[cctalk] Re: teletype roll as an RF termination load

[Fritz Mueller via cctalk]

> On 6/12/2024 8:28 PM, mark audacity romberg via cctalk wrote:
> Yeah, something’s missing here, teletype paper is for sure not good as a 
> dummy load.



Sounded pretty strange to me, but the commenter is a fairly accomplished person 
in the accelerator electronics and detector division, and the audience (on a 
general channel) was the entire staff of the lab.  So I assume there was 
*something* to the tale...

I wonder what might be missing or lost in translation down the years?  I figure 
if anybody had heard of such a thing, it might be some of this lot :-)

   --FritzM.

[cctalk] Re: teletype roll as an RF termination load

[Gavin Scott via cctalk]

Is it possible they were thinking about really old FAX paper which
might have been wet to support marking via an electric discharge
through it (and to (slightly) reduce the frequency with which the
receiving machine caught fire)?

On Wed, Jun 12, 2024 at 5:56 PM Fritz Mueller via cctalk
 wrote:
>
> So, I recently salvaged a pair of ASR 33s and a PDP-8/I from a research lab 
> where I work.  A few folks chimed in on the "anybody want this" thread, but I 
> happened to be the lucky winner (not lucky for my back or my basement, but 
> they will be fun restoration projects.)
>
> One of the engineers here asked if there were any teletype rolls along with 
> these and if so that they be salvaged because "...it is broadly lossy to rf 
> and can be used as an rf termination load."
>
> When asked a little further if this was teletype rolls in particular, she 
> replied yes, and that this was something she had picked up in former work as 
> an RF engineer at Varian, from a previous generation of crafty engineers.
>
> I thought this was pretty interesting, and that the list here might have a 
> cross-section of folks who might comment.  Anybody heard of this before?
>
> Hmmm, teletypes *and* RF -- sounds like something Marc might want to check 
> out... :-)
>
> cheers,
>   --FritzM.
>
>

[cctalk] Re: teletype roll as an RF termination load

[W2HX via cctalk]

Yes I do rtty and I use mechanical equipment.  Several of us use military 
standards and military equipment.  I show some of this on my Youtube Channel 
which can be found at @w2hx

Sent from Nine


From: ben via cctalk 
Sent: Wednesday, June 12, 2024 11:08 PM
To: cctalk@classiccmp.org
Cc: ben
Subject: [cctalk] Re: teletype roll as an RF termination load

On 2024-06-12 8:17 p.m., Dennis Boone via cctalk wrote:
>   > I wouldn't think it would work much better than a light bulb, though.
>
> Load it up with a wide range tuner, and you could probably make contacts
> across three states, though, just like the light bulb. :)
>
> De
Wow the worlds cheapest RTTY setup, or is it fewest parts.
Does any one do RTTY or slow scan TV now days?
Ben.

[cctalk] Re: teletype roll as an RF termination load

[ben via cctalk]

On 2024-06-12 8:17 p.m., Dennis Boone via cctalk wrote:

  > I wouldn't think it would work much better than a light bulb, though.

Load it up with a wide range tuner, and you could probably make contacts
across three states, though, just like the light bulb. :)

De

Wow the worlds cheapest RTTY setup, or is it fewest parts.
Does any one do RTTY or slow scan TV now days?
Ben.

[cctalk] Re: teletype roll as an RF termination load

[Dennis Boone via cctalk]

 > I wouldn't think it would work much better than a light bulb, though.

Load it up with a wide range tuner, and you could probably make contacts
across three states, though, just like the light bulb. :)

De

[cctalk] Re: teletype roll as an RF termination load

[Will Cooke via cctalk]

> On 06/12/2024 5:55 PM CDT Fritz Mueller via cctalk  
> wrote:
>
>

>
> One of the engineers here asked if there were any teletype rolls along with 
> these and if so that they be salvaged because "...it is broadly lossy to rf 
> and can be used as an rf termination load."
>

> cheers,
> --FritzM.

It's been almost 40 years since I saw a roll of teletype paper, but I think 
they were rolled on cardboard?  I can't imagine it would work very well in its 
native state, but maybe soaked in water or salt water it would be conductive 
enough and could dissipate a fair amount of power.  I wouldn't think it would 
work much better than a light bulb, though.

I know in the army they taught us to make a terminating resistor out of an ear 
plug case filled with salt water, but that wasn't intended to be very accurate 
or dissipate much power.

Will

Grownups never understand anything by themselves and it is tiresome for 
children to be always and forever explaining things to them,

Antoine de Saint-Exupery in The Little Prince

[cctalk] Re: teletype roll as an RF termination load

[Mike Katz via cctalk]

Maybe they are thinking that because it is oil it will work like an oil 
can load.


