org
> >
> > Allison> Yes I do. However for a single user system the load is not
> > Allison> an issue. If your running a timeshare system such as RSTS
> > Allison> or RSX with more than one user then DHV11 sense as well.
> >
> >Not true. 9600 baud is 960 interrupts per second, on a character I/O
> >device. That's a big number for a PDP-11. Output will be
> >significantly less of a burden with a DH type output controller than
> >with other types -- even for just one active terminal.
>
> Depends somewhat on the OS. It dont know about you but most people
> can't type much faster than 100WPM (less than 10 chars sec).
Um, that's irrelevant. A DH type controller also interrupt on each
character input. It's output that differs. And filling a full screen is
1920 characters, which at 9600 bps will take about 2 seconds. Do that on
one terminal will the system will definitely notice. If you have a serial
printer of some speed (such as an LN03) we're talking about a lot more
than about 2k of data sometimes. So even with a single user system, it can
make a big impact. And of course, if you have anything else running at the
same time, it will make it even worse. Multi-user systems definitely
suffer if you use DL11 controllers for users. It's more or less a no-no.
I'm not even sure you can drive one single line at 9600 bps at full speed
on a DL11, let alone 19200.
> For RT11 it's mostly unimportant. For unix (the most sensitive
> to interrupt loading you _may_ care as a single user).
It matters for both, as I've pointed out above.
> > Allison> For most of my 11s four lines is the limit for what I can
> > Allison> seem to keep busy. Figure a user terminal, LA100 Printer
> > Allison> and serial line for modem or data line to another system. At
> > Allison> the extreme I've run two terminals for OSs that support that
> > Allison> but, I can only type on on at any instant. ;)
> >
> >Sure, if you're mostly doing editing, then the CPU burden of high
> >speed output may not be obvious. If you had an LN03 or similar
> >printer, you might see it more easily. An LA100, of course, isn't
> >much of a problem because it is quite slow.
>
> Actually printers are a bursty load (fill the buffer and go away)
> and I've found that in practice the faster you fill the buffer
> the better (high line rates or use a parallel interface).
Yes, and that burst will drop a PDP-11 to it's knees if it's on a DL11 at
high speed. Sure, if you're running 2400 bps then you'll live. But not
many does these days.
> Performance was good enough that we used that over the VAX
> (line lengths limited us to 2400baud in our part of the mill).
Yes, interrupt performance on the VAX was not pretty. One or two DZ11 on a
VAX-11/750 would kill it.
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Fri, 21 Oct 2005, Allison <ajp166 at bellatlantic.net> wrote:
> >Subject: Re: Wondering which OS to use (PDP-8/A)
> > From: Johnny Billquist <bqt at Update.UU.SE>
> > Date: Fri, 21 Oct 2005 13:06:20 +0200 (CEST)
> > To: cctalk at classiccmp.org
> >
> >On Thu, 20 Oct 2005, Ethan Dicks <ethan.dicks at gmail.com> wrote:
> >
> >> You may or may not have an RL boot PROM in your KM8AA, but if you
> >> don't, you can always key in the RL bootstrap by hand.
> >
> >I'm not even sure they exist. Anyone have boot roms for RL?
>
> There must be as DEC sold 8As and RL02s as multi user WPS systems
> (wps200 comes to mind).
Good point!
> No idea what the underlying OS for WPS was.
There wasn't any. WPS is self contained. I have a RX01 floppy with WPS-8
somewhere... I've even booted it on one 8/A here. Works fine. :-)
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
On Fri, 21 Oct 2005, Johnny Billquist <bqt at Update.UU.SE> wrote:
> However, it won't be much for the original question on this thread, as
> Multos don't support the RL8A either...
I'll correct myself. Multos does support the RL8A, as I discovered when I
checked the sources after I posted. However, they appear to only have used
RL01s. So I don't know how it will behave with an RL02.
(When I played with it last, I only used RK05).
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
Turns out the second bit wasn't a varistor, but a disk cap (.1mfd/50v)
I'm now trying to figure out what happened. It seems rational that the paper cap blew first, but from there I'm not sure. It seems a bit bizarre that two caps blew at the same time.
The paper cap was wired between the primary of a transformer and a large power resistor that connected to (ground? the other side of the primary, anyway, and whatever that went to). The second problem area was from the secondary of the same transformer. 4 leads run to a stud rectifier bridge, and across each stud there is a .1mfd/50v disk cap dumping into a 3.3ohm 2-watt resistor connected to the other side of the rectifier. This resistor burnt up.
