Re: LGP-30 Memory Drum

[Chuck Guzis]

The biggest single plated-media drum that I ever saw was a Univac
FASTRAND II dual-drum unit (counter-rotating) that used movable heads in
an interesting mechanical setup using levers, linkages and solenoids to
decode an 8421-type binary position to a physical position of the heads.
 Said unit was hooked to a Univac 1108.  Univac used drums well into the
1970s, IIRC.  I think the FASTRAND II positioning mechanism was
described in a 1960s FJCC report.

Said FASTRAND was equipped with microphones (known as a "ping" detector)
to detect when heads hit the plated surface.  I suspect that an
oxide-coated drum would have turned the coating to brown dust in a short
time.https://www.cs.auckland.ac.nz/historydisplays/FourthFloor/ReportsAndViewer/Reports/MagneticDrum.pdf

The one I witnessed in operation was installed on the second floor of a
rather elderly building bordered by a busy street.  One of the problems
dogging the installation is that the heads would "ping" every time a big
truck passed by the building.
---
Having bored everyone with an old story, I did a little patent prowling...

http://www.google.com.gh/patents/US2820688 describes the manufacture of
a drum unit.  Iron oxide in a shellac carrier spread on a drum surface,
then machined to the desired profile appears to be described.

http://www.google.com.gh/patents/US2771595 describes the basic idea of
using a magnetic drum to store digital information.

https://www.cs.auckland.ac.nz/historydisplays/FourthFloor/ReportsAndViewer/Reports/MagneticDrum.pdf
 is an interesting document from ERA describing the magnetic drum

One of the issues addressed by several patents is the stability of the
bearings--apparently, slight irregularity in bearing construction (or
wear) can result in disaster.  Something to bear in mind.

If one were re-working an old drum, the traditional way of getting a
smooth even surface is to plate with electroless nickel, then machine
and polish the surface to the desired finish.   This works for any
substrate, as electroless nickel is an auto-catalytic process not
dependent on the electrical properties of the substrate.

FWIW,
Chuck

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Al Kossow]

CW Industries part number is CWR-142-40-0203

On 1/4/17 10:00 PM, Al Kossow wrote:
> 
> 
> On 1/4/17 7:03 PM, Jon Elson wrote:
>> The part number at Digi-Key is
>> CPC40S
> 
> thanks! I didn't know what other vendors still made them besides 3M
> and they are 1/3 the price.
> 
> 

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Al Kossow]

On 1/4/17 7:03 PM, Jon Elson wrote:
> The part number at Digi-Key is
> CPC40S

thanks! I didn't know what other vendors still made them besides 3M
and they are 1/3 the price.

Re: LGP-30 Memory Drum Update

[allison]

On 01/04/2017 09:56 PM, Jon Elson wrote:
> On 01/04/2017 05:24 PM, Cory Heisterkamp wrote:
>>
>> I'm far from an expert, but it certainly looks like an oxide coating
>> to me. I'm reminded of the folklore when IBM was developing the RAMAC
>> and finally had success with a magnetic paint mixed up outside of
>> house. In that case it was easy to apply...just spin up the disc and
>> pour!
>>
>>
>>
>> http://www.radar58.com/temp/drum.jpg
>> http://www.radar58.com/temp/drum2.jpg
> Yup, that looks pretty "oxidey" all right!
>
> Jon
>
Based on more than a few drums and disks i've seen its oxide, not plated.
I'd also say if the scratches are not deep a little polishing may be the
trick.

I'D do nothing until it can be run up (remove all dust and gunk) and
then look
at the output of the heads.  Likely you don't have to write clock tracks
if there
is mechanical (tone wheel).  If so that means the clock is created there
so its
always in sync with drum rotation.  That's one less headache.

I have a hunch that the data/instruction tracks are not pre-recorded and
can be
over wrote and replaced at will but there is where the manuals and a
thorough
understanding of the machine and its logic is needed.

IF the data tracks are created by other timing (clock and logic) then
erasing
a track is safe (check manuals) and then you can write a track with F and 2F
and see if it reads out uniformly if it does that head is good and the
media
under it is.  Step and repeat, any that fail or have to many drop outs
or other
errors need care, relocate first and try again.

This is about what old school tricks need to be found out about and
relearned.
The closest analogy is how to steam and repair a coal fired locomotive. 
There
is hand me down knowledge that will be needed and learned or even
regenerated.

A very interesting project.

Allison

LC8-P (M8365) PDP8 printer interface schematics

[David Gesswein]

I would also be interested in schematics. I have just started looking at this
board to try to use it with a ODEC/Data 100 chain printer.

> Looking at the LA180 manual's description of the LC8-P interface, it
> is pretty close to Centronics. I expect it is more than just a cable,
> though, because there is also an OMNIBUS Centronics printer interface
> board (LS8-E). That schematic is on bitsavers.
>
It looked to me the LA180 protocol is demand and busy high when ok
to send character then the data is strobed in with data strobe pulse.

Centronics is handshaked with strobe and busy so a little different.

The board is simple enough that tracing it out is feasible if needed.
Haven't plugged in the board yet to see how the signals behave.
Still working on the printer.