Sound to me like the originator of this is a big load of dummy

On 6/12/2024 8:28 PM, mark audacity romberg via cctalk wrote:

Yeah, something’s missing here, teletype paper is for sure not good as a dummy 
load.

[cctalk] Re: teletype roll as an RF termination load

[mark audacity romberg via cctalk]

Yeah, something’s missing here, teletype paper is for sure not good as a dummy 
load. 

[cctalk] Re: teletype roll as an RF termination load

[W2HX via cctalk]

"teletype rolls" what, like rolls of paper? They are not effective as dummy 
loads.


Sent from Nine


From: Fritz Mueller via cctalk 
Sent: Wednesday, June 12, 2024 6:56 PM
To: General Discussion: On-Topic and Off-Topic Posts
Cc: Fritz Mueller
Subject: [cctalk] teletype roll as an RF termination load

So, I recently salvaged a pair of ASR 33s and a PDP-8/I from a research lab 
where I work.  A few folks chimed in on the "anybody want this" thread, but I 
happened to be the lucky winner (not lucky for my back or my basement, but they 
will be fun restoration projects.)

One of the engineers here asked if there were any teletype rolls along with 
these and if so that they be salvaged because "...it is broadly lossy to rf and 
can be used as an rf termination load."

When asked a little further if this was teletype rolls in particular, she 
replied yes, and that this was something she had picked up in former work as an 
RF engineer at Varian, from a previous generation of crafty engineers.

I thought this was pretty interesting, and that the list here might have a 
cross-section of folks who might comment.  Anybody heard of this before?

Hmmm, teletypes *and* RF -- sounds like something Marc might want to check 
out... :-)

cheers,
  --FritzM.

[cctalk] teletype roll as an RF termination load

[Fritz Mueller via cctalk]

So, I recently salvaged a pair of ASR 33s and a PDP-8/I from a research lab 
where I work.  A few folks chimed in on the "anybody want this" thread, but I 
happened to be the lucky winner (not lucky for my back or my basement, but they 
will be fun restoration projects.)

One of the engineers here asked if there were any teletype rolls along with 
these and if so that they be salvaged because "...it is broadly lossy to rf and 
can be used as an rf termination load."

When asked a little further if this was teletype rolls in particular, she 
replied yes, and that this was something she had picked up in former work as an 
RF engineer at Varian, from a previous generation of crafty engineers.

I thought this was pretty interesting, and that the list here might have a 
cross-section of folks who might comment.  Anybody heard of this before?

Hmmm, teletypes *and* RF -- sounds like something Marc might want to check 
out... :-)

cheers,
  --FritzM.

[cctalk] Re: Illiac II Library Routine

[Marvin Johnston via cctalk]

First, the date of the report is January 13, 1967.

I don't plan of offering the report for sale. Once I find a good way of 
duplicating the report, I most likely will put the copies on a thumb 
driver and offer them for sale most likely for the price of the thumb 
drive (1 or 2 dollars.) If bitsavers wants copies, that would be great 
since it (they) will be available at no charge.


Thanks for asking!

Marvin

From: Bill Degnan
Subject: [cctalk] Re: Illiac II Library Routine


Marvin
Are these for sale or are you bringing to exhibit?  What year was the Iliac
II library routine published?  I will be at VCFMW this year.
Bill

On Tue, Jun 11, 2024, 11:26 AM Marvin Johnston via cctalk <
cctalk@classiccmp.org> wrote:


   Thanks for the offer,but I'm located in Santa Barbara, CA. My plans
include VCFMW in September where I can bring a slew of his books, etc.
I might add there are some IBM manuals including the 360 and 1401
Fortran II I've seen so far.

Marvin

[cctalk] Dilog Multifunction MQ-100 board

[Douglas Taylor via cctalk]

Hopefully I can find someone who has a manual for this qbus board, if 
not, does anyone have experience with this board?


Summary:

It's a dual width qbus board with 1 DLV11-J port, 32KW Boot room, on 
board LTC circuit and has a 16 pin connector to attach to a front 
panel.  I dumped the prom's and you can see them over on the VCF 
Forum/DEC page.  I used PDP11GUI to probe the I/O space and it looks 
similar to a MXV11-B boot board, with the addition of a serial port, LTC 
and front panel control.   The board has copyright 1986 so it's not that 
old.


I guess a front panel would have; LED for RUN, LED for DC OK, a switch 
for HALT, switch for RESTART and possibly a switch to disable LTC.  The 
board has a couple of 4N25 optocouplers and what signals would need 
isolation?


Yes, I would like to use this put together a working qbus PDP11 using 
either 11/23 or 11/73 CPU, just for fun.