The only options I could think of was that the demise of the primary cap set up a oscillation of sufficiently high frequency that the reactance of the .1mfd cap was sufficiently low that enough current went through to overload the resistor, or (2) 2 capacitors went on the fritz, and on the second one the shorting whiskers burnt away without blowing the cap because of the load resistor, which smoked instead, or (c) some bizarre transient appeared on that winding that blew the 50v dielectric and was blocked by the final output choke so that it didn't blow the final 7.5v electrolytic filter caps.
And now for the question- I have new caps/resistor- should I look anywhere else for problems before I plug everything back together? None of my theories sound really convincing, and I don't want to blow anything else in this machine.
At 12:00 -0500 10/21/05, Roger wrote:
>What would $550 *actually get you*??? Perspiring minds wanna know!
I assume it *very very cleanly* conducts the noise from your power
outlet to your amplifier.
Ya know the face I'd like to see?
Take somebody that just bought one of those cables outside his house,
point up at the power line coming to his house, then whip out an AM
portable, scan down the spectrum, and let him know that *all of that*
was hitting his socket, and being transmitted with extreme fidelity
across his $550 power cable to his power supply.
That's the face I'd like to see.
--
- Mark
210-522-6025, temporary cell 240-375-2995
>
>Subject: Re: Character Generator ROM data
> From: cswiger <cswiger at widomaker.com>
> Date: Fri, 21 Oct 2005 22:40:35 -0400 (EDT)
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On Fri, 21 Oct 2005, Allison wrote:
>
>> >
>> > From: Chuck Swiger <cswiger at widomaker.com>
>> >I'm looking for a downloadable rom image for something like in old video
>>
>> Is simple. Find a pattern you like in row or colum scan and convert the
>> bit pattern to a string of hex values and cook an Eprom/EEPROM.
>>
>
>Ok - Just probing for any existing rom dump files that might be out
>there w/o having to type a bunch of stuff in ;)) I've an opportunity
>to put a message in an unusual place.
>
>--Chuck
Dont have any on line myself. However I've done it by hand and it's
not bad. Actually you can do a cleaner set without all the fluff
or with needed chars. One thing, the Eprom or EEprom needs to be
adaquately fast. Not a big problen with moderm parts but the old
2716 and 2732 were a tad slow.
The search string was a first try thing. So you may start with that
and tweek if for what you want. I'd be surprized if there isn't something
out there.
Allison
Chuck,
Did a quick Google on "character generator roms" and this was the third hit.
http://www.atariarchives.org/cgp/Ch02_Sec04.php
Hope it helps.
Allison
>
>Subject: Character Generator ROM data
> From: Chuck Swiger <cswiger at widomaker.com>
> Date: Fri, 21 Oct 2005 21:47:44 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>Gang -
>
> Anybody know of readily available data for, say, 7x9 dot-matrix characters?
>I'm looking for a downloadable rom image for something like in old video
>cards to
>paint ascii characters on a display.
>
>For example, my Polymorphic Systems Video Terminal Interface (VTI) card uses
>an MCM6571A (or it could use a 6574) -BUT- I do not need exactly that
>font - any 7x9 data will work. Spent the past hour trying terms in
>google w/o
>anything usable turning up.
>
>
>******* ***** *
> * * * *
> * * * *
> * * ******
> * * * *
> * * * *
> * * * *
> * * * *
> * ***** * *
>
>--Chuck
Today I hit the wrong recessed button (of two) on my pdaphone.... goodbye
all phone numbers, email addresses, etc.
My business contacts are easy to replace, but my classiccmp info isn't :\
Many of you here I had home phone numbers and/or cellphone numbers, etc. Not
anymore.
So, if you are sorry you ever gave me your number(s), just ignore this
email. Otherwise, email me your contact info OFFLIST please. This isn't a
solicitation for phone numbers I never had...just those here who I already
had the info for.
Thanks!
Jay West
Hi Everyone,
I've been trying to give Jay a link to my PDP11 board, but haven't heard
back from him. When I spoke to him in person, he asked I resend him the
link, and I have several times and haven't heard back so I figured my
mail was getting filtered. Anyway, sorry to spam the list with this,
but I couldn't think of any other way to get ahold of him.
Jay, that address is http://pdpusers.dyndns.org - title is "PDP-11 User
Community" (as I'll be working to get more than just a message board up
on it soon)
Sorry everyone. Thanks Jay!
Julian