Re: LGP-30 Memory Drum Update

[allison]

On 01/04/2017 03:50 PM, Paul Koning wrote:
>> On Jan 4, 2017, at 2:48 PM, Kyle Owen  wrote:
>>
>> On Wed, Jan 4, 2017 at 12:06 PM, Jon Elson  wrote:
>>> Previous messages suggested the LGP-30 drum was plated with nickel. If
>>> there are amateur astronomers with a vacuum evaporator, it might be
>>> possible to get them to adjust their setup slightly to vacuum evaporate
>>> nickel on your drum, after refinishing the base.  You'd need a rig to
>>> slowly turn the drum while evaporating the nickel. Some other research labs
>>> at universities might have the necessary equipment, also - check with the
>>> Physics department (or electrical engineering).
>>
>> Will the desired thickness be enough with sputtering or evaporation? For
>> modern hard drives, sure, but my gut instinct is that you'd want a thicker
>> coating on the drum. I'd suggest sputtering over evaporation since it will
>> probably adhere to the surface better. I'd think nickel electroplating
>> would take less time and effort, though.
> Electroplating sounds ok, I don't know about procedures.  You'd have to be 
> careful that the electrolyte doesn't damage the drum body.
>
> Evaporation and sputtering are used to make well controlled thin films, but 
> there's nothing I can think of that limits how long you continue.  A mirror 
> is coated only to the point that its reflection coefficient reaches the limit 
> of the metal used, more is not useful.  But here you could just keep going 
> however long you need.
>
> As for adhering, both should produce good coatings if the substrate is clean. 
>  I remember a test for good evaporative coating technique: coat a test piece, 
> then try to rip off the coating with scotch tape.  It shouldn't be affected 
> at all by that test.
>
> There are reasons for using sputtering vs. evaporation, but I don't remember 
> them.  I think the Strong book I cited discusses the subject. 

Several things.  Getting aluminum clean and keeping it so means NO
oxygen, it develops a
oxide coating really fast.  Other metal might be used but your generally
limited to non magnetic
substrates (aluminum, glass, brass, bronze).

Also the thickness of the magnetic media, rate of travel (speed relative
to the head),  head
distance and gap are all interrelated. For heads of that era the gap
will be wide, the media
thick, and the rate of travel high.  Those factors determine bit density
(likely very low) and
the data rate is really low as the machine is slow.

If the drum is scratched then moving heads one gap width right or left
should do fine.

Plated media doesn't help with this save for its mechanically easier to do.

Allison




>   paul
>
>
>

Re: LGP-30 Memory Drum Update

[Jon Elson]

On 01/04/2017 05:24 PM, Cory Heisterkamp wrote:


I'm far from an expert, but it certainly looks like an oxide coating to me. I'm 
reminded of the folklore when IBM was developing the RAMAC and finally had 
success with a magnetic paint mixed up outside of house. In that case it was 
easy to apply...just spin up the disc and pour!



http://www.radar58.com/temp/drum.jpg
http://www.radar58.com/temp/drum2.jpg

Yup, that looks pretty "oxidey" all right!

Jon

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[steve shumaker]

On 1/4/2017 10:09 AM, Jon Elson wrote:

On 01/04/2017 09:08 AM, Al Kossow wrote:
I need some of these for making Diablo disk drive cables. 
Mouser/Digikey, etc. have a

minimum buy of 500 (at $9 ea).

Picture at 
http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connector.jpg


Anyone see any at any surplus places? Online searches are pretty much 
useless because
of the extremely common 40 pin male IDC plug, and my searches in the 
valley have come

up empty.



Hmmm, Digi-Key used to make cables to order with this type of 
termination.  Surprised they don't have the parts anymore.


Jon

Weird Stuff in San Jose commonly has a variety of floppy cables.   I 
usually deal in person but you might give them a call or leave a query 
on their web page



steve

Re: LGP-30 Memory Drum Update

[jim stephens]

On 1/4/2017 7:56 AM, allison wrote:
Sperm oil was a high quality wax/lubricant. Its low viscosity and high 
resistance to oxidation
were its high points.  Its likely use was as a plasticize the binder 
and surface. 
As far as I know it is illegal to purchase or transfer now.  Not to 
possess.  I have the supply my father had because he was a watchmaker.  
he had bought a lifetime supply in the 40's and it is still 90% there.  
But I can't transfer it.


He used a very small drop in a small dimple holder with a cap over it 
for about a year.  A sharp needle provided all that was placed on watch 
bearings.


I'm sure it would be ideal for this application, but can only agree with 
Allison about the properties of it now days.


thanks
Jim

Re: LGP-30 Memory Drum Update

[Cory Heisterkamp]

On Jan 4, 2017, at 1:02 PM, allison wrote:

> On 1/4/17 1:06 PM, Jon Elson wrote:
>> On 01/04/2017 09:03 AM, Klemens Krause wrote:
>>> 
>>> 
 We both have analog recordings (from digitizing scopes) and logic analyzer 
 dumps. So concerning the LGP-30, all relevant information about the drum 
 has been saved :-)
 
>>> 
>>> We have a second LGP-30 drum in our museum. It is damaged by water.
>>> (large rusted areas, probably from water between heads and drum).
>>> I'm dreaming to wash the brown oxide coating off with a solvent like
>>> acetone, polish the drum and repaint it.
>>> As magnetic paint I would try iron oxide from audio tapes solved in acetone 
>>> or some other solvent.
>>> Perhaps one could ask an airbrush artist to do this.
>>> Rumours say, that the drums originally also were coated "by hand".
>>> Rewriting the timing tracks should not be impossible with todays
>>> electronics.
>>> There is another guy here in germany, who has a LGP-30 with heavily
>>> corroded drum. That would be certainly interesting for him.
>>> 
>> Previous messages suggested the LGP-30 drum was plated with nickel. If there 
>> are amateur astronomers with a vacuum evaporator, it might be possible to 
>> get them to adjust their setup slightly to vacuum evaporate nickel on your 
>> drum, after refinishing the base. You'd need a rig to slowly turn the drum 
>> while evaporating the nickel. Some other research labs at universities might 
>> have the necessary equipment, also - check with the Physics department (or 
>> electrical engineering).
>> 
>> Jon

I'm far from an expert, but it certainly looks like an oxide coating to me. I'm 
reminded of the folklore when IBM was developing the RAMAC and finally had 
success with a magnetic paint mixed up outside of house. In that case it was 
easy to apply...just spin up the disc and pour!