Doug

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Bill Degnan via cctalk]

On Wed, Jun 12, 2024 at 3:09 PM Dave Dunfield via cctalk <
cctalk@classiccmp.org> wrote:

> Bill Degnan wrote:
> > >  Without looking through everything you have first (sorry)is the
> > NorthStar DOS genned for a 2SIO card?
> > Bill
>
> Most of the disk images I have in the Altair emulation are set up to
> communicate via my own homebuilt
> dual-serial card - There might be one set up for the original Mits serial
> card...
>
> The ones with the Horizon emulation are set up for the serial ports build
> into the Horizon,
> and the Vector 1+ images are set up for whatever I had in that machine.
>
> There is a an image of the NorthStar master system distribution disk -
> which has "unpersonalised
> I/O" this is what was first used to get it running on the Altair - it
> boots and hangs in an infinite loop
> at I/O initialization - you halt the system and then toggle in minimal I/O
> functions functions through
> the front panel - then you can restart DOS and get a console prompt, at
> which point you can load
> "fresh" DOS elsewhere in memory, then using the NorthStar monitor, poke in
> your I/O routines,
> then IN(itialize) a fresh disk and save that DOS to it - thereby creating
> a bootable disk that "talks to
> the console".
>
> This is one of things you can do on the "Virtual Altair", do/experience
> what it was was involved
> in getting an OS up on a front-panel system when you didn't already have
> this OS running!
> Something you had to do in the first days, but few people today have done!
> (other then list members or course)
>  I do have information about how to do this included with the emulater!
>
> -Dave
>

Thanks Dave - It has been many years since I genned a N* disk.  I don't
always have success with the port assigning but eventually I get it to work.
Bill

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Dave Dunfield via cctalk]

Bill Degnan wrote:
> >  Without looking through everything you have first (sorry)is the
> NorthStar DOS genned for a 2SIO card?
> Bill

Most of the disk images I have in the Altair emulation are set up to 
communicate via my own homebuilt
dual-serial card - There might be one set up for the original Mits serial 
card...

The ones with the Horizon emulation are set up for the serial ports build into 
the Horizon,
and the Vector 1+ images are set up for whatever I had in that machine.

There is a an image of the NorthStar master system distribution disk - which 
has "unpersonalised
I/O" this is what was first used to get it running on the Altair - it boots and 
hangs in an infinite loop
at I/O initialization - you halt the system and then toggle in minimal I/O 
functions functions through
the front panel - then you can restart DOS and get a console prompt, at which 
point you can load
"fresh" DOS elsewhere in memory, then using the NorthStar monitor, poke in your 
I/O routines,
then IN(itialize) a fresh disk and save that DOS to it - thereby creating a 
bootable disk that "talks to
the console".

This is one of things you can do on the "Virtual Altair", do/experience what it 
was was involved
in getting an OS up on a front-panel system when you didn't already have this 
OS running!
Something you had to do in the first days, but few people today have done! 
(other then list members or course)
 I do have information about how to do this included with the emulater!

-Dave

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Liam Proven via cctalk]

On Thu, 6 Jun 2024 at 06:10, Sellam Abraham via cctalk
 wrote:

>  If you use
> a computer that simultaneously is or can be used by other people via
> multiple concurrent user sessions across whatever signal path, whatever the
> setting, it is *not* "personal".

I disagree. You are trying to make a binary yes/no split when it just ain't so.

Take, say, a Compaq Deskpro 386, a late-'80s desktop. It's indubitably a PC.

Now boot CDOS-386 on it. Plug a couple of terminals into its serial
ports. Now it's a multiuser host. No hardware change.

Stick a DOS floppy in, reboot. It's a single user PC again.

There is no hardware change. Ben Idontneedasurname says if it doesn't
have a multitasking OS it's not a PC.

Who is right?

Neither of you. You are trying to make out this is an absolute split. It's not.

I used DESQview to multitask DOS apps. Resolutely single user. I know
people who used DESQview to run BBSes. Definitely multiuser.
But the _same software_.

But could one ordinary person afford it? At least in some countries,
e.g. where it's made or at least designed? That is a clearer, easier
split, I think.

-- 
Liam Proven ~ Profile: https://about.me/liamproven
Email: lpro...@cix.co.uk ~ gMail/gTalk/FB: lpro...@gmail.com
Twitter/LinkedIn: lproven ~ Skype: liamproven
IoM: (+44) 7624 277612: UK: (+44) 7939-087884
Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053

[cctalk] Re: Intel 8086 - 46 yrs. ago

[Jon Elson via cctalk]

On 6/12/24 03:02, Peter Corlett via cctalk wrote:


Fun factoid: despite modern x86 being clocked ~1000x faster than ye olde
6502, there's not much in it between them when it comes to interrupt
response time. If all goes well, x86 takes "only" a hundred-ish cycles to do
its book-keeping and jump to the ISR, but if SMM is active (spoiler: it
always is and you can't turn it off) then it introduces a massive amount of
extra jitter and all bets are off.