There are a couple of 1" long spots where the coating was scraped away and the 
heads relocated. Given what I've read about the Control Data badged LGP-30's, 
this was likely a refurb sold in the 60's. The replacement heads certainly 
support that. Below are some pics of my drum; the tonewheel clock generator can 
be seen at the far right. The groove just to the left of that leaving a single 
band in the mag material is too perfect to be a goof, but at the 0.4" head 
offset spacing, is too narrow to contain more than one track.  -C

http://www.radar58.com/temp/drum.jpg
http://www.radar58.com/temp/drum2.jpg

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Al Kossow]

On 1/4/17 10:33 AM, Marc Howard wrote:
> I know I've bought these in the past 3 years at Excess Solutions (www.
> *excesssolutions*.com).
> 

I'll check again, but I didn't see them.
They have turned a lot of stock, or didn't put it out after they moved to San 
Jose
I may have to ask Mike if he's seen any.

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Marc Howard]

I know I've bought these in the past 3 years at Excess Solutions (www.
*excesssolutions*.com).

They used to be close to where I work in Milpitas but now they're south of
downtown San Jose in a trucking warehouse
and not as easy to visit.

Marc

On Wed, Jan 4, 2017 at 10:09 AM, Jon Elson  wrote:

> On 01/04/2017 09:08 AM, Al Kossow wrote:
>
>> I need some of these for making Diablo disk drive cables. Mouser/Digikey,
>> etc. have a
>> minimum buy of 500 (at $9 ea).
>>
>> Picture at http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connec
>> tor.jpg
>>
>> Anyone see any at any surplus places? Online searches are pretty much
>> useless because
>> of the extremely common 40 pin male IDC plug, and my searches in the
>> valley have come
>> up empty.
>>
>>
>>
>> Hmmm, Digi-Key used to make cables to order with this type of
> termination.  Surprised they don't have the parts anymore.
>
> Jon
>

Re: LGP-30 Memory Drum Update

[Charles Anthony]

On Wed, Jan 4, 2017 at 12:30 PM, Chuck Guzis  wrote:

> On 01/04/2017 11:48 AM, Kyle Owen wrote:
>
> > Will the desired thickness be enough with sputtering or evaporation?
> > For modern hard drives, sure, but my gut instinct is that you'd want
> > a thicker coating on the drum. I'd suggest sputtering over
> > evaporation since it will probably adhere to the surface better. I'd
> > think nickel electroplating would take less time and effort, though.
> >
> > Heck, I have about 4 L of nickel plating solution as well as an
> > anode, if someone wants to give it a shot.
>
>
> Thinking more about this a bit...
>
> "Modern" aluminum-substrate plated media uses a layer of electroless
> nickel, which is then polished, then plated with a layer of electroless
> cobalt.   I don't know if cobalt can be vacuum-sputtered onto nickel.
>
> Lubrication layers are often added in the case of Winchester drives.
>
> I suspect that the LGP30 drum heads require a substantial signal, so
> perhaps 5 micron cobalt plating wouldn't work.  In any case, the low
> recording density might be better realized through a traditional
> iron-oxide-in-binder coating.
>
>
I am not a EE, but in a ignorant attempt at of the box thinking.

Make a new drum out of AL, glue strips of COTS magnetic tape to it.

-- Charles

Re: LGP-30 Memory Drum Update

[Paul Koning]

> On Jan 4, 2017, at 2:48 PM, Kyle Owen  wrote:
> 
> On Wed, Jan 4, 2017 at 12:06 PM, Jon Elson  wrote:
>> 
>> Previous messages suggested the LGP-30 drum was plated with nickel. If
>> there are amateur astronomers with a vacuum evaporator, it might be
>> possible to get them to adjust their setup slightly to vacuum evaporate
>> nickel on your drum, after refinishing the base.  You'd need a rig to
>> slowly turn the drum while evaporating the nickel. Some other research labs
>> at universities might have the necessary equipment, also - check with the
>> Physics department (or electrical engineering).
> 
> 
> Will the desired thickness be enough with sputtering or evaporation? For
> modern hard drives, sure, but my gut instinct is that you'd want a thicker
> coating on the drum. I'd suggest sputtering over evaporation since it will
> probably adhere to the surface better. I'd think nickel electroplating
> would take less time and effort, though.

Electroplating sounds ok, I don't know about procedures.  You'd have to be 
careful that the electrolyte doesn't damage the drum body.

Evaporation and sputtering are used to make well controlled thin films, but 
there's nothing I can think of that limits how long you continue.  A mirror is 
coated only to the point that its reflection coefficient reaches the limit of 
the metal used, more is not useful.  But here you could just keep going however 
long you need.

As for adhering, both should produce good coatings if the substrate is clean.  
I remember a test for good evaporative coating technique: coat a test piece, 
then try to rip off the coating with scotch tape.  It shouldn't be affected at 
all by that test.

There are reasons for using sputtering vs. evaporation, but I don't remember 
them.  I think the Strong book I cited discusses the subject. 

paul

Re: LC8-P (M8365) PDP8 printer interface schematics

[Charles Dickman]

On Wed, Jan 4, 2017 at 7:08 AM, Christian Corti
 wrote:
> On Tue, 3 Jan 2017, Ethan Dicks wrote:
>>
>> On Tue, Jan 3, 2017 at 8:04 PM, Charles Dickman  wrote:
>>>
>>> I am looking for schematics or any documentation for the LA180
>>> interface for the PDP8/e. A scan would be great. I want to see if I
>>> can use it to interface to a Centronics interface printer.
>>
>>
>> I don't have the schematics (I do have an LC8-P somewhere), but I
>> remember back in the day, people wanted to go the other way - feed a
>> PC printer w/Centronics interface from a DEC interface.
>
>
> It's not the other way, it's the same way ;-) (attatching a Centronics/PC
> printer to a DEC interface)

Yes, I want to connected an OKIDATA Microline82A to the PDP8/e.

Looking at the LA180 manual's description of the LC8-P interface, it
is pretty close to Centronics. I expect it is more than just a cable,
though, because there is also an OMNIBUS Centronics printer interface
board (LS8-E). That schematic is on bitsavers.

I also have an LE8-E (M841), but that only provides 7 data bits to the printer.

-chuck

Re: LGP-30 Memory Drum Update

[Chuck Guzis]

On 01/04/2017 11:48 AM, Kyle Owen wrote:

> Will the desired thickness be enough with sputtering or evaporation?
> For modern hard drives, sure, but my gut instinct is that you'd want
> a thicker coating on the drum. I'd suggest sputtering over
> evaporation since it will probably adhere to the surface better. I'd
> think nickel electroplating would take less time and effort, though.
> 
> Heck, I have about 4 L of nickel plating solution as well as an
> anode, if someone wants to give it a shot.


Thinking more about this a bit...

"Modern" aluminum-substrate plated media uses a layer of electroless
nickel, which is then polished, then plated with a layer of electroless
cobalt.   I don't know if cobalt can be vacuum-sputtered onto nickel.

Lubrication layers are often added in the case of Winchester drives.

I suspect that the LGP30 drum heads require a substantial signal, so
perhaps 5 micron cobalt plating wouldn't work.  In any case, the low
recording density might be better realized through a traditional
iron-oxide-in-binder coating.

--Chuck

Re: LGP-30 Memory Drum Update

[Kyle Owen]

On Wed, Jan 4, 2017 at 12:06 PM, Jon Elson  wrote:
>
> Previous messages suggested the LGP-30 drum was plated with nickel. If
> there are amateur astronomers with a vacuum evaporator, it might be
> possible to get them to adjust their setup slightly to vacuum evaporate
> nickel on your drum, after refinishing the base.  You'd need a rig to
> slowly turn the drum while evaporating the nickel. Some other research labs
> at universities might have the necessary equipment, also - check with the
> Physics department (or electrical engineering).


Will the desired thickness be enough with sputtering or evaporation? For
modern hard drives, sure, but my gut instinct is that you'd want a thicker
coating on the drum. I'd suggest sputtering over evaporation since it will
probably adhere to the surface better. I'd think nickel electroplating
would take less time and effort, though.

Heck, I have about 4 L of nickel plating solution as well as an anode, if
someone wants to give it a shot.

Kyle

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Jon Elson]

On 01/04/2017 09:08 AM, Al Kossow wrote:

I need some of these for making Diablo disk drive cables. Mouser/Digikey, etc. 
have a
minimum buy of 500 (at $9 ea).

Picture at http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connector.jpg

Anyone see any at any surplus places? Online searches are pretty much useless 
because
of the extremely common 40 pin male IDC plug, and my searches in the valley 
have come
up empty.



Hmmm, Digi-Key used to make cables to order with this type 
of termination.  Surprised they don't have the parts anymore.


Jon

Re: LGP-30 Memory Drum Update

[Jon Elson]

On 01/04/2017 09:03 AM, Klemens Krause wrote:



We both have analog recordings (from digitizing scopes) 
and logic analyzer dumps. So concerning the LGP-30, all 
relevant information about the drum has been saved :-)




We have a second LGP-30 drum in our museum. It is damaged 
by water.
(large rusted areas, probably from water between heads and 
drum).
I'm dreaming to wash the brown oxide coating off with a 
solvent like

acetone, polish the drum and repaint it.
As magnetic paint I would try iron oxide from audio tapes 
solved in acetone or some other solvent.

Perhaps one could ask an airbrush artist to do this.
Rumours say, that the drums originally also were coated 
"by hand".
Rewriting the timing tracks should not be impossible with 
todays

electronics.
There is another guy here in germany, who has a LGP-30 
with heavily

corroded drum. That would be certainly interesting for him.

Previous messages suggested the LGP-30 drum was plated with 
nickel. If there are amateur astronomers with a vacuum 
evaporator, it might be possible to get them to adjust their 
setup slightly to vacuum evaporate nickel on your drum, 
after refinishing the base.  You'd need a rig to slowly turn 
the drum while evaporating the nickel. Some other research 
labs at universities might have the necessary equipment, 
also - check with the Physics department (or electrical 
engineering).


Jon

Re: LGP-30 Memory Drum Update

[Jon Elson]

On 01/04/2017 06:05 AM, Christian Corti wrote:


The LGP-30 is similar, but the timing and long tracks 
(i.e. main memory) are not recirculating. Hence the reason 
why a word is limited to 31 bits, although the sector 
holds 32 bits. The last bit must be zero to reset the read 
circuitry for the next sector.