Well, actually the Pentium classic was supposedly designed 
as the flight computer for the F-15, and had VERY good 
interrupt response time of around 5 us.  We know all about 
this as we used it with real time Linux in CNC motion 
control systems.  A big concern was what was the delay and 
jitter from the RTC triggering an interrupt to when the 
servo position counters were read.  It has been a struggle 
to maintain this level of low jitter with newer processors, 
but we have found quite a few that can do it.


Jon

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Bill Degnan via cctalk]

On Wed, Jun 12, 2024 at 10:07 AM Dave Dunfield via cctalk <
cctalk@classiccmp.org> wrote:

> Having some fun reliving the memories ... I'll also mention that I do have
> other emulators for some
> of the classic systems I had on "Daves Old Computers" (look under "DOS
> Widgets")
> again - in case anyone wants to experience actually using one of these
> systems:
>
> NorthStar Horizon (Z80) - also does: Vector 1+
>  NorthStar DOS, CP/M
>
>
>
Without looking through everything you have first (sorry)is the
NorthStar DOS genned for a 2SIO card?
Bill

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Dave Dunfield via cctalk]

Chuck Guzis wrote:
> I never expanded my 8800 beyond the original 4-slot kit with
> limp-wristed power supply.  The construction (I built from the kit) I
> found to be appalling.  More than once I zinged myself brushing against
> the line voltage traces on the front panel board.  And that awful white
> wire.

Mine was "used" and already assembled when I got it.
It had most of the final expansions - I added a few homebrew ones.
Did improve the power supply , and agree completely on the "white wire"
- I used mine LOTS - did much of my earliest software development on it!

-Dave

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Dave Dunfield via cctalk]

Having some fun reliving the memories ... I'll also mention that I do have 
other emulators for some
of the classic systems I had on "Daves Old Computers" (look under "DOS Widgets")
again - in case anyone wants to experience actually using one of these systems:

NorthStar Horizon (Z80) - also does: Vector 1+
 NorthStar DOS, CP/M

Heathkit H8 (8080)
  Hdos, CP/M

Mil MOD8 (8008) - Canadian
 Scelbi BASIC

Dunfield 6809 (6809) [my original portable]
 My own CUBIX OS

There's more software - these are the main OS's and significant

-Dave

[cctalk] Re: Intel 8086 - 46 yrs. ago

[Chuck Guzis via cctalk]

On 6/12/24 01:02, Peter Corlett via cctalk wrote:

> Fun factoid: despite modern x86 being clocked ~1000x faster than ye olde
> 6502, there's not much in it between them when it comes to interrupt
> response time. If all goes well, x86 takes "only" a hundred-ish cycles to do
> its book-keeping and jump to the ISR, but if SMM is active (spoiler: it
> always is and you can't turn it off) then it introduces a massive amount of
> extra jitter and all bets are off.

Which accounts for some members of the NEC V-series having up to 8
alternate sets of registers for fast context switching.  I have no idea
why Intel didn't follow suit with its 80186 variants.

--Chuck

[cctalk] Re: Experience using an Altair 8800 ("Personal computer" from 70s)

[Sellam Abraham via cctalk]

On Tue, Jun 11, 2024, 9:54 PM Chuck Guzis via cctalk 
wrote:

> Still have no idea what to do with
> all that heavy iron--I haven't touched it in perhaps 40 years. I
> congratulate you in finding homes for yours--I doubt that will happen
> with mine.
>
> --Chuck


eBay. Make some retirement cash.

Sellam

[cctalk] Re: Intel 8086 - 46 yrs. ago

[Peter Corlett via cctalk]

On Mon, Jun 10, 2024 at 05:18:56PM +0100, Joshua Rice via cctalk wrote:
[...]
> DEC came across another issue with the PDP-11 vs the VAX. Although the
> pipelined architecture of the VAX was much faster than the PDP-11, the
> actual time for a single instruction cycle was much increased, which led
> to customers requiring real-time operation to stick with the PDP-11, as it
> was much quicker in those operations. This, along with it's large software
> back-catalog and established platform led to the PDP-11 outliving it's
> successor.

Fun factoid: despite modern x86 being clocked ~1000x faster than ye olde
6502, there's not much in it between them when it comes to interrupt
response time. If all goes well, x86 takes "only" a hundred-ish cycles to do
its book-keeping and jump to the ISR, but if SMM is active (spoiler: it
always is and you can't turn it off) then it introduces a massive amount of
extra jitter and all bets are off.