So, there is no inter-word gap to accommodate the write head 
switching?  I guess if everything is hard-synched to the 
clock track, then you can get away without that.  Interesting!


Jon

Re: LGP-30 Memory Drum Update

[Klemens Krause]

On Wed, 4 Jan 2017, Al Kossow wrote:




On 1/4/17 7:03 AM, Klemens Krause wrote:


We have a second LGP-30 drum in our museum. It is damaged by water.



...


In doing some disk research recently, I came across a footnote for a rather 
unlikely
place to find information on magnetic coatings, which I just got a copy of:

Patton "Pigment Handbook Volume II Applications and Markets"  1973

Kurt Kreiselmaier "Pigmentation of Magnetic Tapes" pp 315-329


Nice, the book is available in our library here at the university.
I'll get it tomorrow from the magazine. :_


Klemens


--

klemens krause
Stuttgarter KompetenzZentrum fyr Minimal- & Retrocomputing.
http://computermuseum.informatik.uni-stuttgart.de

Re: Where are the cctech archives before November 2014 ?

[Walter F.J. Mueller]

Hi,

after I remarked in November last year that the cctech archives have been `lost`
Jay West responded

> Walter
>
> I think you need to ask a few questions before you toss that kind of nonsense 
out.
>
> For your info - this is a hobby. It is done in spare time. The time period you
> peak of - the archives have NOT been lost. Because unlike what you intone - we
> do care. Those archives are safe and sound, just not in a publicly accessible
> format. One of our kind list members has been working for eons to reconstruct
> the publicly viewable content from them.
>
> I will tell him that you are going to volunteer to help him.

Well, it is certainly true that the archives visible under
  http://www.classiccmp.org/pipermail/cctech/
only go back to November 2014.

Thanks to the Internet Archive there is a full backup of the older
archive sections readily available online. Simply open

  
http://web.archive.org/web/20141025062159/http://www.classiccmp.org/pipermail/cctech/

and one gets all archives from October 2014 back to February 2005.

There I found the postings I was looking for, and updated my links to use
http://web.archive.org/. That's all.

So in a wider sense nothing is lost, one has to search in the right place.

With best regards,  Walter

Re: LGP-30 Memory Drum Update

[allison]

On 1/4/17 10:19 AM, Al Kossow wrote:


On 1/4/17 7:03 AM, Klemens Krause wrote:


We have a second LGP-30 drum in our museum. It is damaged by water.
(large rusted areas, probably from water between heads and drum).
I'm dreaming to wash the brown oxide coating off with a solvent like
acetone, polish the drum and repaint it.
As magnetic paint I would try iron oxide from audio tapes solved in acetone or 
some other solvent.
Perhaps one could ask an airbrush artist to do this.
Rumours say, that the drums originally also were coated "by hand".

The was a post application "calendaring" process to get a uniform smooth 
surface.



In doing some disk research recently, I came across a footnote for a rather 
unlikely
place to find information on magnetic coatings, which I just got a copy of:

Patton "Pigment Handbook Volume II Applications and Markets"  1973

Kurt Kreiselmaier "Pigmentation of Magnetic Tapes" pp 315-329

Which goes through the whole process at a high level of how magnetic tape is 
made,
including aligning all the magnetic particles on the surface. They also mention 
sperm
oil being used as one of the ingredients (I had wondered if there was 
documentation
for that claim), and about two dozen patents at the end.
Sperm oil was a high quality wax/lubricant. Its low viscosity and high 
resistance to oxidation
were its high points.  Its likely use was as a plasticize the binder and 
surface.



There is also a lot of information in the book on colorizing agents for 
plastics.

I'll put a scan up today under midwesternUniveristy, where Kreiselmaier was an 
asst prof.

Re: ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Tony Duell]

On Wed, Jan 4, 2017 at 3:08 PM, Al Kossow  wrote:
> I need some of these for making Diablo disk drive cables. Mouser/Digikey, 
> etc. have a
> minimum buy of 500 (at $9 ea).
>
> Picture at http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connector.jpg
>
> Anyone see any at any surplus places? Online searches are pretty much useless 
> because
> of the extremely common 40 pin male IDC plug, and my searches in the valley 
> have come
> up empty.

Farnell _used_ to sell them, but now claim 'no longer manufactured' :-(

When I needed one years ago (and RS/Farnell didn't take private orders), I ended
up separating the ribbon cable into individual wires and soldering each one into
the right PCB hole...

-tony

Re: LGP-30 Memory Drum Update

[Al Kossow]

On 1/4/17 7:03 AM, Klemens Krause wrote:

> We have a second LGP-30 drum in our museum. It is damaged by water.
> (large rusted areas, probably from water between heads and drum).
> I'm dreaming to wash the brown oxide coating off with a solvent like
> acetone, polish the drum and repaint it.
> As magnetic paint I would try iron oxide from audio tapes solved in acetone 
> or some other solvent.
> Perhaps one could ask an airbrush artist to do this.
> Rumours say, that the drums originally also were coated "by hand".
> 

In doing some disk research recently, I came across a footnote for a rather 
unlikely
place to find information on magnetic coatings, which I just got a copy of:

Patton "Pigment Handbook Volume II Applications and Markets"  1973

Kurt Kreiselmaier "Pigmentation of Magnetic Tapes" pp 315-329

Which goes through the whole process at a high level of how magnetic tape is 
made,
including aligning all the magnetic particles on the surface. They also mention 
sperm
oil being used as one of the ingredients (I had wondered if there was 
documentation
for that claim), and about two dozen patents at the end.

There is also a lot of information in the book on colorizing agents for 
plastics.

I'll put a scan up today under midwesternUniveristy, where Kreiselmaier was an 
asst prof.

Re: LC8-P (M8365) PDP8 printer interface schematics

[Ethan Dicks]

On Wed, Jan 4, 2017 at 7:08 AM, Christian Corti
 wrote:
> On Tue, 3 Jan 2017, Ethan Dicks wrote:
>>
>> On Tue, Jan 3, 2017 at 8:04 PM, Charles Dickman  wrote:
>>> I want to see if I can use it to interface to a Centronics interface 
>>> printer.
>>
>> ... but I remember back in the day, people wanted to go the other way - feed 
>> a
>> PC printer w/Centronics interface from a DEC interface.
>
> It's not the other way, it's the same way ;-) (attatching a Centronics/PC
> printer to a DEC interface)

Ah, yes... I was thinking about a Usenet article from long ago
describing the other way.

Enjoy!

-ethan

ISO small quantity of 3M 3418 40 pin pcb to ribbon male connectors

[Al Kossow]

I need some of these for making Diablo disk drive cables. Mouser/Digikey, etc. 
have a
minimum buy of 500 (at $9 ea).

Picture at http://multimedia.3m.com/mws/media/140452P/ts0005-pcb-connector.jpg

Anyone see any at any surplus places? Online searches are pretty much useless 
because
of the extremely common 40 pin male IDC plug, and my searches in the valley 
have come
up empty.

Re: LGP-30 Memory Drum Update

[Klemens Krause]

On Wed, 4 Jan 2017, Christian Corti wrote:


On Tue, 3 Jan 2017, Al Kossow wrote:
There are running LGP-30s. Should be short work with a digital oscillosope 



We both have analog recordings (from digitizing scopes) and logic analyzer 
dumps. So concerning the LGP-30, all relevant information about the drum has 
been saved :-)




We have a second LGP-30 drum in our museum. It is damaged by water.
(large rusted areas, probably from water between heads and drum).
I'm dreaming to wash the brown oxide coating off with a solvent like
acetone, polish the drum and repaint it.
As magnetic paint I would try iron oxide from audio tapes solved in 
acetone or some other solvent.

Perhaps one could ask an airbrush artist to do this.
Rumours say, that the drums originally also were coated "by hand".
Rewriting the timing tracks should not be impossible with todays
electronics.
There is another guy here in germany, who has a LGP-30 with heavily
corroded drum. That would be certainly interesting for him.

Klemens


--

klemens krause
Stuttgarter KompetenzZentrum fyr Minimal- & Retrocomputing.
http://computermuseum.informatik.uni-stuttgart.de

Re: LC8-P (M8365) PDP8 printer interface schematics

[Christian Corti]

On Tue, 3 Jan 2017, Ethan Dicks wrote:

On Tue, Jan 3, 2017 at 8:04 PM, Charles Dickman  wrote:

I am looking for schematics or any documentation for the LA180
interface for the PDP8/e. A scan would be great. I want to see if I
can use it to interface to a Centronics interface printer.


I don't have the schematics (I do have an LC8-P somewhere), but I
remember back in the day, people wanted to go the other way - feed a
PC printer w/Centronics interface from a DEC interface.


It's not the other way, it's the same way ;-) (attatching a Centronics/PC 
printer to a DEC interface)


Christian

Re: Fix for 4.3BSD-Quasijarus bootstrap on CMD SCSI controllers

[Lars Brinkhoff]

I wonder if GNU Emacs 16/17, or Gosling Emacs runs 4.3BSD?

I could set up an emulator, but if you guys already have it running,
maybe you'd like to give it a shot?

GNU Emacs 16.56 and 17.62.

https://github.com/larsbrinkhoff/emacs-history/raw/unixpc/ftp.splode.com/pub/users/friedman/emacs/emacs-16.56.tar.gz
https://github.com/larsbrinkhoff/emacs-history/raw/unixpc/bitsavers.org/bits/DEC/vax/ultrix/3.0/emacs-17.62.1-ultrix.tar.z

Gosling Emacs.  These are modified, not sure if they retain support for
the Unix systems they originally ran on.

https://github.com/larsbrinkhoff/emacs-history/raw/unixpc/der%20Mouse/gosling-emacs.tar
https://github.com/larsbrinkhoff/emacs-history/raw/unixpc/reid.org/%7Ebrian/misc/gosling-emacs-1999.tar

AT UNIX PC binaries for Montgomery Emacs, cpio archive.

https://github.com/larsbrinkhoff/emacs-history/blob/unixpc/unixpc.taronga.com/STORE/EMACS%2BIN.gz

Re: LGP-30 Memory Drum Update

[Christian Corti]

On Tue, 3 Jan 2017, Paul Koning wrote:
The key questions for reconstructing such a device is what the 
modulation scheme is, and the pulse pattern.  There might be marker 
pulses for sector start, for example, or that might just be derived from 
a counter in the controller.


It's in the maintenance manual. There is one flux change for a one bit, 
and a flux change to the opposite direction for a zero bit.
All timing is derived from the timing tracks S1..S3. The magic box to 
reconstruct these timing tracks must be synchronized to the base clock 
coming from the drum (137 kHz on European machines). The base clock is 
picked up with a special read head, the clock bits are "engraved" into the 
drum cylinder, so no need to write this clock track.


Christian

Re: was: National Semi... is Apple ][ collectability (if any)

[Eric Smith]

On Tue, Jan 3, 2017 at 9:03 PM, drlegendre .  wrote:

> Add some RAM, maybe a DISC-II card and those things overheated even +with+
> the vents.. that's why the Cider fan became popular, among other things.
>

My Apple II+ had no fan, but never overheated. I heard a lot of people talk
about needing a fan, but had no idea why.

For much of its life my Apple II+ contained:
0:  language card (16KB DRAM)
1:  parallel printer card
2:  super serial card
3:  Videx 80-column card
4:  Microsoft Z-80 softcard
5:  homemade HP-IL interface card using HP 1LB3 chip
6:  Disk II controller
7:  Sorrento Valley 8-inch floppy disk controller
and a Videx Keyboard Enhancer II (6502-based replacement for the Apple
keyboard encoder, to add lower case, macros, etc.)

The only times I had any unreliability were when one DRAM chip went bad,
and when the firmware EPROM (2708) on the Videx card went bad.

At other points in time it contained
* Corvus hard disk interface
* Apple Profile hard disk interface
* Video Associate Labs VB3 microkeyer (large board in slot 7, cabled to an
even larger board over the power supply)

If anything was going to make it overheat, I would have bet on the VB3.

Re: Fix for 4.3BSD-Quasijarus bootstrap on CMD SCSI controllers

[David Brownlee]

On 4 January 2017 at 11:19, David Brownlee  wrote:
> On 4 January 2017 at 08:13, Holm Tiffe  wrote:
>>
>> Could please someone check this file:
>>
>> http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.gz
>> (or this one:
>> http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.Z)
>> against the repo?
>>
>> If I remember correctly it contains some patches from Michael Sokolov not
>> contained in 0c.
>> I've had some conversations with him in the past, had a 0c running on a
>> KA630 System with Emulex UC08 and a 8Gig Tandberg Tape drive.
>
> Great - will merge them in :)

Thanks, 'tis done. I've excluded the .o files outside of /sys

https://github.com/abs0/4.3BSD-Quasijarus/releases

David

Re: Fix for 4.3BSD-Quasijarus bootstrap on CMD SCSI controllers

[David Brownlee]

On 4 January 2017 at 08:13, Holm Tiffe  wrote:
> David Brownlee wrote:
>
>> On 3 January 2017 at 20:11, David Brownlee  wrote:
>> > On 3 January 2017 at 15:50, Noel Chiappa  wrote:
>> >> > From: Josh Dersch
>> >>
>> >> > Thought I'd share this fix with you all just in case someone in the
>> >> > future might make use of it.
>> >>
>> >> To help disseminate it, I uploaded the fix to the Computer History wiki:
>> >>
>> >>   http://gunkies.org/wiki/CDU-710/M_disk_controller
>> >>
>> >>
>> >> > From: Lars Brinkhoff
>> >>
>> >> > There's no central repository for fixes like these?
>> >>
>> >> Well, the CH wiki would be a good place, but creating new accounts on it 
>> >> is
>> >> proving to be difficult.
>> >>
>> >> I'm trying to get ahold of one of the two bureacrats, to make me an admin
>> >> (I've been one on Wikipedia since the Devonian), so I can create accounts 
>> >> for
>> >> people, but so far no luck.
>> >>
>> >> Noel
>> >
>> > Would it make sense for someone to import it to github?
>> >
>> > If nothing else it should be be easy enough to start with 0, then
>> > update to 0a 0b and then 0c. so we have what history is available.
>> >
>> > (checks github)
>> >
>> > Aha - I see that johnwfinigan has already put up a 0c, though it
>> > doesn't seem to have the 0, 0a & 0b history
>> > https://github.com/johnwfinigan/4.3BSD-quasijarus0c/commits/master
>> >
>> > Actually I might just do the 0..0c history into a github entry myself,
>> > then anyone else can just {v,}fork and take it from there as desired :-p
>>
>> No sooner said than done :)
>>
>> In case it proves of interest to anyone. Happy for it to be forked
>> (obviously!) or to have patches or pull requests punted back to me
>>
>> https://github.com/abs0/4.3BSD-Quasijarus
>>
>> David
>
> Could please someone check this file:
>
> http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.gz
> (or this one:
> http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.Z)
> against the repo?
>
> If I remember correctly it contains some patches from Michael Sokolov not
> contained in 0c.
> I've had some conversations with him in the past, had a 0c running on a
> KA630 System with Emulex UC08 and a 8Gig Tandberg Tape drive.

Great - will merge them in :)

Re: was: National Semi... is Apple ][ collectability (if any)

[drlegendre .]

My first encounter with Apple II was in 1978 or so, when we got 2 units at
my school. They were each fitted with a pair of Disc II units, and what
must have been an 8" B CCTV monitor.

Both floppy drives, plus the monitor were heaped atop the rear portion of
the Apple II case; drives to the left, monitor to the right, best of my
recall. Learned my first BASIC and so forth on those machines.

On Wed, Jan 4, 2017 at 1:03 AM, Brad H 
wrote:

>
>
>  Original message 
> From: "drlegendre ." 
> Date: 2017-01-03  8:03 PM  (GMT-08:00)
> To: "General Discussion: On-Topic and Off-Topic Posts" <
> cctalk@classiccmp.org>
> Subject: Re: was: National Semi... is Apple ][ collectability (if any)
>
> "Vent-less case" - LoL!!
>
> Add some RAM, maybe a DISC-II card and those things overheated even +with+
> the vents.. that's why the Cider fan became popular, among other things.
>
> When I was in high school, we'd pop the case tops open, and run them that
> way. Otherwise, they'd overheat and start screwing up after the first or
> second class period.
>
> On Tue, Jan 3, 2017 at 10:36 AM, Brad H  bettercomputing.net
> > wrote:
>
> > >On 1/2/2017 11:26 PM, Brad H wrote:
> > > I brought the RFI thing up with him.  No response.  There is a legit
> Rev
> > 1 there too asking $3500.  I don't find Apple IIs below Rev 0 that
> > interesting anymore, personally.  I think even the legit guy would
> struggle
> > to get much above $1500.
> > >The vintagecomputer museum guy on epay is selling mounted and framed
> > motherboards now for $1500 (might not >work noted).
> >
> > >I guess someone would care about low ref Apple 2's but I'm not sure why
> > there would be any interest.  I've got one >I bought with the original
> > packing box, which I have picked and moved twice, which is rare for my
> > collecting, but I >don't know what makes any Apple 2 like that
> > collectible.  As in why are they collectible with low serials / part
> > >numbers.
> >
> > >is there any documentation as to when they were made with those numbers
> > that would make them significant?  >The numbers made as Raymond said
> would
> > make most of us with Apple 2's millionaires I'd think unless they have
> > >some other significance.
> >
> > >just curious.
> > >thanks
> > >Jim
> >
> > When I got into collecting an original Apple II was as rare as hen's
> teeth
> > on ebay, etc.  Those got huge bucks, regardless of rev.  Then sellers
> > caught on and stuff started coming out of closets, basements, estate
> > sales.  I actually track Apple II sales and prices have massively
> declined
> > since 15 years ago.  I mean, there's 6+ out there theoretically, and
> > II+ shared the same components and production lines for a time.  Only
> diff
> > was the ROMs.  Now Rev 0 is where it's at, especially a rare ventless
> > case.  Oh, and late SNs in the 7 range for some reason still get
> > $700-800.  I don't know why.
> >
> > The one thing I can tell you is, if an 'expert' tells you something about
> > original II production, there's a good chance they are wrong.  Some
> > authoritative sources claimed no Rev 02 boards went into public hands,
> for
> > example, but I have one in my SN 16000s machine.  Some would claim that
> > can't be original, but it is.. the date code on it is the same as the
> > keyboard and case, all right in the range of other 16000 series machines,
> > which on either side of mine have Rev 03.  Apple didn't use the same rev
> > consistently.. sometimes they just grabbed from the pile.  It's kind of a
> > dogs breakfast after Rev 0.
> >
> > My Rev 02 operates no differently, other than Integer BASIC, than my RFI
> > II+.  More and more I'm not finding IIs to be all that amazing or worth
> > fighting over.  A Rev 0, just owing to the few truly unique design
> > features, is the only one I might want now.
> >
> >
> >
> >
>
> Yeah.  We were on to IIes when I was in grade school and then Commodores
> and PCs after that.. original IIs and II+ were long gone.  I have four
> units and never have any issue but come to think of it I do tend to run
> them case top off.  I imagine other users might have run them with the
> monitor (another massive heat source) sitting right on top.
> I think the ventless cases also were made of a weaker plastic that melted
> and warped just from the heat of the innards.  The few examples I've seen
> are almost invariably somewhat concave.

Re: Fix for 4.3BSD-Quasijarus bootstrap on CMD SCSI controllers

[Holm Tiffe]

David Brownlee wrote:

> On 3 January 2017 at 20:11, David Brownlee  wrote:
> > On 3 January 2017 at 15:50, Noel Chiappa  wrote:
> >> > From: Josh Dersch
> >>
> >> > Thought I'd share this fix with you all just in case someone in the
> >> > future might make use of it.
> >>
> >> To help disseminate it, I uploaded the fix to the Computer History wiki:
> >>
> >>   http://gunkies.org/wiki/CDU-710/M_disk_controller
> >>
> >>
> >> > From: Lars Brinkhoff
> >>
> >> > There's no central repository for fixes like these?
> >>
> >> Well, the CH wiki would be a good place, but creating new accounts on it is
> >> proving to be difficult.
> >>
> >> I'm trying to get ahold of one of the two bureacrats, to make me an admin
> >> (I've been one on Wikipedia since the Devonian), so I can create accounts 
> >> for
> >> people, but so far no luck.
> >>
> >> Noel
> >
> > Would it make sense for someone to import it to github?
> >
> > If nothing else it should be be easy enough to start with 0, then
> > update to 0a 0b and then 0c. so we have what history is available.
> >
> > (checks github)
> >
> > Aha - I see that johnwfinigan has already put up a 0c, though it
> > doesn't seem to have the 0, 0a & 0b history
> > https://github.com/johnwfinigan/4.3BSD-quasijarus0c/commits/master
> >
> > Actually I might just do the 0..0c history into a github entry myself,
> > then anyone else can just {v,}fork and take it from there as desired :-p
> 
> No sooner said than done :)
> 
> In case it proves of interest to anyone. Happy for it to be forked
> (obviously!) or to have patches or pull requests punted back to me
> 
> https://github.com/abs0/4.3BSD-Quasijarus
> 
> David

Could please someone check this file:

http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.gz
(or this one:
http://www.tiffe.de/Robotron/PDP-VAX/VAX/4BSD/Distributions/4.3/qjsrc-se53pra0.tar.Z)
against the repo?

If I remember correctly it contains some patches from Michael Sokolov not
contained in 0c.
I've had some conversations with him in the past, had a 0c running on a
KA630 System with Emulex UC08 and a 8Gig Tandberg Tape drive.

Regards,

Holm
-- 
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